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Kafali SG, Bolster BD, Shih SF, Delgado TI, Deshpande V, Zhong X, Adamos TR, Ghahremani S, Calkins KL, Wu HH. Self-Gated Radial Free-Breathing Liver MR Elastography: Assessment of Technical Performance in Children at 3 T. J Magn Reson Imaging 2024. [PMID: 39036994 DOI: 10.1002/jmri.29541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 07/05/2024] [Accepted: 07/08/2024] [Indexed: 07/23/2024] Open
Abstract
BACKGROUND Conventional liver magnetic resonance elastography (MRE) requires breath-holding (BH) to avoid motion artifacts, which is challenging for children. While radial free-breathing (FB)-MRE is an alternative for quantifying liver stiffness (LS), previous methods had limitations of long scan times, acquiring two slices in 5 minutes, and not resolving motion during reconstruction. PURPOSE To reduce FB-MRE scan time to 4 minutes for four slices and to investigate the impact of self-gated (SG) motion compensation on FB-MRE LS quantification in terms of agreement, intrasession repeatability, and technical quality compared to conventional BH-MRE. STUDY TYPE Prospective. POPULATION Twenty-six children without fibrosis (median age: 12.9 years, 15 females). FIELD STRENGTH/SEQUENCE 3 T; Cartesian gradient-echo (GRE) BH-MRE, research application radial GRE FB-MRE. ASSESSMENT Participants were scanned twice to measure repeatability, without moving the table or changing the participants' position. LS was measured in areas of the liver with numerical confidence ≥90%. Technical quality was examined using measurable liver area (%). STATISTICAL TESTS Agreement of LS between BH-MRE and FB-MRE was evaluated using Bland-Altman analysis for SG acceptance rates of 40%, 60%, 80%, and 100%. LS repeatability was assessed using within-subject coefficient of variation (wCV). The differences in LS and measurable liver area were examined using Kruskal-Wallis and Wilcoxon signed-rank tests. P < 0.05 was considered significant. RESULTS FB-MRE with 60% SG achieved the closest agreement with BH-MRE (mean difference 0.00 kPa). The LS ranged from 1.70 to 1.83 kPa with no significant differences between BH-MRE and FB-MRE with varying SG rates (P = 0.52). All tested methods produced repeatable LS with wCV from 4.4% to 6.5%. The median measurable liver area was smaller for FB-MRE (32%-45%) than that for BH-MRE (91%-93%) (P < 0.05). DATA CONCLUSION FB-MRE with 60% SG can quantify LS with close agreement and comparable repeatability with respect to BH-MRE in children. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Sevgi Gokce Kafali
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA
| | - Bradley D Bolster
- US MR R&D Collaborations, Siemens Medical Solutions USA, Inc., Salt Lake City, Utah, USA
| | - Shu-Fu Shih
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA
| | - Timoteo I Delgado
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Physics and Biology in Medicine Interdepartmental Program, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Vibhas Deshpande
- US MR R&D Collaborations, Siemens Medical Solutions USA, Inc., Austin, Texas, USA
| | - Xiaodong Zhong
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA
- Physics and Biology in Medicine Interdepartmental Program, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Timothy R Adamos
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Shahnaz Ghahremani
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Kara L Calkins
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Holden H Wu
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, USA
- Physics and Biology in Medicine Interdepartmental Program, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
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Sango-Solanas P, Tse Ve Koon K, Van Reeth E, Nicolle S, Palierne JF, Caussy C, Beuf O. Ultrashort echo time magnetic resonance elastography for quantification of the mechanical properties of short T2 tissues via optimal control-based radiofrequency pulses. NMR IN BIOMEDICINE 2024:e5210. [PMID: 38993021 DOI: 10.1002/nbm.5210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 05/22/2024] [Accepted: 06/11/2024] [Indexed: 07/13/2024]
Abstract
The aim of the current study is to demonstrate the feasibility of radiofrequency (RF) pulses generated via an optimal control (OC) algorithm to perform magnetic resonance elastography (MRE) and quantify the mechanical properties of materials with very short transverse relaxation times (T2 < 5 ms) for the first time. OC theory applied to MRE provides RF pulses that bring isochromats from the equilibrium state to a fixed target state, which corresponds to the phase pattern of a conventional MRE acquisition. Such RF pulses applied with a constant gradient allow to simultaneously perform slice selection and motion encoding in the slice direction. Unlike conventional MRE, no additional motion-encoding gradients (MEGs) are needed, enabling shorter echo times. OC pulses were implemented both in turbo spin echo (OC rapid acquisition with refocused echoes [RARE]) and ultrashort echo time (OC UTE) sequences to compare their motion-encoding efficiency with the conventional MEG encoding (classical MEG MRE). MRE experiments were carried out on agar phantoms with very short T2 values and on an ex vivo bovine tendon. Magnitude images, wave field images, phase-to-noise ratio (PNR), and shear storage modulus maps were compared between OC RARE, OC UTE, and classical MEG MRE in samples with different T2 values. Shear storage modulus values of the agar phantoms were in agreement with values found in the literature, and that of the bovine tendon was corroborated with rheometry measurements. Only the OC sequences could encode motion in very short T2 samples, and only OC UTE sequences yielded magnitude images enabling proper visualization of short T2 samples and tissues. The OC UTE sequence produced the best PNRs, demonstrating its ability to perform anatomical and mechanical characterization. Its success warrants in vivo confirmation in further studies.
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Affiliation(s)
- Pilar Sango-Solanas
- Univ Lyon, INSA-Lyon, Inserm, UCBL1, CNRS, CREATIS, UMR 5220, U1294, Villeurbanne, France
| | - Kevin Tse Ve Koon
- Univ Lyon, INSA-Lyon, Inserm, UCBL1, CNRS, CREATIS, UMR 5220, U1294, Villeurbanne, France
| | - Eric Van Reeth
- Univ Lyon, INSA-Lyon, Inserm, UCBL1, CNRS, CREATIS, UMR 5220, U1294, Villeurbanne, France
- CPE Lyon, Département Sciences du Numérique, Lyon, France
| | - Stéphane Nicolle
- Univ Lyon, Univ Gustave Eiffel, Univ Claude Bernard Lyon 1, LBMC UMR_T 9406, Lyon, France
| | | | - Cyrielle Caussy
- Univ Lyon, CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France
- Hospices Civils de Lyon, Département Endocrinologie, Diabète et Nutrition, Hôpital Lyon Sud, Pierre-Bénite, France
| | - Olivier Beuf
- Univ Lyon, INSA-Lyon, Inserm, UCBL1, CNRS, CREATIS, UMR 5220, U1294, Villeurbanne, France
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Qiu C, Glaser KJ, Owusu N, Li J, Wu H, Venkatesh SK, Manduca A, Ehman RL, Yin M. Acquisition Efficiency and Technical Repeatability of Dual-Frequency 3D Vector MR Elastography of the Liver. J Magn Reson Imaging 2024. [PMID: 38935749 DOI: 10.1002/jmri.29493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 06/05/2024] [Accepted: 06/05/2024] [Indexed: 06/29/2024] Open
Abstract
BACKGROUND MR elastography (MRE) at 60 Hz is widely used for staging liver fibrosis. MRE with lower frequencies may provide inflammation biomarkers. PURPOSE To establish a practical simultaneous dual-frequency liver MRE protocol at both 30 Hz and 60 Hz during a single examination and validate the occurrence of second harmonic waves at 30 Hz. STUDY TYPE Retrospective. SUBJECTS One hundred six patients (48 females, age: 50.0 ± 13.4 years) were divided as follows: Cohort One (15 patients with chronic liver disease [CLD] and 25 healthy volunteers) with simultaneous dual-frequency MRE. Cohort Two (66 patients with CLD) with second harmonic MRE. FIELD STRENGTH/SEQUENCE 3-T, single- or dual-frequency MRE at 30 Hz and 60 Hz. ASSESSMENT Liver stiffness (LS) in both cohorts was evaluated with manually placed volumetric ROIs by two independent analyzers. Image quality was assessed by three independent readers on a 4-point scale (0-3: none/failed, fair, moderate, excellent) based on the depth of wave propagation with 1/3 incremental penetration. The success rate was derived from the percentage of nonzero quality scores. STATISTICAL TESTS Measurement agreement, bias, and repeatability of LS were assessed using intraclass correlation coefficients (ICCs), Bland-Altman plots, and repeatability coefficient (RC). Mann-Whitney U tests were used to evaluate the differences in image quality between different methods. A P-value <0.05 was considered statistically significant. RESULTS Success rate was 97.5% in Cohort One and 91% success rate for the second harmonic MRE in Cohort Two. The second harmonic and conventional MRE showed excellent agreement in LS (all ICCs >0.90). The quality scores for the second harmonic wave images were lower than those from the conventional MRE (Z = -4.523). DATA CONCLUSION Compared with conventional and second harmonic methods, simultaneous dual-frequency had better image quality, high success rate and the advantage of intrinsic co-registration, while the second harmonic method can be an alternative if custom waveform is not available. EVIDENCE LEVEL 3 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Caixin Qiu
- Department of Radiology, Tianjin First Central Hospital, Tianjin, China
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Kevin J Glaser
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Nana Owusu
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Jiahui Li
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Hao Wu
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Armando Manduca
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Richard L Ehman
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Meng Yin
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
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Le Y, Chen J, Rossman P, Bolster B, Kannengiesser S, Manduca A, Glaser K, Sui Y, Huston J, Yin Z, Ehman RL. Wavelet MRE: Imaging propagating broadband acoustic waves with wavelet-based motion-encoding gradients. Magn Reson Med 2024; 91:1923-1935. [PMID: 38098427 PMCID: PMC10950519 DOI: 10.1002/mrm.29972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 10/24/2023] [Accepted: 11/26/2023] [Indexed: 03/20/2024]
Abstract
PURPOSE To demonstrate a novel MR elastography (MRE) technique, termed here wavelet MRE. With this technique, broadband motion sensitivity is achievable. Moreover, the true tissue displacement can be reconstructed with a simple inverse transform. METHODS A wavelet MRE sequence was developed with motion-encoding gradients based on Haar wavelets. From the phase images' displacement was estimated using an inverse transform. Simulations were performed using a frequency sweep and a transient as ground-truth motions. A PVC phantom was scanned using wavelet MRE and standard MRE with both transient (one and 10 cycles of 90-Hz motion) and steady-state dual-frequency motion (30 and 60 Hz) for comparison. The technique was tested in a human brain, and motion trajectories were estimated for each voxel. RESULTS In simulation, the displacement information estimated from wavelet MRE closely matched the true motion. In the phantom test, the MRE phase data generated from the displacement information derived from wavelet MRE agreed well with standard MRE data. Testing of wavelet MRE to assess transient motion waveforms in the brain was successful, and the tissue motion observed was consistent with a previous study. CONCLUSION The uniform and broadband frequency response of wavelet MRE makes it a promising method for imaging transient, multifrequency motion, or motion with unknown frequency content. One potential application is measuring the response of brain tissue undergoing low-amplitude, transient vibrations as a model for the study of traumatic brain injury.
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Affiliation(s)
- Yuan Le
- Department of Radiology, Mayo Clinic, Rochester, MN
| | - Jun Chen
- Department of Radiology, Mayo Clinic, Rochester, MN
| | | | - Bradley Bolster
- MR Collaborations, Siemens Medical Solutions USA, Inc., Malvern, PA, USA
| | | | | | - Kevin Glaser
- Department of Radiology, Mayo Clinic, Rochester, MN
| | - Yi Sui
- Department of Radiology, Mayo Clinic, Rochester, MN
| | - John Huston
- Department of Radiology, Mayo Clinic, Rochester, MN
| | - Ziying Yin
- Department of Radiology, Mayo Clinic, Rochester, MN
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Ito D, Numano T, Habe T, Okuda S, Nozaki T, Jinzaki M. Fast abdominal magnetic resonance elastography with simultaneous encoding of three-dimensional displacements. Magn Reson Imaging 2024; 108:138-145. [PMID: 38360120 DOI: 10.1016/j.mri.2024.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 02/07/2024] [Accepted: 02/11/2024] [Indexed: 02/17/2024]
Abstract
Three-dimensional (3D) magnetic resonance elastography (MRE) is more accurate than two-dimensional (2D) MRE; however, it requires long-term acquisition. This study aimed to reduce the acquisition time of abdominal 3D MRE using a new sample interval modulation (short-SLIM) approach that can acquire all three motions faster while reducing the prolongation of echo time and flow compensation. To this end, two types of phantom studies and an in vivo test of the liver in three healthy volunteers were performed to compare the performances of conventional spin-echo echo-planar (SE-EPI) MRE, conventional SLIM and short-SLIM. One phantom study measured the mean amplitude and shear modulus within the overall region of a homogeneous phantom by changing the mechanical vibration power to assess the robustness to the lowered phase-to-noise ratio in short-SLIM. The other measured the mean shear modulus in the stiff and background materials of a phantom with an embedded stiffer rod to assess the performance of short-SLIM for complex wave patterns with wave interference. The Spearman's rank correlation coefficient was used to assess similarity of elastograms in the rod-embedded phantom and liver between methods. The results of the phantom study changing the vibration power indicated that there was little difference between conventional MRE and short-SLIM. Moreover, the elastogram pattern and the mean shear modulus in the rod-embedded phantom in conventional SLIM and short-SLIM did not change for conventional MRE; the liver test also showed a small difference between the acquisition techniques. This study demonstrates that short-SLIM can provide MRE results comparable to those of conventional MRE. Short-SLIM can reduce the total acquisition time by a factor of 2.25 compared to conventional 3D MRE time, leading to an improvement in the accuracy of shear modulus estimation by suppressing the patient movements.
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Affiliation(s)
- Daiki Ito
- Office of Radiation Technology, Keio University Hospital, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan; Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan.
| | - Tomokazu Numano
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan; Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-2-1, Namiki, Tsukuba-shi, Ibaraki 305-8564, Japan
| | - Tetsushi Habe
- Office of Radiation Technology, Keio University Hospital, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Shigeo Okuda
- Department of Diagnostic Radiology, National Tokyo Medical Center, 2-5-1, Higashigaoka, Meguro-ku, Tokyo 152-8902, Japan; Department of Radiology, Keio University School of Medicine, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Taiki Nozaki
- Department of Radiology, Keio University School of Medicine, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Masahiro Jinzaki
- Department of Radiology, Keio University School of Medicine, 35, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Wang R, Wang Y, Qiu S, Ma S, Yan F, Yang GZ, Li R, Feng Y. A Comparative Study of Three Systems for Liver Magnetic Resonance Elastography. J Magn Reson Imaging 2024. [PMID: 38449389 DOI: 10.1002/jmri.29335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/21/2024] [Accepted: 02/21/2024] [Indexed: 03/08/2024] Open
Abstract
BACKGROUND Different MR elastography (MRE) systems may produce different stiffness measurements, making direct comparison difficult in multi-center investigations. PURPOSE To assess the repeatability and reproducibility of liver stiffness measured by three typical MRE systems. STUDY TYPE Prospective. POPULATION/PHANTOMS Thirty volunteers without liver disease history (20 males, aged 21-28)/5 gel phantoms. FIELD STRENGTH/SEQUENCE 3.0 T United Imaging Healthcare (UIH), 1.5 T Siemens Healthcare, 3.0 T General Electric Healthcare (GE)/Echo planar imaging-based MRE sequence. ASSESSMENT Wave images of volunteers and phantoms were acquired by three MRE systems. Tissue stiffness was evaluated by two observers, while phantom stiffness was assessed automatically by code. The reproducibility across three MRE systems was quantified based on the mean stiffness of each volunteer and phantom. STATISTICAL TESTS Intraclass correlation coefficients (ICC), coefficients of variation (CV), and Bland-Altman analyses were used to assess the interobserver reproducibility, the interscan repeatability, and the intersystem reproducibility. Paired t-tests were performed to assess the interobserver and interscan variation. Friedman tests with Dunn's multiple comparison correction were performed to assess the intersystem variation. P values less than 0.05 indicated significant difference. RESULTS The reproducibility of stiffness measured by the two observers demonstrated consistency with ICC > 0.92, CV < 4.32%, Mean bias < 2.23%, and P > 0.06. The repeatability of measurements obtained using the electromagnetic system for the liver revealed ICC > 0.96, CV < 3.86%, Mean bias < 0.19%, P > 0.90. When considering the range of reproducibility across the three systems for liver evaluations, results ranged with ICCs from 0.70 to 0.87, CVs from 6.46% to 10.99%, and Mean biases between 1.89% and 6.30%. Phantom studies showed similar results. The values of measured stiffness differed across all three systems significantly. DATA CONCLUSION Liver stiffness values measured from different MRE systems can be different, but the measurements across the three MRE systems produced consistent results with excellent reproducibility. EVIDENCE LEVEL 1 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Runke Wang
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), Shanghai Jiao Tong University, Shanghai, China
| | - Yikun Wang
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Faculty of Medical Imaging Technology, College of Health Science and Technology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Suhao Qiu
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), Shanghai Jiao Tong University, Shanghai, China
| | - Shengyuan Ma
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), Shanghai Jiao Tong University, Shanghai, China
| | - Fuhua Yan
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Faculty of Medical Imaging Technology, College of Health Science and Technology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Guang-Zhong Yang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), Shanghai Jiao Tong University, Shanghai, China
| | - Ruokun Li
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Faculty of Medical Imaging Technology, College of Health Science and Technology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yuan Feng
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), Shanghai Jiao Tong University, Shanghai, China
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Wolf M, Darwish O, Neji R, Eder M, Sunder-Plassmann G, Heinz G, Robinson SD, Schmid AI, Moser EV, Sinkus R, Meyerspeer M. Magnetic resonance elastography resolving all gross anatomical segments of the kidney during controlled hydration. Front Physiol 2024; 15:1327407. [PMID: 38384795 PMCID: PMC10880033 DOI: 10.3389/fphys.2024.1327407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/24/2024] [Indexed: 02/23/2024] Open
Abstract
Introduction: Magnetic resonance elastography (MRE) is a non-invasive method to quantify biomechanical properties of human tissues. It has potential in diagnosis and monitoring of kidney disease, if established in clinical practice. The interplay of flow and volume changes in renal vessels, tubule, urinary collection system and interstitium is complex, but physiological ranges of in vivo viscoelastic properties during fasting and hydration have never been investigated in all gross anatomical segments simultaneously. Method: Ten healthy volunteers underwent two imaging sessions, one following a 12-hour fasting period and the second after a drinking challenge of >10 mL per kg body weight (60-75 min before the second examination). High-resolution renal MRE was performed using a novel driver with rotating eccentric mass placed at the posterior-lateral wall to couple waves (50 Hz) to the kidney. The biomechanical parameters, shear wave speed (cs in m/s), storage modulus (Gd in kPa), loss modulus (Gl in kPa), phase angle ( Υ = 2 π atan G l G d ) and attenuation (α in 1/mm) were derived. Accurate separation of gross anatomical segments was applied in post-processing (whole kidney, cortex, medulla, sinus, vessel). Results: High-quality shear waves coupled into all gross anatomical segments of the kidney (mean shear wave displacement: 163 ± 47 μm, mean contamination of second upper harmonics <23%, curl/divergence: 4.3 ± 0.8). Regardless of the hydration state, median Gd of the cortex and medulla (0.68 ± 0.11 kPa) was significantly higher than that of the sinus and vessels (0.48 ± 0.06 kPa), and consistently, significant differences were found in cs, Υ , and Gl (all p < 0.001). The viscoelastic parameters of cortex and medulla were not significantly different. After hydration sinus exhibited a small but significant reduction in median Gd by -0.02 ± 0.04 kPa (p = 0.01), and, consequently, the cortico-sinusoidal-difference in Gd increased by 0.04 ± 0.07 kPa (p = 0.05). Only upon hydration, the attenuation in vessels became lower (0.084 ± 0.013 1/mm) and differed significantly from the whole kidney (0.095 ± 0.007 1/mm, p = 0.01). Conclusion: High-resolution renal MRE with an innovative driver and well-defined 3D segmentation can resolve all renal segments, especially when including the sinus in the analysis. Even after a prolonged hydration period the approach is sensitive to small hydration-related changes in the sinus and in the cortico-sinusoidal-difference.
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Affiliation(s)
- Marcos Wolf
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Omar Darwish
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom
| | - Radhouene Neji
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Michael Eder
- Department of Medicine III, Division of Nephrology and Dialysis, General Hospital and Medical University of Vienna, Vienna, Austria
| | - Gere Sunder-Plassmann
- Department of Medicine III, Division of Nephrology and Dialysis, General Hospital and Medical University of Vienna, Vienna, Austria
| | - Gertraud Heinz
- Institut für Diagnostische und Interventionelle Radiologie, Universitätsklinikum St. Pölten, Sankt Pölten, Austria
| | - Simon Daniel Robinson
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
- Centre of Advanced Imaging, University of Queensland, Brisbane, QLD, Australia
| | - Albrecht Ingo Schmid
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Ewald V. Moser
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Ralph Sinkus
- Institut National de La Santé et de La Recherche Médicale, U1148, Laboratory for Vascular Translational Science, Paris, France
| | - Martin Meyerspeer
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
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Darwish OI, Gharib AM, Jeljeli S, Metwalli NS, Feeley J, Rotman Y, Brown RJ, Ouwerkerk R, Kleiner DE, Stäb D, Speier P, Sinkus R, Neji R. Single Breath-Hold 3-Dimensional Magnetic Resonance Elastography Depicts Liver Fibrosis and Inflammation in Obese Patients. Invest Radiol 2023; 58:413-419. [PMID: 36719974 PMCID: PMC10735168 DOI: 10.1097/rli.0000000000000952] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Three-dimensional (3D) magnetic resonance elastography (MRE) measures liver fibrosis and inflammation but requires several breath-holds that hamper clinical acceptance. The aim of this study was to evaluate the technical and clinical feasibility of a single breath-hold 3D MRE sequence as a means of measuring liver fibrosis and inflammation in obese patients. METHODS From November 2020 to December 2021, subjects were prospectively enrolled and divided into 2 groups. Group 1 included healthy volunteers (n = 10) who served as controls to compare the single breath-hold 3D MRE sequence with a multiple-breath-hold 3D MRE sequence. Group 2 included liver patients (n = 10) who served as participants to evaluate the clinical feasibility of the single breath-hold 3D MRE sequence in measuring liver fibrosis and inflammation. Controls and participants were scanned at 60 Hz mechanical excitation with the single breath-hold 3D MRE sequence to retrieve the magnitude of the complex-valued shear modulus (|G*| [kPa]), the shear wave speed (Cs [m/s]), and the loss modulus (G" [kPa]). The controls were also scanned with a multiple-breath-hold 3D MRE sequence for comparison, and the participants had histopathology (Ishak scores) for correlation with Cs and G". RESULTS For the 10 controls, 5 were female, and the mean age and body mass index were 33.1 ± 9.5 years and 23.0 ± 2.1 kg/m 2 , respectively. For the 10 participants, 8 were female, and the mean age and body mass index were 45.1 ± 16.5 years and 33.1 ± 4.0 kg/m 2 (obese range), respectively. All participants were suspected of having nonalcoholic fatty liver disease. Bland-Altman analysis of the comparison in controls shows there are nonsignificant differences in |G*|, Cs, and G" below 6.5%, suggesting good consensus between the 2 sequences. For the participants, Cs and G" correlated significantly with Ishak fibrosis and inflammation grades, respectively ( ρ = 0.95, P < 0.001, and ρ = 0.84, P = 0.002). CONCLUSION The single breath-hold 3D MRE sequence may be effective in measuring liver fibrosis and inflammation in obese patients.
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Affiliation(s)
- Omar Isam Darwish
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- INSERM U1148, LVTS, University Paris Diderot, Paris, France
- MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom
| | - Ahmed M. Gharib
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | - Sami Jeljeli
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Nader S. Metwalli
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | - Jenna Feeley
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | - Yaron Rotman
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | - Rebecca J. Brown
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | - Ronald Ouwerkerk
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | | | - Daniel Stäb
- MR Research Collaborations, Siemens Healthcare Limited, Melbourne, Australia
| | - Peter Speier
- MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany
| | - Ralph Sinkus
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- INSERM U1148, LVTS, University Paris Diderot, Paris, France
| | - Radhouene Neji
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom
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9
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Hazhirkarzar B, Wu Q, Tang H, Baghdadi A, Motaghi M, Habibabadi RR, Shaghaghi M, Ghadimi M, Borhani A, Mohseni A, Pan L, BolsterJr BD, Kamel IR. Comparison between Gradient-Echo and Spin-Echo EPI MR Elastography at 3 T in quantifying liver stiffness of patients with and without iron overload; a prospective study. Clin Imaging 2023; 100:42-47. [PMID: 37196504 DOI: 10.1016/j.clinimag.2023.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/28/2023] [Accepted: 05/08/2023] [Indexed: 05/19/2023]
Abstract
OBJECTIVES To compare the maximum axial area of the confidence mask and the calculated liver stiffness (LS) on gradient-echo (GRE) and spin-echo echo planar imaging (SE-EPI) MR elastography (MRE) in patients with and without iron deposition. METHODS 104 patients underwent MRE by GRE and SE-EPI sequences at 3 T. R2* values >88 Hz in the liver were categorized in the iron overload group. The maximum axial area and the corresponding LS values were measured by manually contouring the whole area on one slice with the largest confidence mask at both GRE and SE-EPI sequences. RESULTS In patients with iron overload, SE-EPI provided larger maximum axial confidence area in unfailed images (57.6 ± 41.7 cm2) compared to GRE (45.7 ± 29.1 cm2) (p-value = 0.007). In five patients with iron overload, imaging failed at GRE sequence, whereas at the SE-EPI sequence the maximum area of the confidence mask had a mean value of 33.5 ± 54.9 cm2. In livers without iron overload (R2*: 50.7 ± 13.1 Hz), the maximum area on the confidence mask was larger at SE-EPI (118.3 ± 41.2 cm2) than on GRE (105.1 ± 31.7 cm2) (P-value = 0.003). There was no significant difference in mean LS between SE-EPI (2.0 ± 0.3 kPa) and GRE (2.1 ± 0.5 kPa) in livers with iron overload (P value = 0.24). Similarly, in the group without iron overload, mean LS was 2.3 ± 0.7 kPa at SE-EPI and 2.4 ± 0.8 kPa at GRE sequences (P-value = 0.11). CONCLUSIONS SE-EPI MRE can successfully provide similar LS measurements as GRE MRE. Furthermore, it provides a larger measurable area on the confidence mask in both groups with and without iron overload.
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Affiliation(s)
- Bita Hazhirkarzar
- Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Qingxia Wu
- Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Hao Tang
- Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Azarakhsh Baghdadi
- Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Mina Motaghi
- Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Roya Rezvani Habibabadi
- Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Mohammadreza Shaghaghi
- Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Maryam Ghadimi
- Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Ali Borhani
- Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Alireza Mohseni
- Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Li Pan
- Siemens Healthineers, Baltimore, MD, USA
| | | | - Ihab R Kamel
- Russell H. Morgan Department of Radiology and Radiological Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
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10
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Li Y, Gao Q, Chen N, Zhang Y, Wang J, Li C, He X, Jiao Y, Zhang Z. Clinical studies of magnetic resonance elastography from 1995 to 2021: Scientometric and visualization analysis based on CiteSpace. Quant Imaging Med Surg 2022; 12:5080-5100. [PMID: 36330182 PMCID: PMC9622435 DOI: 10.21037/qims-22-207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 08/11/2022] [Indexed: 02/05/2023]
Abstract
BACKGROUND To assess the knowledge framework around magnetic resonance elastography (MRE) and to explore MRE research hotspots and emerging trends. METHODS The Science Citation Index Expanded of the Web of Science Core Collection was searched on 22 October 2021 for MRE-related studies published between 1995 and 2021. Excel 2016 and CiteSpace V (version 5.8.R3) were used to analyze the downloaded data. RESULTS In all, 1,236 articles published by 726 authors from 540 institutions in 40 countries were included in this study. The top 10 authors published 57.6% of all included articles. The 3 most productive countries were the USA (n=631), Germany (n=202), and France (n=134), and the 3 most productive institutions were the Mayo Clinic (n=240), Charité (n=131), and the University of Illinois (n=56). The USA and the Mayo Clinic had the highest betweenness centrality among countries and institutions, respectively, and played an important role in the field of MRE. In this study, the 24,347 distinct references were clustered into 48 categories via reasonable clustering using specific keywords, forming the knowledge framework. Among the 294 co-occurring keywords, "hepatic fibrosis", "stiffness", "skeletal muscle", "acoustic strain wave", "in vivo", and "non-invasive assessment" were research hotspots. "Diagnostic performance", "diagnostic accuracy", "hepatic steatosis", "chronic hepatitis B", "radiation force impulse", "children", and "echo" were frontier topics. CONCLUSIONS Scientometric and visualized analysis of MRE can provide information regarding the knowledge framework, research hotspots, frontier areas, and emerging trends in this field.
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Affiliation(s)
- Youwei Li
- Department of Radiology, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Qiang Gao
- Department of Gastroenterology and Hepatology, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Na Chen
- Department of Otorhinolaryngology, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Yuanfang Zhang
- Department of Radiology, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Juan Wang
- Department of Radiology, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Chang Li
- Department of Radiology, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Xuan He
- Department of Radiology, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Yang Jiao
- Department of Rehabilitation Psychology, Beijing Rehabilitation Hospital, Capital Medical University, Beijing, China
| | - Zongming Zhang
- Department of General Surgery, Beijing Electric Power Hospital, State Grid Corporation of China, Capital Medical University, Beijing, China
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11
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Yushchenko M, Sarracanie M, Salameh N. Fast acquisition of propagating waves in humans with low-field MRI: Toward accessible MR elastography. SCIENCE ADVANCES 2022; 8:eabo5739. [PMID: 36083901 PMCID: PMC9462689 DOI: 10.1126/sciadv.abo5739] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 07/22/2022] [Indexed: 05/29/2023]
Abstract
Most commonly used at clinical magnetic fields (1.5 to 3 T), magnetic resonance elastography (MRE) captures mechanical wave propagation to reconstruct the mechanical properties of soft tissue with MRI. However, in terms of noninvasively assessing disease progression in a broad range of organs (e.g., liver, breast, skeletal muscle, and brain), its accessibility is limited and its robustness is challenged when magnetic susceptibility differences are encountered. Low-field MRE offers an opportunity to overcome these issues, and yet it has never been demonstrated in vivo in humans with magnetic fields <1.5 T mainly because of the long acquisition times required to achieve a sufficient signal-to-noise ratio. Here, we describe a method to accelerate 3D motion-sensitized MR scans at 0.1 T using only 10% k-space sampling combined with a high-performance detector and an efficient encoding acquisition strategy. Its application is demonstrated in vivo in the human forearm for a single motion-encoding direction in less than 1 min.
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12
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Tardieu M, Salameh N, Souris L, Rousseau D, Jourdain L, Skeif H, Prévot F, de Rochefort L, Ducreux D, Louis B, Garteiser P, Sinkus R, Darrasse L, Poirier-Quinot M, Maître X. Magnetic resonance elastography with guided pressure waves. NMR IN BIOMEDICINE 2022; 35:e4701. [PMID: 35088465 DOI: 10.1002/nbm.4701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
Magnetic resonance elastography aims to non-invasively and remotely characterize the mechanical properties of living tissues. To quantitatively and regionally map the shear viscoelastic moduli in vivo, the technique must achieve proper mechanical excitation throughout the targeted tissues. Although it is straightforward, ante manibus, in close organs such as the liver or the breast, which practitioners clinically palpate already, it is somewhat fortunately highly challenging to trick the natural protective barriers of remote organs such as the brain. So far, mechanical waves have been induced in the latter by shaking the surrounding cranial bones. Here, the skull was circumvented by guiding pressure waves inside the subject's buccal cavity so mechanical waves could propagate from within through the brainstem up to the brain. Repeatable, reproducible and robust displacement fields were recorded in phantoms and in vivo by magnetic resonance elastography with guided pressure waves such that quantitative mechanical outcomes were extracted in the human brain.
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Affiliation(s)
- Marion Tardieu
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
- Montpellier Cancer Research Institute (IRCM), Inserm U1194, University of Montpellier, Montpellier, France
| | - Najat Salameh
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
- Center for Adaptable MRI Technology, Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Line Souris
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
| | | | - Laurène Jourdain
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
| | - Hanadi Skeif
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
| | - François Prévot
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
| | - Ludovic de Rochefort
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
- Aix-Marseille Université, CNRS, CRMBM, Marseille, France
- AP-HM, CHU Timone, Pôle d'Imagerie Médicale, CEMEREM, Marseille, France
| | - Denis Ducreux
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
| | - Bruno Louis
- Inserm-UPEC UMR955, CNRS EMR7000, Equipe Biomécanique Cellulaire et Respiratoire, Créteil, France
| | - Philippe Garteiser
- Laboratory of Imaging Biomarkers, Center for Research on Inflammation, UMR 1149, Inserm, Université de Paris, Paris, France
| | - Ralph Sinkus
- Imaging Sciences & Biomedical Engineering Division, King's College, London, United Kingdom
| | - Luc Darrasse
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
| | | | - Xavier Maître
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France
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13
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Triolo E, Khegai O, Ozkaya E, Rossi N, Alipour A, Fleysher L, Balchandani P, Kurt M. Design, Construction, and Implementation of a Magnetic Resonance Elastography Actuator for Research Purposes. Curr Protoc 2022; 2:e379. [PMID: 35286023 PMCID: PMC9517172 DOI: 10.1002/cpz1.379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Magnetic resonance elastography (MRE) is a technique for determining the mechanical response of soft materials using applied harmonic deformation of the material and a motion-sensitive magnetic resonance imaging sequence. This technique can elucidate significant information about the health and development of human tissue such as liver and brain, and has been used on phantom models (e.g., agar, silicone) to determine their suitability for use as a mechanical surrogate for human tissues in experimental models. The applied harmonic deformation used in MRE is generated by an actuator, transmitted in bursts of a specified duration, and synchronized with the magnetic resonance signal excitation. These actuators are most often a pneumatic design (common for human tissues or phantoms) or a piezoelectric design (common for small animal tissues or phantoms). Here, we describe how to design and assemble both a pneumatic and a piezoelectric MRE actuator for research purposes. For each of these actuator types, we discuss displacement requirements, end-effector options and challenges, electronics and electronic-driving requirements and considerations, and full MRE implementation. We also discuss how to choose the actuator type, size, and power based on the intended material and use. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Design, construction, and implementation of a convertible pneumatic MRE actuator for use with tissues and phantom models Basic Protocol 2: Design, construction, and implementation of a piezoelectric MRE actuator for localized excitation in phantom models.
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Affiliation(s)
- E.R. Triolo
- University of Washington, Dept. of Mechanical Engineering (3900 E Stevens Way NE Seattle, WA 98195)
| | - O. Khegai
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
| | - E. Ozkaya
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
| | - N. Rossi
- Stevens Institute of Technology, Dept. of Mechanical Engineering (1 Castle Point Terrace, Hoboken, NJ 07030)
| | - A. Alipour
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
| | - L. Fleysher
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
| | - P. Balchandani
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
| | - M. Kurt
- University of Washington, Dept. of Mechanical Engineering (3900 E Stevens Way NE Seattle, WA 98195)
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
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14
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Hannum AJ, McIlvain G, Sowinski D, McGarry MD, Johnson CL. Correlated noise in brain magnetic resonance elastography. Magn Reson Med 2022; 87:1313-1328. [PMID: 34687069 PMCID: PMC8776601 DOI: 10.1002/mrm.29050] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 09/13/2021] [Accepted: 09/28/2021] [Indexed: 12/22/2022]
Abstract
PURPOSE Magnetic resonance elastography (MRE) uses phase-contrast MRI to generate mechanical property maps of the in vivo brain through imaging of tissue deformation from induced mechanical vibration. The mechanical property estimation process in MRE can be susceptible to noise from physiological and mechanical sources encoded in the phase, which is expected to be highly correlated. This correlated noise has yet to be characterized in brain MRE, and its effects on mechanical property estimates computed using inversion algorithms are undetermined. METHODS To characterize the effects of signal noise in MRE, we conducted 3 experiments quantifying (1) physiomechanical sources of signal noise, (2) physiological noise because of cardiac-induced movement, and (3) impact of correlated noise on mechanical property estimates. We use a correlation length metric to estimate the extent that correlated signal persists in MRE images and demonstrate the effect of correlated noise on property estimates through simulations. RESULTS We found that both physiological noise and vibration noise were greater than image noise and were spatially correlated across all subjects. Added physiological and vibration noise to simulated data resulted in property maps with higher error than equivalent levels of Gaussian noise. CONCLUSION Our work provides the foundation to understand contributors to brain MRE data quality and provides recommendations for future work to correct for signal noise in MRE.
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Affiliation(s)
- Ariel J. Hannum
- Department of Biomedical Engineering, University of Delaware, Newark, DE
| | - Grace McIlvain
- Department of Biomedical Engineering, University of Delaware, Newark, DE
| | - Damian Sowinski
- Thayer School of Engineering, Dartmouth College, Hanover, NH
| | | | - Curtis L. Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE
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15
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Short echo time dual-frequency MR Elastography with Optimal Control RF pulses. Sci Rep 2022; 12:1406. [PMID: 35082303 PMCID: PMC8791955 DOI: 10.1038/s41598-022-05262-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 01/03/2022] [Indexed: 01/05/2023] Open
Abstract
Magnetic Resonance Elastography (MRE) quantifies the mechanical properties of tissues, typically applying motion encoding gradients (MEG). Multifrequency results allow better characterizations of tissues using data usually acquired through sequential monofrequency experiments. High frequencies are difficult to reach due to slew rate limitations and low frequencies induce long TEs, yielding magnitude images with low SNR. We propose a novel strategy to perform simultaneous multifrequency MRE in the absence of MEGs: using RF pulses designed via the Optimal Control (OC) theory. Such pulses control the spatial distribution of the MRI magnetization phase so that the resulting transverse magnetization reproduces the phase pattern of an MRE acquisition. The pulse is applied with a constant gradient during the multifrequency mechanical excitation to simultaneously achieve slice selection and motion encoding. The phase offset sampling strategy can be adapted according to the excitation frequencies to reduce the acquisition time. Phantom experiments were run to compare the classical monofrequency MRE to the OC based dual-frequency MRE method and showed excellent agreement between the reconstructed shear storage modulus G′. Our method could be applied to simultaneously acquire low and high frequency components, which are difficult to encode with the classical MEG MRE strategy.
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16
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Wang R, Chen Y, Li R, Qiu S, Zhang Z, Yan F, Feng Y. Fast magnetic resonance elastography with multiphase radial encoding and harmonic motion sparsity based reconstruction. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac4a42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/11/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Objective. To achieve fast magnetic resonance elastography (MRE) at a low frequency for better shear modulus estimation of the brain. Approach. We proposed a multiphase radial DENSE MRE (MRD-MRE) sequence and an improved GRASP algorithm utilizing the sparsity of the harmonic motion (SH-GRASP) for fast MRE at 20 Hz. For the MRD-MRE sequence, the initial position encoded by spatial modulation of magnetization (SPAMM) was decoded by an arbitrary number of readout blocks without increasing the number of phase offsets. Based on the harmonic motion, a modified total variation and temporal Fourier transform were introduced to utilize the sparsity in the temporal domain. Both phantom and brain experiments were carried out and compared with that from multiphase Cartesian DENSE-MRE (MCD-MRE), and conventional gradient echo sequence (GRE-MRE). Reconstruction performance was also compared with GRASP and compressed sensing. Main results. Results showed the scanning time of a fully sampled image with four phase offsets for MRD-MRE was only 1/5 of that from GRE-MRE. The wave patterns and estimated stiffness maps were similar to those from MCD-MRE and GRE-MRE. With SH-GRASP, the total scan time could be shortened by additional 4 folds, achieving a total acceleration factor of 20. Better metric values were also obtained using SH-GRASP for reconstruction compared with other algorithms. Significance. The MRD-MRE sequence and SH-GRASP algorithm can be used either in combination or independently to accelerate MRE, showing the potentials for imaging the brain as well as other organs.
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17
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Shan X, Yang J, Xu P, Hu L, Ge H. Deep neural networks for magnetic resonance elastography acceleration in thermal ablation monitoring. Med Phys 2022; 49:1803-1813. [PMID: 35061250 DOI: 10.1002/mp.15471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 12/03/2021] [Accepted: 12/31/2021] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To develop a deep neural network for accelerating magnetic resonance elastography (MRE) acquisition, to validate the ability to generate reliable MRE results with the down-sampled k-space data, and to demonstrate the feasibility of the proposed method in monitoring the stiffness changes during thermal ablation in a phantom study. MATERIALS AND METHODS MRE scans were performed with 60 Hz excitation on porcine ex-vivo liver gel phantoms in a 0.36T MRI scanner to generate the training dataset. The acquisition protocol was based on a spin-echo MRE pulse sequence with tailored motion-sensitive gradients to reduce echo time (TE). A U-Net based deep neural network was developed and trained to interpolate the missing data from down-sampled k-space. We calculated the errors of 80 sets magnitude/phase images reconstructed from the zero-filled, compressive sensing (CS) and deep learning (DL) method for comparison. The peak signal-to-noise rate (PSNR) and structural similarity (SSIM) of the magnitude/phase images were also calculated for comparison. The stiffness changes were recorded before, during, and after ablation. The mean stiffness values over the region of interest (ROI) were compared between the elastograms reconstructed from the fully-sampled k-space and interpolated k-space after thermal ablation. RESULTS The mean absolute error (MAE), PSNR, and SSIM of the proposed deep learning approach were significantly better than the results from the zero-filled method (p<0.0001) and CS (p<0.0001). The stiffness changes before and after thermal ablation assessed by the proposed approach (before: 7.7±1.1 kPa, after: 11.9±4.0 kPa, 4.2-kPa increase) gave close agreement with the values calculated from the fully-sampled data (before: 8.0±1.0 kPa, after: 12.6±4.2 kPa, 4.6-kPa increase). In contrast, the stiffness changes computed from the zero-filled method (before: 4.9±1.4 kPa, after: 5.6±2.8 kPa, 0.7-kPa increase) were substantially underestimated. CONCLUSION This study demonstrated the capability of the proposed deep learning method for rapid MRE acquisition and provided a promising solution for monitoring the MRI-guided thermal ablation. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Xiang Shan
- School of Medical Imaging, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Jinying Yang
- Laboratory Center for Information Science, University of Science and Technology of China, Hefei, Anhui, China
| | - Peng Xu
- Department of Radiology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Liangliang Hu
- School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei, Anhui, China
| | - Haitao Ge
- School of Medical Imaging, Xuzhou Medical University, Xuzhou, Jiangsu, China
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18
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Kafali SG, Armstrong T, Shih SF, Kim GJ, Holtrop JL, Venick RS, Ghahremani S, Bolster BD, Hillenbrand CM, Calkins KL, Wu HH. Free-breathing radial magnetic resonance elastography of the liver in children at 3 T: a pilot study. Pediatr Radiol 2022; 52:1314-1325. [PMID: 35366073 PMCID: PMC9192470 DOI: 10.1007/s00247-022-05297-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 12/02/2021] [Accepted: 01/20/2022] [Indexed: 12/17/2022]
Abstract
BACKGROUND Magnetic resonance (MR) elastography of the liver measures hepatic stiffness, which correlates with the histopathological staging of liver fibrosis. Conventional Cartesian gradient-echo (GRE) MR elastography requires breath-holding, which is challenging for children. Non-Cartesian radial free-breathing MR elastography is a potential solution to this problem. OBJECTIVE To investigate radial free-breathing MR elastography for measuring hepatic stiffness in children. MATERIALS AND METHODS In this prospective pilot study, 14 healthy children and 9 children with liver disease were scanned at 3 T using 2-D Cartesian GRE breath-hold MR elastography (22 s/slice) and 2-D radial GRE free-breathing MR elastography (163 s/slice). Each sequence was acquired twice. Agreement in the stiffness measurements was evaluated using Lin's concordance correlation coefficient (CCC) and within-subject mean difference. The repeatability was assessed using the within-subject coefficient of variation and intraclass correlation coefficient (ICC). RESULTS Fourteen healthy children and seven children with liver disease completed the study. Median (±interquartile range) normalized measurable liver areas were 62.6% (±26.4%) and 44.1% (±39.6%) for scan 1, and 60.3% (±21.8%) and 43.9% (±44.2%) for scan 2, for Cartesian and radial techniques, respectively. Hepatic stiffness from the Cartesian and radial techniques had close agreement with CCC of 0.89 and 0.94, and mean difference of 0.03 kPa and -0.01 kPa, for scans 1 and 2. Cartesian and radial techniques achieved similar repeatability with within-subject coefficient of variation=1.9% and 3.4%, and ICC=0.93 and 0.92, respectively. CONCLUSION In this pilot study, radial free-breathing MR elastography was repeatable and in agreement with Cartesian breath-hold MR elastography in children.
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Affiliation(s)
- Sevgi Gokce Kafali
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 300 UCLA Medical Plaza, Suite B119, Los Angeles, CA 90095 USA ,Department of Bioengineering, University of California Los Angeles, Los Angeles, CA USA
| | - Tess Armstrong
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 300 UCLA Medical Plaza, Suite B119, Los Angeles, CA 90095 USA
| | - Shu-Fu Shih
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 300 UCLA Medical Plaza, Suite B119, Los Angeles, CA 90095 USA ,Department of Bioengineering, University of California Los Angeles, Los Angeles, CA USA
| | - Grace J. Kim
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 300 UCLA Medical Plaza, Suite B119, Los Angeles, CA 90095 USA
| | - Joseph L. Holtrop
- Department of Diagnostic Imaging, St. Jude Children’s Research Hospital, Memphis, TN USA
| | - Robert S. Venick
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA USA
| | - Shahnaz Ghahremani
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 300 UCLA Medical Plaza, Suite B119, Los Angeles, CA 90095 USA
| | | | - Claudia M. Hillenbrand
- Department of Diagnostic Imaging, St. Jude Children’s Research Hospital, Memphis, TN USA ,Research Imaging NSW, University of New South Wales, Sydney, Australia
| | - Kara L. Calkins
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA USA
| | - Holden H. Wu
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 300 UCLA Medical Plaza, Suite B119, Los Angeles, CA 90095 USA ,Department of Bioengineering, University of California Los Angeles, Los Angeles, CA USA
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A novel technique for automating stiffness measurement and emphasizing the main wave: Coherent-wave auto-selection (CHASE). Magn Reson Imaging 2021; 85:133-140. [PMID: 34687851 DOI: 10.1016/j.mri.2021.10.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/17/2021] [Accepted: 10/17/2021] [Indexed: 11/20/2022]
Abstract
This study aims to develop and assess a new automated processing technique in MR elastography (MRE), namely coherent-wave auto-selection (CHASE). CHASE enables automatic selection of the region of interest (ROI) for stiffness measurement by extraction of the coherent wave region (CHASE ROI), and it improves the reconstruction of stiffness by a directional filter oriented along the main wave in each pixel (CHASE filtering). In this study, MRE of a phantom and of the liver of four healthy volunteers was performed. To investigate the potential of CHASE, this study assessed the CHASE according to three indices through the phantom study: 1) agreement on the ROI settings between CHASE and expert observers, 2) noise dependency, and 3) effect of the CHASE on stiffness variability within the CHASE ROI. The agreements on the ROI settings were analyzed by Cohen's kappa coefficient (κ). The noise dependency was analyzed by the mean absolute percentage errors (MAPEs) within the ROI between low (20%-80% amplitudes) and high vibration amplitudes (100% amplitude). The stiffness variability was assessed by standard deviation (SD) within the ROI. In the volunteer study, agreements on the ROI settings (or stiffness value) and stiffness variability within the CHASE ROI were assessed using κ-value (or intraclass correlation coefficient: ICC) and coefficient of variation, respectively. The results showed close agreement on the ROI settings and stiffness (κ-value: greater than 0.61 in both the phantom and volunteer studies, ICC: 0.97 in the volunteer study). The MAPEs within the CHASE ROI were much smaller than those in the whole region of the phantom (CHASE ROI vs. the whole region at 20% amplitude: 10.3% vs. 50.8%). Moreover, in both the phantom and volunteer studies, the stiffness variation within the CHASE ROI was smaller in the elastogram processed with CHASE filtering than in the unprocessed one. Our results demonstrated that the CHASE has high robustness against noise and the potential to provide ROI settings for stiffness measurement comparable to expert observers, as well as improve the reconstruction of stiffness.
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20
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Peng X, Sui Y, Trzasko JD, Glaser KJ, Huston J, Ehman RL, Pipe JG. Fast 3D MR elastography of the whole brain using spiral staircase: Data acquisition, image reconstruction, and joint deblurring. Magn Reson Med 2021; 86:2011-2024. [PMID: 34096097 PMCID: PMC8498799 DOI: 10.1002/mrm.28855] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 04/06/2021] [Accepted: 05/04/2021] [Indexed: 02/06/2023]
Abstract
PURPOSE To address the need for a method to acquire 3D data for MR elastography (MRE) of the whole brain with substantially improved spatial resolution, high SNR, and reduced acquisition time compared with conventional methods. METHODS We combined a novel 3D spiral staircase data-acquisition method with a spoiled gradient-echo pulse sequence and MRE motion-encoding gradients (MEGs). The spiral-out acquisition permitted use of longer-duration motion-encoding gradients (ie, over two full oscillatory cycles) to enhance displacement SNR, while still maintaining a reasonably short TE for good phase-SNR. Through-plane parallel imaging with low noise penalties was implemented to accelerate acquisition along the slice direction. Shared anatomical information was exploited in the deblurring procedure to further boost SNR for stiffness inversion. RESULTS In vivo and phantom experiments demonstrated the feasibility of the proposed method in producing brain MRE results comparable to the spin-echo-based approaches, both qualitatively and quantitatively. High-resolution (2-mm isotropic) brain MRE data were acquired in 5 minutes using our method with good SNR. Joint deblurring with shared anatomical information produced SNR-enhanced images, leading to upward stiffness estimation. CONCLUSION A novel 3D gradient-echo-based approach has been designed and implemented, and shown to have promising potential for fast and high-resolution in vivo MRE of the whole brain.
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Affiliation(s)
- Xi Peng
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Yi Sui
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Kevin J Glaser
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - John Huston
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Richard L Ehman
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - James G Pipe
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
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21
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Bayly PV, Alshareef A, Knutsen AK, Upadhyay K, Okamoto RJ, Carass A, Butman JA, Pham DL, Prince JL, Ramesh KT, Johnson CL. MR Imaging of Human Brain Mechanics In Vivo: New Measurements to Facilitate the Development of Computational Models of Brain Injury. Ann Biomed Eng 2021; 49:2677-2692. [PMID: 34212235 PMCID: PMC8516723 DOI: 10.1007/s10439-021-02820-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 06/22/2021] [Indexed: 01/04/2023]
Abstract
Computational models of the brain and its biomechanical response to skull accelerations are important tools for understanding and predicting traumatic brain injuries (TBIs). However, most models have been developed using experimental data collected on animal models and cadaveric specimens, both of which differ from the living human brain. Here we describe efforts to noninvasively measure the biomechanical response of the human brain with MRI-at non-injurious strain levels-and generate data that can be used to develop, calibrate, and evaluate computational brain biomechanics models. Specifically, this paper reports on a project supported by the National Institute of Neurological Disorders and Stroke to comprehensively image brain anatomy and geometry, mechanical properties, and brain deformations that arise from impulsive and harmonic skull loadings. The outcome of this work will be a publicly available dataset ( http://www.nitrc.org/projects/bbir ) that includes measurements on both males and females across an age range from adolescence to older adulthood. This article describes the rationale and approach for this study, the data available, and how these data may be used to develop new computational models and augment existing approaches; it will serve as a reference to researchers interested in using these data.
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Affiliation(s)
- Philip V Bayly
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, USA.
| | - Ahmed Alshareef
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Andrew K Knutsen
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Kshitiz Upadhyay
- Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Ruth J Okamoto
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, USA
| | - Aaron Carass
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - John A Butman
- Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Dzung L Pham
- Center for Neuroscience and Regenerative Medicine, The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Jerry L Prince
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - K T Ramesh
- Hopkins Extreme Materials Institute, Johns Hopkins University, Baltimore, MD, USA
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Curtis L Johnson
- Department of Biomedical Engineering, University of Delaware, Newark, DE, USA.
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22
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Plaikner M, Kremser C, Zoller H, Kannengiesser S, Henninger B. MR elastography in patients with suspected diffuse liver disease at 1.5T: Intraindividual comparison of gradient-recalled echo versus spin-echo echo-planar imaging sequences and investigation of potential confounding factors. Eur J Radiol 2021; 142:109898. [PMID: 34388628 DOI: 10.1016/j.ejrad.2021.109898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 12/16/2022]
Abstract
PURPOSE To compare liver stiffness (LS) in patients with suspected diffuse liver disease between gradient-recalled-echo magnetic resonance elastography (GRE-MRE) and different spin-echo echo-planar imaging (SE-EPI-MRE) sequences and to investigate confounding factors including fat, iron, age, and sex. METHOD LS was measured at 1.5T using GRE-MRE, SE-EPI-MRE and short-TE-SE-EPI-MRE (hiSE-EPI-MRE) sequences and compared using Bland-Altman-plots together with concordance correlation coefficients (CCC). Success gradings were evaluated considering possible confounding factors. RESULTS 305 patients (225 male, 80 females, mean age 51.12 years) were included. 109/305 showed hepatic iron overload, 183 hepatic steatosis. The mean difference (bias) in stiffness values between GRE-MRE and SE-EPI-MRE/hiSE-EPI-MRE was 0.15/0.2 kPa (LOA: -0.72,0.41 kPa/-0.94,0.55 kPa), between SE-EPI-MRE and hiSE-EPI-MRE 0.04 kPa (LOA: -0.62,0.53 kPa). The CCC for agreement between stiffness values for GRE-MRE and SE-EPI-MRE was 0.94 (0.92-0.95), 0.89 (0.86-0.91) for hiSE-EPI-MRE and GRE-MRE and 0.94 (0.92-0.95) for SE-EPI-MRE and hiSE-EPI-MRE. Using GRE-MRE, 72/305 showed unusable results whereby all these patients had high iron levels (mean R2*=209.7 1/s). For SE-EPI-MRE and hiSE-EPI-MRE only 10/305 and 8/305 were inconclusive respectively, corresponding to a significantly higher iron load (mean R2*= 549.2 1/s for SE-EPI-MRE and 570.7 1/s for hiSE-EPI-MRE). Concerning fat, age or sex no significant influence on success was observed for all sequences. CONCLUSIONS Good agreement of LS values was observed between GRE-MRE and SE-EPI-MRE sequences. The number of successful exams, however, was considerably lower for GRE-MRE, mainly due to iron content. Study reference number: AN5093.
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Affiliation(s)
- Michaela Plaikner
- Medical University of Innsbruck, Department of Radiology, Innsbruck, Austria
| | - Christian Kremser
- Medical University of Innsbruck, Department of Radiology, Innsbruck, Austria.
| | - Heinz Zoller
- Medical University of Innsbruck, Department of Internal Medicine, Innsbruck, Austria
| | | | - Benjamin Henninger
- Medical University of Innsbruck, Department of Radiology, Innsbruck, Austria
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23
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Herthum H, Shahryari M, Tzschätzsch H, Schrank F, Warmuth C, Görner S, Hetzer S, Neubauer H, Pfeuffer J, Braun J, Sack I. Real-Time Multifrequency MR Elastography of the Human Brain Reveals Rapid Changes in Viscoelasticity in Response to the Valsalva Maneuver. Front Bioeng Biotechnol 2021; 9:666456. [PMID: 34026743 PMCID: PMC8131519 DOI: 10.3389/fbioe.2021.666456] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/07/2021] [Indexed: 12/31/2022] Open
Abstract
Modulation of cerebral blood flow and vascular compliance plays an important role in the regulation of intracranial pressure (ICP) and also influences the viscoelastic properties of brain tissue. Therefore, magnetic resonance elastography (MRE), the gold standard for measuring in vivo viscoelasticity of brain tissue, is potentially sensitive to cerebral autoregulation. In this study, we developed a multifrequency MMRE technique that provides serial maps of viscoelasticity at a frame rate of nearly 6 Hz without gating, i.e., in quasi-real time (rt-MMRE). This novel method was used to monitor rapid changes in the viscoelastic properties of the brains of 17 volunteers performing the Valsalva maneuver (VM). rt-MMRE continuously sampled externally induced vibrations comprising three frequencies of 30.03, 30.91, and 31.8 Hz were over 90 s using a steady-state, spiral-readout gradient-echo sequence. Data were processed by multifrequency dual elasto-visco (MDEV) inversion to generate maps of magnitude shear modulus | G∗| (stiffness) and loss angle φ at a frame rate of 5.4 Hz. As controls, the volunteers were examined to study the effects of breath-hold following deep inspiration and breath-hold following expiration. We observed that | G∗| increased while φ decreased due to VM and, less markedly, due to breath-hold in inspiration. Group mean VM values showed an early overshoot of | G∗| 2.4 ± 1.2 s after the onset of the maneuver with peak values of 6.7 ± 4.1% above baseline, followed by a continuous increase in stiffness during VM. A second overshoot of | G∗| occurred 5.5 ± 2.0 s after the end of VM with peak values of 7.4 ± 2.8% above baseline, followed by 25-s sustained recovery until the end of image acquisition. φ was constantly reduced by approximately 2% during the entire VM without noticeable peak values. This is the first report of viscoelasticity changes in brain tissue induced by physiological maneuvers known to alter ICP and detected by clinically applicable rt-MMRE. Our results show that apnea and VM slightly alter brain properties toward a more rigid-solid behavior. Overshooting stiffening reactions seconds after onset and end of VM reveal rapid autoregulatory processes of brain tissue viscoelasticity.
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Affiliation(s)
- Helge Herthum
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Mehrgan Shahryari
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Heiko Tzschätzsch
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Felix Schrank
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Carsten Warmuth
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Steffen Görner
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Stefan Hetzer
- Berlin Center for Advanced Neuroimaging (BCAN), Berlin, Germany
| | - Hennes Neubauer
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Josef Pfeuffer
- Application Development, Siemens Healthcare GmbH, Erlangen, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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Arani A, Manduca A, Ehman RL, Huston Iii J. Harnessing brain waves: a review of brain magnetic resonance elastography for clinicians and scientists entering the field. Br J Radiol 2021; 94:20200265. [PMID: 33605783 PMCID: PMC8011257 DOI: 10.1259/bjr.20200265] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Brain magnetic resonance elastography (MRE) is an imaging technique capable of accurately and non-invasively measuring the mechanical properties of the living human brain. Recent studies have shown that MRE has potential to provide clinically useful information in patients with intracranial tumors, demyelinating disease, neurodegenerative disease, elevated intracranial pressure, and altered functional states. The objectives of this review are: (1) to give a general overview of the types of measurements that have been obtained with brain MRE in patient populations, (2) to survey the tools currently being used to make these measurements possible, and (3) to highlight brain MRE-based quantitative biomarkers that have the highest potential of being adopted into clinical use within the next 5 to 10 years. The specifics of MRE methodology strategies are described, from wave generation to material parameter estimations. The potential clinical role of MRE for characterizing and planning surgical resection of intracranial tumors and assessing diffuse changes in brain stiffness resulting from diffuse neurological diseases and altered intracranial pressure are described. In addition, the emerging technique of functional MRE, the role of artificial intelligence in MRE, and promising applications of MRE in general neuroscience research are presented.
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Affiliation(s)
- Arvin Arani
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Armando Manduca
- Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
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Sango Solanas P, Tse Ve Koon K, Ratiney H, Millioz F, Caussy C, Beuf O. Harmonic wideband simultaneous dual-frequency MR Elastography. NMR IN BIOMEDICINE 2021; 34:e4442. [PMID: 33179393 DOI: 10.1002/nbm.4442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 10/21/2020] [Accepted: 10/21/2020] [Indexed: 06/11/2023]
Abstract
Magnetic resonance elastography (MRE) is used to non-invasively quantify viscoelastic properties of tissues based on the measurement of propagation characteristics of shear waves. Because some of these viscoelastic parameters show a frequency dependence, multifrequency analysis allows us to measure the wave propagation dispersion, leading to a better characterization of tissue properties. Conventionally, motion encoding gradients (MEGs) oscillating at the same frequency as the mechanical excitation encode motion. Hence, multifrequency data is usually obtained by sequentially repeating monochromatic wave excitations experiments at different frequencies. The result is that the total acquisition time is multiplied by a factor corresponding to the number of repetitions of monofrequency experiments, which is a major limitation of multifrequency MRE. In order to make it more accessible, a novel single-shot harmonic wideband dual-frequency MRE method is proposed. Two superposed shear waves of different frequencies are simultaneously generated and propagate in a sample. Trapezoidal oscillating MEGs are used to encode mechanical vibrations having frequencies that are an odd multiple of the MEG frequency. The number of phase offsets is optimized to reduce the acquisition time. For this purpose, a sampling method not respecting the Shannon theorem is used to produce a controlled temporal aliasing that allows us to encode both frequencies without any additional examination time. Phantom experiments were run to compare conventional monofrequency MRE with the single-shot dual-frequency MRE method and showed excellent agreement between the reconstructed shear storage moduli G'. In addition, dual-frequency MRE yielded an increased signal-to-noise ratio compared with conventional monofrequency MRE acquisitions when encoding the high frequency component. The novel proposed multifrequency MRE method could be applied to simultaneously acquire more than two frequency components, reducing examination time. Further studies are needed to confirm its applicability in preclinical and clinical models.
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Affiliation(s)
- Pilar Sango Solanas
- Univ Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France
| | - Kevin Tse Ve Koon
- Univ Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France
| | - Helene Ratiney
- Univ Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France
| | - Fabien Millioz
- Univ Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France
| | - Cyrielle Caussy
- Univ Lyon, CarMen Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France
- Hospices Civils de Lyon, Département Endocrinologie, Diabète et Nutrition, Hôpital Lyon Sud, Pierre-Bénite, France
| | - Olivier Beuf
- Univ Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France
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26
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Troelstra MA, Runge JH, Burnhope E, Polcaro A, Guenthner C, Schneider T, Razavi R, Ismail TF, Martorell J, Sinkus R. Shear wave cardiovascular MR elastography using intrinsic cardiac motion for transducer-free non-invasive evaluation of myocardial shear wave velocity. Sci Rep 2021; 11:1403. [PMID: 33446701 PMCID: PMC7809276 DOI: 10.1038/s41598-020-79231-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 11/30/2020] [Indexed: 01/29/2023] Open
Abstract
Changes in myocardial stiffness may represent a valuable biomarker for early tissue injury or adverse remodeling. In this study, we developed and validated a novel transducer-free magnetic resonance elastography (MRE) approach for quantifying myocardial biomechanics using aortic valve closure-induced shear waves. Using motion-sensitized two-dimensional pencil beams, septal shear waves were imaged at high temporal resolution. Shear wave speed was measured using time-of-flight of waves travelling between two pencil beams and corrected for geometrical biases. After validation in phantoms, results from twelve healthy volunteers and five cardiac patients (two left ventricular hypertrophy, two myocardial infarcts, and one without confirmed pathology) were obtained. Torsional shear wave speed in the phantom was 3.0 ± 0.1 m/s, corresponding with reference speeds of 2.8 ± 0.1 m/s. Geometrically-biased flexural shear wave speed was 1.9 ± 0.1 m/s, corresponding with simulation values of 2.0 m/s. Corrected septal shear wave speeds were significantly higher in patients than healthy volunteers [14.1 (11.0-15.8) m/s versus 3.6 (2.7-4.3) m/s, p = 0.001]. The interobserver 95%-limits-of-agreement in healthy volunteers were ± 1.3 m/s and interstudy 95%-limits-of-agreement - 0.7 to 1.2 m/s. In conclusion, myocardial shear wave speed can be measured using aortic valve closure-induced shear waves, with cardiac patients showing significantly higher shear wave speeds than healthy volunteers. This non-invasive measure may provide valuable insights into the pathophysiology of heart failure.
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Affiliation(s)
- Marian Amber Troelstra
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Jurgen Henk Runge
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Emma Burnhope
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
- Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Alessandro Polcaro
- Department of Chemical Engineering and Material Sciences, IQS School of Engineering, Universitat Ramon Llull, Via Augusta 390, 08017, Barcelona, Spain
| | - Christian Guenthner
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
- Philips Research, Hamburg, Germany
| | - Torben Schneider
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
- Philips, Guildford, UK
| | - Reza Razavi
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Tevfik F Ismail
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
- Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Jordi Martorell
- Department of Chemical Engineering and Material Sciences, IQS School of Engineering, Universitat Ramon Llull, Via Augusta 390, 08017, Barcelona, Spain.
| | - Ralph Sinkus
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
- Inserm U1148, LVTS, University Paris Diderot, University Paris 13, Paris, France
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Dong H, Jin N, Kannengiesser S, Raterman B, White RD, Kolipaka A. Magnetic resonance elastography for estimating in vivo stiffness of the abdominal aorta using cardiac-gated spin-echo echo-planar imaging: a feasibility study. NMR IN BIOMEDICINE 2021; 34:e4420. [PMID: 33021342 DOI: 10.1002/nbm.4420] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 09/02/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
INTRODUCTION Magnetic resonance elastography (MRE)-derived aortic stiffness is a potential biomarker for multiple cardiovascular diseases. Currently, gradient-recalled echo (GRE) MRE is a widely accepted technique to estimate aortic stiffness. However, multi-slice GRE MRE requires multiple breath-holds (BHs), which can be challenging for patients who cannot consistently hold their breath. The aim of this study was to investigate the feasibility of a multi-slice spin-echo echo-planar imaging (SE-EPI) MRE sequence for quantifying in vivo aortic stiffness using a free-breathing (FB) protocol and a single-BH protocol. METHOD On Scanner 1, 25 healthy subjects participated in the validation of FB SE-EPI against FB GRE. On Scanner 2, another 15 healthy subjects were recruited to compare FB SE-EPI with single-BH SE-EPI. Among all volunteers, five participants were studied on both scanners to investigate the inter-scanner reproducibility of FB SE-EPI aortic MRE. Bland-Altman analysis, Lin's concordance correlation coefficient (LCCC) and coefficient of variation (COV) were evaluated. The phase-difference signal-to-noise ratios (PD SNR) were compared. RESULTS Aortic MRE using FB SE-EPI and FB GRE yielded similar stiffnesses (paired t-test, P = 0.19), with LCCC = 0.97. The FB SE-EPI measurements were reproducible (intra-scanner LCCC = 0.96) and highly repeatable (LCCC = 0.99). The FB SE-EPI MRE was also reproducible across different scanners (inter-scanner LCCC = 0.96). Single-BH SE-EPI scans yielded similar stiffness to FB SE-EPI scans (LCCC = 0.99) and demonstrated a low COV of 2.67% across five repeated measurements. CONCLUSION Multi-slice SE-EPI aortic MRE using an FB protocol or a single-BH protocol is reproducible and repeatable with advantage over multi-slice FB GRE in reducing acquisition time. Additionally, FB SE-EPI MRE provides a potential alternative to BH scans for patients who have challenges in holding their breath.
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Affiliation(s)
- Huiming Dong
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Ning Jin
- Siemens Medical Solution, Columbus, Ohio, USA
| | | | - Brian Raterman
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Richard D White
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA
- Department of Internal Medicine-Division of Cardiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Arunark Kolipaka
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA
- Department of Internal Medicine-Division of Cardiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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Ariyurek C, Tasdelen B, Ider YZ, Atalar E. SNR Weighting for Shear Wave Speed Reconstruction in Tomoelastography. NMR IN BIOMEDICINE 2021; 34:e4413. [PMID: 32956538 DOI: 10.1002/nbm.4413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 08/31/2020] [Accepted: 09/06/2020] [Indexed: 06/11/2023]
Abstract
In tomoelastography, to achieve a final wave speed map by combining reconstructions obtained from all spatial directions and excitation frequencies, the use of weights is inevitable. Here, a new weighting scheme, which maximizes the signal-to-noise ratio (SNR) of the final wave speed map, has been proposed. To maximize the SNR of the final wave speed map, the use of squares of estimated SNR values of reconstructed individual maps has been proposed. Therefore, derivations of the SNR of the reconstructed wave speed maps have become necessary. Considering the noise on the complex MRI signal, the SNR of the reconstructed wave speed map was formulated by an analytical approach assuming a high SNR, and the results were verified using Monte Carlo simulations (MCSs). It has been assumed that the noise remains approximately Gaussian when the image SNR is high enough, despite the nonlinear operations in tomoelastography inversion. Hence, the SNR threshold was determined by comparing the SNR computed by MCSs and analytical approximations. The weighting scheme was evaluated for accuracy, spatial resolution and SNR performances on simulated phantoms. MR elastography (MRE) experiments on two different phantoms were conducted. Wave speed maps were generated for simulated 3D human abdomen MRE data and experimental human abdomen MRE data. The simulation results demonstrated that the SNR-weighted inversion improved the SNR performance of the wave speed map by a factor of two compared to the performance of the original (i.e., amplitude-weighted) reconstruction. In the case of a low SNR, no bias occurred in the wave speed map when SNR weighting was used, whereas 10% bias occurred when the original weighting (i.e., amplitude weighting) was used. Thus, while not altering the accuracy or spatial resolution of the wave speed map with the proposed weighting method, the SNR of the wave speed map has been significantly improved.
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Affiliation(s)
- Cemre Ariyurek
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Bilal Tasdelen
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Yusuf Ziya Ider
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey
| | - Ergin Atalar
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
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Manduca A, Bayly PJ, Ehman RL, Kolipaka A, Royston TJ, Sack I, Sinkus R, Van Beers BE. MR elastography: Principles, guidelines, and terminology. Magn Reson Med 2020; 85:2377-2390. [PMID: 33296103 DOI: 10.1002/mrm.28627] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 10/20/2020] [Accepted: 11/09/2020] [Indexed: 12/13/2022]
Abstract
Magnetic resonance elastography (MRE) is a phase contrast-based MRI technique that can measure displacement due to propagating mechanical waves, from which material properties such as shear modulus can be calculated. Magnetic resonance elastography can be thought of as quantitative, noninvasive palpation. It is increasing in clinical importance, has become widespread in the diagnosis and staging of liver fibrosis, and additional clinical applications are being explored. However, publications have reported MRE results using many different parameters, acquisition techniques, processing methods, and varied nomenclature. The diversity of terminology can lead to confusion (particularly among clinicians) about the meaning of and interpretation of MRE results. This paper was written by the MRE Guidelines Committee, a group formalized at the first meeting of the ISMRM MRE Study Group, to clarify and move toward standardization of MRE nomenclature. The purpose of this paper is to (1) explain MRE terminology and concepts to those not familiar with them, (2) define "good practices" for practitioners of MRE, and (3) identify opportunities to standardize terminology, to avoid confusion.
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Affiliation(s)
- Armando Manduca
- Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Philip J Bayly
- Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Richard L Ehman
- Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Arunark Kolipaka
- Department of Radiology, Ohio State University, Columbus, Ohio, USA
| | - Thomas J Royston
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Ingolf Sack
- Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ralph Sinkus
- Imaging Sciences & Biomedical Engineering, Kings College London, London, United Kingdom
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Wang H, Pednekar A, Tkach JA, Bridgewater KR, Trout AT, Dillman JR, Dumoulin CL. Fusing acceleration and saturation techniques with wave amplitude labeling of time-shifted zeniths MR elastography. Magn Reson Med 2020; 85:1552-1560. [PMID: 32936497 DOI: 10.1002/mrm.28488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/21/2020] [Accepted: 08/03/2020] [Indexed: 12/15/2022]
Abstract
PURPOSE To design a new 2D gradient recalled echo MR elastography (MRE) pulse sequence with inflow saturation for measuring liver stiffness in half the breath-hold time compared to standard of care (SC) 2D GRE MRE sequences. METHODS FASTWALTZ (fusing acceleration and saturation techniques with wave amplitude labeling of time-shifted zeniths) MRE employs an interleaved dual TR strategy with wave amplitude labeling and compressed SENSE undersampling to reduce breath-hold time while incorporating inflow saturation to suppress flow artifacts. The sequence was implemented and compared with SC MRE both in phantoms and in vivo in 5 asymptomatic volunteers. Stiffness values, region of interest size, and breath-hold times were compared between sequences. RESULTS Stiffness values were comparable between FASTWALTZ and SC MRE for both phantoms and in-vivo data. In volunteers, the group mean stiffness values at 60 Hz and region of interest size were 1.96 ± 0.30 kilopascals and 2279 ± 516 mm2 for SC MRE, and 1.95 ± 0.29 kilopascals and 2061 ± 464 mm2 for FASTWALTZ. Breath-hold duration for FASTWALTZ was 6.3 s compared to 13.3 s for SC MRE. CONCLUSION FASTWALTZ provides comparable stiffness values in half the breath-hold time compared to SC MRE and may have clinical benefits in patients with limited breath-holding capacity.
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Affiliation(s)
- Hui Wang
- MR Clinical Science, Philips, Cincinnati, Ohio, USA.,Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Amol Pednekar
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Jean A Tkach
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Kaley R Bridgewater
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Andrew T Trout
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Jonathan R Dillman
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Charles L Dumoulin
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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Kosaka I, Kanazawa Y, Baba K, Hayashi H, Harada M. Quantitative analysis of vibration waves based on Fourier transform in magnetic resonance elastography. Radiol Phys Technol 2020; 13:268-275. [PMID: 32766948 DOI: 10.1007/s12194-020-00579-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 07/29/2020] [Accepted: 07/31/2020] [Indexed: 11/27/2022]
Abstract
We developed a novel magnetic resonance elastography (MRE) analysis method based on Fourier transform to assess the responsive characteristics for different tissue stiffness and degree of transmission of the vibration wave emanating from a passive driver during MRE. A phantom tissue study was conducted with an MRE sequence and vibration wave system using a clinical MR scanner. The phantom tissue consisted of two layers of agar: 0.75 wt% and 1.0 wt%. Phase-unwrapped images derived from acquired MRE phase images were used to generate a phase profile curve, with a line plotted for the phase-unwrapped images. Fourier transform was performed, and the peak value of the power spectrum was derived. The damping rate/ratio was calculated using the Hilbert transform of the phase profile. We found that the mean shear stiffness value of 1.0 wt% agar was higher than that of 0.75 wt% agar. The responsive frequency of the 0.75 wt% agar layer showed a wider range and the damping rate of the signal showed a higher value than the respective values of the 1.0 wt% agar layer. In conclusion, Fourier transform analysis of MRE enabled us to obtain more detailed information of the tissue characteristics and vibration-wave conditions.
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Affiliation(s)
- Ikuho Kosaka
- Radiology Department, Rakuwakai Marutamachi Hospital, Marutamachi-noboru, Shichihonmatsudori, Nakagyo-ku, Kyoto, Kyoto, 604-8401, Japan
| | - Yuki Kanazawa
- Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Toksuhima, Tokushima, 770-8509, Japan.
| | - Kotaro Baba
- National Hospital Organization, 513, Saijocho-ji Temple, Higashihiroshima, Hiroshima, 739-0041, Japan
| | - Hiroaki Hayashi
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 920-0942, Japan
| | - Masafumi Harada
- Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15, Kuramoto-cho, Toksuhima, Tokushima, 770-8509, Japan
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Sui Y, Arani A, Trzasko JD, Murphy MC, Rossman PJ, Glaser KJ, McGee KP, Manduca A, Ehman RL, Araoz PA, Huston J. TURBINE-MRE: A 3D hybrid radial-Cartesian EPI acquisition for MR elastography. Magn Reson Med 2020; 85:945-952. [PMID: 32738084 DOI: 10.1002/mrm.28445] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 07/04/2020] [Accepted: 07/06/2020] [Indexed: 02/06/2023]
Abstract
PURPOSE To develop a novel magnetic resonance elastography (MRE) acquisition using a hybrid radial EPI readout scheme (TURBINE), and to demonstrate its feasibility to obtain wave images and stiffness maps in a phantom and in vivo brain. METHOD The proposed 3D TURBINE-MRE is based on a spoiled gradient-echo MRE sequence with the EPI readout radially rotating about the phase-encoding axis to sample a full 3D k-space. A polyvinyl chloride phantom and 6 volunteers were scanned on a compact 3T GE scanner with a 32-channel head coil at 80 Hz and 60 Hz external vibration, respectively. For comparison, a standard 2D, multislice, spin-echo (SE) EPI-MRE acquisition was also performed with the same motion encoding and resolution. The TURBINE-MRE images were off-line reconstructed with iterative SENSE algorithm. The regional ROI analysis was performed on the 6 volunteers, and the median stiffness values were compared between SE-EPI-MRE and TURBINE-MRE. RESULTS The 3D wave-field images and the generated stiffness maps were comparable between TURBINE-MRE and standard SE-EPI-MRE for the phantom and the volunteers. The Bland-Altman plot showed no significant difference in the median regional stiffness values between the two methods. The stiffness measured with the 2 methods had a strong linear relationship with a Pearson correlation coefficient of 0.943. CONCLUSION We demonstrated the feasibility of the new TURBINE-MRE sequence for acquiring the desired 3D wave-field data and stiffness maps in a phantom and in-vivo brains. This pilot study encourages further exploration of TURBINE-MRE for functional MRE, free-breathing abdominal MRE, and cardiac MRE applications.
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Affiliation(s)
- Yi Sui
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Arvin Arani
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | | | | | | | - Kevin J Glaser
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Kiaran P McGee
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Armando Manduca
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Richard L Ehman
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Philip A Araoz
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - John Huston
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
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33
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Goßmann M, Linder P, Thomas U, Juhasz K, Lemme M, George M, Fertig N, Dragicevic E, Stoelzle-Feix S. Integration of mechanical conditioning into a high throughput contractility assay for cardiac safety assessment. J Pharmacol Toxicol Methods 2020; 105:106892. [PMID: 32629160 DOI: 10.1016/j.vascn.2020.106892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/29/2020] [Accepted: 06/18/2020] [Indexed: 01/10/2023]
Abstract
INDUCTION Despite increasing acceptance of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in safety pharmacology, controversy remains about the physiological relevance of existing in vitro models for their mechanical testing. We hypothesize that existing signs of immaturity of the cell models result from an improper mechanical environment. With the presented study, we aimed at validating the newly developed FLEXcyte96 technology with respect to physiological responses of hiPSC-CMs to pharmacological compounds with known inotropic and/or cardiotoxic effects. METHODS hiPSC-CMs were cultured in a 96-well format on hyperelastic silicone membranes imitating their native mechanical environment. Cardiomyocyte contractility was measured contact-free by application of capacitive displacement sensing of the cell-membrane biohybrids. Acute effects of positive inotropic compounds with distinct mechanisms of action were examined. Additionally, cardiotoxic effects of tyrosine kinase inhibitors and anthracyclines were repetitively examined during repeated exposure to drug concentrations for up to 5 days. RESULTS hiPSC-CMs grown on biomimetic membranes displayed increased contractility responses to isoproterenol, S-Bay K8644 and omecamtiv mecarbil without the need for additional stimulation. Tyrosine kinase inhibitor erlotinib, vandetanib, nilotinib, gefitinib, A-674563 as well as anthracycline idarubicin showed the expected cardiotoxic effects, including negative inotropy and induction of proarrhythmic events. DISCUSSION We conclude that the FLEXcyte 96 system is a reliable high throughput tool for invitro cardiac contractility research, providing the user with data obtained under physiological conditions which resemble the native environment of human heart tissue. We showed that the results obtained for both acute and sub-chronic compound administration are consistent with the respective physiological responses in humans.
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Affiliation(s)
| | - Peter Linder
- innoVitro GmbH, Artilleriestr 2, 52428 Jülich, Germany
| | - Ulrich Thomas
- Nanion Technologies GmbH, Ganghoferstr 70A, 80339 Munich, Germany
| | - Krisztina Juhasz
- Nanion Technologies GmbH, Ganghoferstr 70A, 80339 Munich, Germany; Institute for Nanoelectronics, Technische Universität München, Arcisstrasse 21, 80333 Munich, Germany
| | - Marta Lemme
- Nanion Technologies GmbH, Ganghoferstr 70A, 80339 Munich, Germany
| | - Michael George
- Nanion Technologies GmbH, Ganghoferstr 70A, 80339 Munich, Germany
| | - Niels Fertig
- Nanion Technologies GmbH, Ganghoferstr 70A, 80339 Munich, Germany
| | - Elena Dragicevic
- Nanion Technologies GmbH, Ganghoferstr 70A, 80339 Munich, Germany
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Steady-State Multifrequency Magnetic Resonance Elastography of the Thoracic and Abdominal Human Aorta-Validation and Reference Values. Invest Radiol 2020; 55:451-456. [PMID: 32520515 DOI: 10.1097/rli.0000000000000654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The aim of this study was to investigate the potential of stroboscopic-wavefield-sampling-based multifrequency magnetic resonance elastography (sMRE) for quantifying the stiffness of the human thoracic and abdominal aorta in vivo. MATERIALS AND METHODS The sMRE of the thoracic and abdominal aorta was performed at 1.5 T field strength in 20 healthy volunteers aged 27 to 77 years (3 women; median age, 33 years; interquartile range [IQR], 16 years). Compound maps of shear wave speed (SWS) were reconstructed and evaluated during the diastolic phase in 3 anatomical regions: ascending thoracic aorta (AA), descending thoracic aorta (AD), and abdominal aorta (AAb). The SWS maps were read by 2 readers. Blood pressure and pulse wave velocity were determined noninvasively before sMRE. Data are given as median (IQR) and were compared using the Kruskal-Wallis and Wilcoxon rank sum tests. Intraclass correlation was used to determine interobserver and intraobserver agreement, as well as reproducibility. Multiple linear regression analysis was performed to evaluate effects of age, sex, vessel diameter, blood pressure, pulse wave velocity, and aortic segment on measured SWS. RESULTS All 20 participants underwent successful sMRE, resulting in a total of 60 aortic segments. The median SWS (IQR) of AA, AD, and AAb was 1.62 (0.16) m/s, 2.40 (0.24) m/s, and 2.48 (0.58) m/s, respectively. The SWS in AA was significantly lower (P < 0.001), and no differences in SWS (P = 0.67) were found between AD and AAb. Interobserver and intraobserver agreement, as well as reproducibility, was excellent, with intraclass correlation coefficients ranging between 0.957 and 0.998. A significant but weak influence of age on measured SWS was found, which increased from AA to AD and AAb (R = 0.229, 0.275, 0.377, respectively; P = 0.001-0.005). CONCLUSIONS Quantification of aortic stiffness in different segments of the human aorta is possible with sMRE. Our results correlate well with known aortic stiffness differences in different anatomical locations and demonstrate the potential of sMRE for clinical stiffness measurement of the thoracoabdominal aorta, which may allow detection of physiological variation and cardiovascular diseases.
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Saloux E, Gauthier M, Buklas D, Saplacan V, Denoyer A, Labombarda F, Raitiere O, Criton A, Milliez P, Bauer F. Direct measurement of cardiac stiffness using echocardiographic shearwave imaging during open-chest surgery: A pilot study in human. Echocardiography 2020; 37:722-731. [PMID: 32388915 DOI: 10.1111/echo.14626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 01/30/2020] [Accepted: 02/16/2020] [Indexed: 11/28/2022] Open
Abstract
PURPOSE Cardiac stiffness is a marker of diastolic function with a strong prognostic significance in many heart diseases that is not measurable in clinical practice. This study investigates whether elastometry, a surrogate for organ stiffness, is measurable in the heart using ShearWave Imaging. METHODS In 33 anesthetized patients scheduled for cardiac surgery, ShearWave imaging was acquired epicardially using a dedicated ultrasound machine on the left ventricle parallel to the left anterior descending coronary artery in a loaded heart following the last cardiac beat. Cardiac elastometry was measured offline using the Young modulus with customized software. RESULTS Overall, the ejection fraction was 61 ± 10%. E/A and E/e' ratios were 1.0 ± 0.5 and 10.5 ± 4.1, respectively. Cardiac elastometry averaged 15.3 ± 5.3 kPa with a median of 18 kPa. Patients with high elastometry >18 kPa were older (P = .04), had thicker (P = .02) but smaller LV (P = .004), had larger left atria (P = .05) and a higher BNP level (P = .04). We distinguished three different transmural elastometry patterns: higher epicardial, higher endocardial, or uniformly distributed elastometry. CONCLUSION Elastometry measurement was feasible for the human heart. This surrogate for cardiac stiffness dichotomized patients with low and high elastometry, and provided three different phenotypes of transmural elastometry with link to diastolic function.
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Affiliation(s)
- Eric Saloux
- Department of cardiology and Caen Basse-Normandie University, Caen University Hospital, Caen, France
| | - Michael Gauthier
- Department of cardiology, Caen University Hospital, Caen, France
| | - Dimitrios Buklas
- Department of cardiac surgery, Caen University Hospital, Caen, France
| | - Vladimir Saplacan
- Department of cardiac surgery, Caen University Hospital, Caen, France
| | | | - Fabien Labombarda
- Department of cardiology and Caen Basse-Normandie University, Caen University Hospital, Caen, France
| | - Olivier Raitiere
- Department of cardiology, Rouen University Hospital, Rouen, France
| | | | - Paul Milliez
- Department of cardiology and Caen Basse-Normandie University, Caen University Hospital, Caen, France
| | - Fabrice Bauer
- Pulmonary Hypertension and Advanced Heart Failure Clinic, Department of Cardiac Surgery, INSERM U1096, Rouen University Hospital, Rouen, France
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Schrank F, Warmuth C, Tzschätzsch H, Kreft B, Hirsch S, Braun J, Elgeti T, Sack I. Cardiac-gated steady-state multifrequency magnetic resonance elastography of the brain: Effect of cerebral arterial pulsation on brain viscoelasticity. J Cereb Blood Flow Metab 2020; 40:991-1001. [PMID: 31142226 PMCID: PMC7181097 DOI: 10.1177/0271678x19850936] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 03/29/2019] [Accepted: 04/22/2019] [Indexed: 12/12/2022]
Abstract
In-vivo brain viscoelasticity measured by magnetic resonance elastography (MRE) is a sensitive imaging marker for long-term biophysical changes in brain tissue due to aging and disease; however, it is still unknown whether MRE can reveal short-term periodic alterations of brain viscoelasticity related to cerebral arterial pulsation (CAP). We developed cardiac-gated steady-state MRE (ssMRE) with spiral readout and stroboscopic sampling of continuously induced mechanical vibrations in the brain at 20, 31.25, and 40 Hz frequencies. Maps of magnitude |G*| and phase ϕ of the complex shear modulus were generated by multifrequency dual visco-elasto inversion with a temporal resolution of 40 ms over 4 s. The method was tested in 12 healthy volunteers. During cerebral systole, |G*| decreased by 6.6 ± 1.9% (56 ± 22 Pa, p < 0.001, mean ± SD), whereas ϕ increased by 0.5 ± 0.5% (0.006 ± 0.005 rad, p = 0.002). The effect size of CAP-induced softening slightly decreased with age by 0.10 ± 0.05% per year (p = 0.04), indicating lower cerebral vascular compliance in older individuals. Our data show for the first time that the brain softens and becomes more viscous during systole, possibly due to an effect of CAP-induced arterial expansion and increased blood volume on effective-medium tissue properties. This sensitivity to vascular-solid tissue interactions makes ssMRE potentially useful for detection of cerebral vascular disease.
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Affiliation(s)
- Felix Schrank
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Carsten Warmuth
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Heiko Tzschätzsch
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Bernhard Kreft
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Hirsch
- Berlin Center for Advanced Neuroimaging,
Charité – Universitätsmedizin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics,
Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Thomas Elgeti
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité –
Universitätsmedizin Berlin, Berlin, Germany
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37
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Ito D, Numano T, Ueki T, Habe T, Maeno T, Takamoto K, Igarashi K, Maharjan S, Mizuhara K, Nishijo H. Magnetic resonance elastography of the supraspinatus muscle: A preliminary study on test-retest repeatability and wave quality with different frequencies and image filtering. Magn Reson Imaging 2020; 71:27-36. [PMID: 32325234 DOI: 10.1016/j.mri.2020.04.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 04/13/2020] [Accepted: 04/13/2020] [Indexed: 12/17/2022]
Abstract
The purpose of this study was to determine an optimal condition (vibration frequency and image filtering) for stiffness estimation with high accuracy and stiffness measurement with high repeatability in magnetic resonance elastography (MRE) of the supraspinatus muscle. Nine healthy volunteers underwent two MRE exams separated by at least a 30 min break, on the same day. MRE acquisitions were performed with a gradient-echo type multi-echo MR sequence at 75, 100, and 125 Hz pneumatic vibration. Wave images were processed by a bandpass filter or filter combining bandpass and directional filters (bandpass-directional filter). An observer specified the region of interest (ROI) on clear wave propagation in the supraspinatus muscle, within which the observer measured the stiffness. This study assessed wave image quality according to two indices, as a substitute for the assessment of the accuracy of the stiffness estimation. One is the size of the clear wave propagation area (ROI size used to measure the stiffness) and the other is the qualitative stiffness resolution score in that area. These measurements made by the observer were repeated twice at least one month apart after each MRE exam. This study assessed the intra-examiner and observer repeatability of the stiffness value, ROI size and resolution score in each combination of vibration frequency and image filter. Repeatability of the data was analyzed using the intraclass correlation coefficient (ICC) and 95% limits-of-agreement (LOA) in Bland-Altman analysis. The analyses on intra-examiner and observer repeatability of stiffness indicated that the ICC and 95% LOA were not varied greatly depending on vibration frequency and image filter (intra-examiner repeatability, ICC range, 0.79 to 0.88; 95% LOA range, ±23.95 to ±32.42%, intra-observer repeatability, ICC range, 0.98 to 1.00; 95% LOA range, ±5.10 to ±10.99%). In the analyses on intra-examiner repeatability of ROI size, ICCs were rather low (ranging from: 0.03 to 0.69) while 95% LOA was large in all the combinations of vibration frequency and image filter (ranging from: ±62.66 to ±83.33%). In the analyses on intra-observer repeatability of ROI size, ICCs were sufficiently high in the total combination of vibration frequency and image filter (ranging from 0.80 to 0.87) while the 95% LOAs were better (lower) in the bandpass-directional filter than the bandpass filter (bandpass directional filter vs. bandpass filter, ±28.81 vs. ±54.83% at 75 Hz; ±25.63 vs. ±37.83% at 100 Hz; ±34.51 vs. ±43.36% at 125 Hz). In the analyses on intra-examiner and observer repeatability of resolution score, the mean difference (bias) between the two exams (or observations) was significantly low and there was almost no difference across all the combinations of vibration frequency and image filter (range of bias: -0.11-0.11 and -0.17-0.00, respectively). Additionally, effects of vibration frequency and image filter on wave image quality (ROI size and resolution score) were assessed separately in each exam. Both mean ROI size and resolution score in the bandpass-directional filter were larger than those in the bandpass filter. Among the data in the bandpass-directional filter, mean ROI size was larger at 75 and 100 Hz, and mean resolution score was larger at 100 and 125 Hz. Taking into consideration with the results of repeatability and wave image quality, the present results suggest that optimal vibration frequency and image filter for MRE of the supraspinatus muscles is 100 Hz and bandpass-directional filter, respectively.
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Affiliation(s)
- Daiki Ito
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan; Office of Radiation Technology, Keio University Hospital, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan; Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-2-1, Namiki, Tsukuba-shi, Ibaraki 305-8564, Japan
| | - Tomokazu Numano
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan; Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-2-1, Namiki, Tsukuba-shi, Ibaraki 305-8564, Japan.
| | - Takamichi Ueki
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
| | - Tetsushi Habe
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan; Office of Radiation Technology, Keio University Hospital, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Toshiki Maeno
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
| | - Kouichi Takamoto
- Department of Sport and Health Sciences, Faculty of Human Sciences, University of East Asia, 2-1, Ichinomiyagakuen-cho, Shimonoseki-shi, Yamaguchi 751-8503, Japan; System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630, Sugitani, Toyama 930-0194, Japan
| | - Keisuke Igarashi
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
| | - Surendra Maharjan
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
| | - Kazuyuki Mizuhara
- Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-2-1, Namiki, Tsukuba-shi, Ibaraki 305-8564, Japan; Department of Mechanical Engineering, Tokyo Denki University, 5, Senju Asahicho, Adachi-ku, Tokyo 120-8551, Japan
| | - Hisao Nishijo
- System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630, Sugitani, Toyama 930-0194, Japan
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Majeed W, Kalra P, Kolipaka A. Simultaneous multislice rapid magnetic resonance elastography of the liver. NMR IN BIOMEDICINE 2020; 33:e4252. [PMID: 31971301 PMCID: PMC7286422 DOI: 10.1002/nbm.4252] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 12/09/2019] [Accepted: 12/10/2019] [Indexed: 06/10/2023]
Abstract
To design and validate a rapid Simultaneous Multi-slice (SMS) Magnetic Resonance Elastography technique (MRE), which combines SMS acquisition, in-plane undersampling and an existing rapid Magnetic Resonance Elastography (MREr) scheme to allow accelerated data acquisition in healthy volunteers and comparison against MREr. SMS-MREr sequence was developed by incorporating SMS acquisition scheme into an existing MREr sequence that accelerates MRE acquisition by acquiring data during opposite phases of mechanical vibrations. The MREr sequence accelerated MRE acquisition by acquiring data during opposite phases of mechanical vibrations. Liver MRE was performed on 23 healthy subjects using MREr and SMS-MREr sequences, and mean stiffness values were obtained for manually drawn regions of interest. Linear correlation and agreement between MREr- and SMS-MREr-based stiffness values were investigated. SMS-MREr reduced the scan time by half relative to MREr, and allowed acquisition of four-slice MRE data in a single 17-second breath-hold. Visual comparison suggested agreement between MREr and SMS-MREr elastograms. A Pearson's correlation of 0.93 was observed between stiffness values derived from MREr and SMS-MREr. Bland-Altman analysis demonstrated good agreement, with -0.08 kPa mean bias and narrow limits of agreement (95% CI: 0.23 to -0.39 kPa) between stiffness values obtained using MREr and SMS-MREr. SMS can be combined with other fast MRE approaches to achieve further acceleration. This pushes the limit on the acceleration that can be achieved in MRE acquisition, and makes it possible to conduct liver MRE exams in a single breath-hold.
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Affiliation(s)
- Waqas Majeed
- Department of RadiologyThe Ohio State University Wexner Medical CenterColumbusOhioUSA
| | - Prateek Kalra
- Department of RadiologyThe Ohio State University Wexner Medical CenterColumbusOhioUSA
| | - Arunark Kolipaka
- Department of RadiologyThe Ohio State University Wexner Medical CenterColumbusOhioUSA
- Department of Biomedical EngineeringThe Ohio State UniversityColumbusOhioUSA
- Department of Internal Medicine ‐ Division of CardiologyThe Ohio State University Wexner Medical CenterColumbusOhioUSA
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Guenthner C, Sethi S, Troelstra M, van Gorkum RJ, Gastl M, Sinkus R, Kozerke S. Unipolar MR elastography: Theory, numerical analysis and implementation. NMR IN BIOMEDICINE 2020; 33:e4138. [PMID: 31664745 PMCID: PMC7003474 DOI: 10.1002/nbm.4138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 06/10/2019] [Accepted: 06/14/2019] [Indexed: 06/10/2023]
Abstract
In MR elastography (MRE), zeroth moment balanced motion-encoding gradients (MEGs) are incorporated into MRI sequences to induce a phase shift proportional to the local displacement caused by external actuation. To maximize the signal-to-noise ratio (SNR), fractional encoding is employed, i.e., the MEG duration is reduced below the wave period. Here, gradients encode primarily the velocity of the motion-reducing encoding efficiency. Thus, in GRE-MRE, T2 * decay and motion sensitivity have to be balanced, imposing a lower limit on repetition times (TRs). We propose to use a single trapezoidal gradient, a "unipolar gradient", to directly encode spin displacement. Such gradients cannot be used in conventional sequences as they exhibit a large zeroth moment and dephase magnetization. By time-reversing a spoiled SSFP sequence, the spoiling gradient becomes an efficient unipolar MEG. The proposed "unipolar MRE" technique benefits from this approach in three ways: first, displacement encoding is split over multiple TRs increasing motion sensitivity; second, spoiler and MEG coincide, allowing a reduction in TR; third, motion sensitivity of a typical unipolar lobe is of an order of magnitude higher than a bipolar MEG of equal duration. In this work, motion encoding using unipolar MRE is analyzed using the extended phase graph (EPG) formalism with a periodic motion propagator. As an approximation, the two-transverse TR approximation for diffusion-weighted SSFP is extended to incorporate cyclic motion. A complex encoding efficiency metric is introduced to compare the displacement fields of unipolar and conventional GRE-MRE sequences in both magnitude and phase. The derived theoretical encoding equations are used to characterize the proposed sequence using an extensive parameter study. Unipolar MRE is validated against conventional GRE-MRE in a phantom study showing excellent agreement between measured displacement fields. In addition, unipolar MRE yields significantly increased octahedral shear strain-SNR relative to conventional GRE-MRE and allows for the recovery of high stiffness inclusions, where conventional GRE-MRE fails.
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Affiliation(s)
- Christian Guenthner
- Institute for Biomedical EngineeringUniversity and ETH ZurichZurichSwitzerland
| | - Sweta Sethi
- Division of Research OncologyGuy's and Saint Thomas' NHS Foundation TrustLondonUK
| | - Marian Troelstra
- Division for Imaging Sciences & Biomedical EngineeringKing's College LondonLondonUK
- Department of Radiology and Nuclear MedicineUniversity Medical Center AmsterdamAmsterdamThe Netherlands
| | | | - Mareike Gastl
- Institute for Biomedical EngineeringUniversity and ETH ZurichZurichSwitzerland
| | - Ralph Sinkus
- Division for Imaging Sciences & Biomedical EngineeringKing's College LondonLondonUK
| | - Sebastian Kozerke
- Institute for Biomedical EngineeringUniversity and ETH ZurichZurichSwitzerland
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Schrank F, Warmuth C, Görner S, Meyer T, Tzschätzsch H, Guo J, Uca YO, Elgeti T, Braun J, Sack I. Real‐time MR elastography for viscoelasticity quantification in skeletal muscle during dynamic exercises. Magn Reson Med 2019; 84:103-114. [DOI: 10.1002/mrm.28095] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/29/2019] [Accepted: 11/03/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Felix Schrank
- Department of Radiology Charité–Universitätsmedizin Berlin Berlin Germany
| | - Carsten Warmuth
- Department of Radiology Charité–Universitätsmedizin Berlin Berlin Germany
| | - Steffen Görner
- Department of Radiology Charité–Universitätsmedizin Berlin Berlin Germany
| | - Tom Meyer
- Department of Radiology Charité–Universitätsmedizin Berlin Berlin Germany
| | - Heiko Tzschätzsch
- Department of Radiology Charité–Universitätsmedizin Berlin Berlin Germany
| | - Jing Guo
- Department of Radiology Charité–Universitätsmedizin Berlin Berlin Germany
| | - Yavuz Oguz Uca
- Department of Radiology Charité–Universitätsmedizin Berlin Berlin Germany
| | - Thomas Elgeti
- Department of Radiology Charité–Universitätsmedizin Berlin Berlin Germany
| | - Jürgen Braun
- Institute of Medical Informatics Charité–Universitätsmedizin Berlin Berlin Germany
| | - Ingolf Sack
- Department of Radiology Charité–Universitätsmedizin Berlin Berlin Germany
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Kim DW, Kim SY, Yoon HM, Kim KW, Byun JH. Comparison of technical failure of MR elastography for measuring liver stiffness between gradient‐recalled echo and spin‐echo echo‐planar imaging: A systematic review and meta‐analysis. J Magn Reson Imaging 2019; 51:1086-1102. [DOI: 10.1002/jmri.26918] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 08/14/2019] [Indexed: 12/14/2022] Open
Affiliation(s)
- Dong Wook Kim
- The Department of Radiology and Research Institute of RadiologyUniversity of Ulsan College of Medicine, Asan Medical Center Seoul Republic of Korea
| | - So Yeon Kim
- The Department of Radiology and Research Institute of RadiologyUniversity of Ulsan College of Medicine, Asan Medical Center Seoul Republic of Korea
| | - Hee Mang Yoon
- The Department of Radiology and Research Institute of RadiologyUniversity of Ulsan College of Medicine, Asan Medical Center Seoul Republic of Korea
| | - Kyung Won Kim
- The Department of Radiology and Research Institute of RadiologyUniversity of Ulsan College of Medicine, Asan Medical Center Seoul Republic of Korea
| | - Jae Ho Byun
- The Department of Radiology and Research Institute of RadiologyUniversity of Ulsan College of Medicine, Asan Medical Center Seoul Republic of Korea
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Guenthner C, Sethi S, Troelstra M, Dokumaci AS, Sinkus R, Kozerke S. Ristretto MRE: A generalized multi-shot GRE-MRE sequence. NMR IN BIOMEDICINE 2019; 32:e4049. [PMID: 30697827 PMCID: PMC6590281 DOI: 10.1002/nbm.4049] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/16/2018] [Accepted: 11/09/2018] [Indexed: 05/12/2023]
Abstract
In order to acquire consistent k-space data in MR elastography, a fixed temporal relationship between the MRI sequence and the underlying period of the wave needs to be ensured. To this end, conventional GRE-MRE enforces synchronization through repeated triggering of the transducer and forcing the sequence repetition time to be equal to an integer multiple of the wave period. For wave frequencies below 100 Hz, however, this leads to prolonged acquisition times, as the repetition time scales inversely with frequency. A previously developed multi-shot approach (eXpresso MRE) to multi-slice GRE-MRE tackles this issue by acquiring an integer number of slices per wave period, which allows acquisition to be accelerated in typical scenarios by a factor of two or three. In this work, it is demonstrated that the constraints imposed by the eXpresso scheme are overly restrictive. We propose a generalization of the sequence in three steps by incorporating sequence delays into imaging shots and allowing for interleaved wave-phase acquisition. The Ristretto scheme is compared in terms of imaging shot and total scan duration relative to eXpresso and conventional GRE-MRE and is validated in three different phantom studies. First, the agreement of measured displacement fields in different stages of the sequence generalization is shown. Second, performance is compared for 25, 36, 40, and 60 Hz actuation frequencies. Third, the performance is assessed for the acquisition of different numbers of slices (13 to 17). In vivo feasibility is demonstrated in the liver and the breast. Here, Ristretto is compared with an optimized eXpresso sequence, leading to scan accelerations of 15% and 5%, respectively, without compromising displacement field and stiffness estimates in general. The Ristretto concept allows us to choose imaging shot durations on a fine grid independent of the number of slices and the wave frequency, permitting 2- to 4.5-fold acceleration of conventional GRE-MRE acquisitions.
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Affiliation(s)
- Christian Guenthner
- Institute for Biomedical EngineeringUniversity and ETH ZurichZurichSwitzerland
| | - Sweta Sethi
- Division of Research OncologyGuy's and St Thomas' NHS Foundation TrustLondonUK
| | - Marian Troelstra
- Division of Imaging Sciences & Biomedical EngineeringKing's College LondonLondonUK
- Department of Radiology and Nuclear MedicineAcademic Medical CenterAmsterdamThe Netherlands
| | - Ayse Sila Dokumaci
- Division of Imaging Sciences & Biomedical EngineeringKing's College LondonLondonUK
| | - Ralph Sinkus
- Division of Imaging Sciences & Biomedical EngineeringKing's College LondonLondonUK
| | - Sebastian Kozerke
- Institute for Biomedical EngineeringUniversity and ETH ZurichZurichSwitzerland
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Strasser J, Haindl MT, Stollberger R, Fazekas F, Ropele S. Magnetic resonance elastography of the human brain using a multiphase DENSE acquisition. Magn Reson Med 2019; 81:3578-3587. [PMID: 30693964 PMCID: PMC6590321 DOI: 10.1002/mrm.27672] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/21/2018] [Accepted: 01/04/2019] [Indexed: 11/23/2022]
Abstract
Purpose In magnetic resonance elastography (MRE), a series of time‐shifted images is acquired at specific phase offsets in relation to an induced mechanical excitation. To efficiently gather the set of phase offset images and to overcome limitations due to prolonged TEs and related susceptibility artifacts at low‐frequency MRE, we developed an improved displacement encoding with a stimulated echoes (DENSE) method. Methods The proposed multiphase DENSE‐MRE acquisition scheme allows full sampling of the wave propagation in 1 encoding direction during each TR using multiple readouts at specific phase offsets. With this approach, all phase offsets can be imaged in 1 TR without the need for whole sequence repetitions at time‐shifted offsets relative to the excitation motion. We tested this technique in phantom experiments with 60 Hz and in the brain of 4 volunteers using 20‐Hz harmonic excitation. Results Three‐dimensional wave propagation could be acquired in 7 minutes 30 seconds. Following background phase elimination, clear wave images were obtained, showing the propagation of the waves over time. Calculated shear modulus maps of the phantom matched well to the maps obtained by conventional gradient‐echo MRE. In the brain, low‐frequency DENSE‐MRE images were free of susceptibility‐induced artifacts and the calculated maps showed a median global complex shear modulus magnitude of 0.72 kPa and phase angle of 1.03 rad across volunteers. Conclusion The proposed multiphase DENSE approach allows efficient low‐frequency MRE with short TEs and is well‐suited for low‐frequency MRE of the human brain.
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Affiliation(s)
| | | | - Rudolf Stollberger
- Institute of Medical Engineering, Graz University of Technology, Graz, Austria
| | - Franz Fazekas
- Department of Neurology, Medical University of Graz, Graz, Austria
| | - Stefan Ropele
- Department of Neurology, Medical University of Graz, Graz, Austria
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Kim JK, Yoon H, Lee MJ, Kim MJ, Han K, Koh H, Kim S, Han SJ, Shin HJ. Feasibility of Spin-Echo Echo-Planar Imaging MR Elastography in Livers of Children and Young Adults. ACTA ACUST UNITED AC 2019. [DOI: 10.13104/imri.2019.23.3.251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Jin Kyem Kim
- Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea
| | - Haesung Yoon
- Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea
- Severance Pediatric Liver Disease Research Group, Yonsei University College of Medicine, Seoul, Korea
| | - Mi-Jung Lee
- Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea
- Severance Pediatric Liver Disease Research Group, Yonsei University College of Medicine, Seoul, Korea
| | - Myung-Joon Kim
- Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea
- Severance Pediatric Liver Disease Research Group, Yonsei University College of Medicine, Seoul, Korea
| | - Kyunghwa Han
- Department of Radiology, Research Institute of Radiological Science, Center for Clinical Imaging Data Science, Yonsei University College of Medicine, Seoul, Korea
| | - Hong Koh
- Department of Pediatric Gastroenterology, Hepatology and Nutrition, Yonsei University College of Medicine, Seoul, Korea
- Severance Pediatric Liver Disease Research Group, Yonsei University College of Medicine, Seoul, Korea
| | - Seung Kim
- Department of Pediatric Gastroenterology, Hepatology and Nutrition, Yonsei University College of Medicine, Seoul, Korea
- Severance Pediatric Liver Disease Research Group, Yonsei University College of Medicine, Seoul, Korea
| | - Seok Joo Han
- Department of Pediatric Surgery, Yonsei University College of Medicine, Seoul, Korea
- Severance Pediatric Liver Disease Research Group, Yonsei University College of Medicine, Seoul, Korea
| | - Hyun Joo Shin
- Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea
- Severance Pediatric Liver Disease Research Group, Yonsei University College of Medicine, Seoul, Korea
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Ito D, Numano T, Takamoto K, Ueki T, Habe T, Igarashi K, Mizuhara K, Nishijo H. Simultaneous acquisition of magnetic resonance elastography of the supraspinatus and the trapezius muscles. Magn Reson Imaging 2018; 57:95-102. [PMID: 30465866 DOI: 10.1016/j.mri.2018.11.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/21/2018] [Accepted: 11/17/2018] [Indexed: 01/13/2023]
Abstract
We developed a Magnetic Resonance elastography (MRE) technique using a conventional magnetic resonance imaging (MRI), which allows a simultaneous elastography of the supraspinatus and trapezius muscles, by designing a new wave transducer (vibration pad) and optimizing the mechanical vibration frequency. Five healthy volunteers underwent an MRE. In order to transmit the mechanical vibration (pneumatic vibration) to the supraspinatus and trapezius muscles, a new vibration pad was designed using a three-dimensional (3D) printer. The vibration pad was placed on the skin 2 cm medial and 2 cm cephalad the deltoid tubercle. MRE acquisition was performed with a multi-slice gradient-echo type multi-echo MR sequence, which allows MREs even in a conventional MRI; two oblique axial images of the supraspinatus and trapezius muscles were obtained simultaneously. Vibration frequencies were set at 50-150 Hz, with a 25 Hz step. Wave image quality in each frequency was analyzed using a phase-to-noise ratio (PNR) and clarity of propagating wave that was assessed by two readers qualitatively. In the supraspinatus muscle, the wave images were of good quality especially at frequencies >75 Hz. In the trapezius muscle, the wave images were of better quality at low frequencies (50 and 75 Hz) compared with high frequencies (100-150 Hz). The PNR of both muscles were higher at low frequencies. The mean stiffness in the trapezius muscle (7.26 ± 2.13 kPa at 75 Hz) was larger than those in the supraspinatus muscle (4.16 ± 0.50 kPa at 75 Hz). The results demonstrated that our MRE technique allows simultaneous assessment of the stiffness in the supraspinatus and trapezius muscles using a conventional MRI, and that optimal vibration frequency for simultaneous MRE of these muscles is 75 Hz. This technique provides a new means for early detection of abnormality in the shoulder.
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Affiliation(s)
- Daiki Ito
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan; Office of Radiation Technology, Keio University Hospital, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan; Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-2-1, Namiki, Tsukuba-shi, Ibaraki 305-8564, Japan
| | - Tomokazu Numano
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan; Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-2-1, Namiki, Tsukuba-shi, Ibaraki 305-8564, Japan.
| | - Koichi Takamoto
- System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan
| | - Takamichi Ueki
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
| | - Tetsushi Habe
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
| | - Keisuke Igarashi
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
| | - Kazuyuki Mizuhara
- Department of Mechanical Engineering, Tokyo Denki University, 5, Senju Asahicho, Adachi-ku, Tokyo 120-8551, Japan; Health Research Institute, National Institute of Advanced Industrial Science and Technology, 1-2-1, Namiki, Tsukuba-shi, Ibaraki 305-8564, Japan
| | - Hisao Nishijo
- System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan
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Karpiouk AB, VanderLaan DJ, Larin KV, Emelianov SY. Integrated optical coherence tomography and multielement ultrasound transducer probe for shear wave elasticity imaging of moving tissues. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-7. [PMID: 30369107 PMCID: PMC6210783 DOI: 10.1117/1.jbo.23.10.105006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 09/25/2018] [Indexed: 05/18/2023]
Abstract
Accurate measurements of microelastic properties of soft tissues in-vivo using optical coherence elastography can be affected by motion artifacts caused by cardiac and respiratory cycles. This problem can be overcome using a multielement ultrasound transducer probe where each ultrasound transducer is capable of generating acoustic radiation force (ARF) and, therefore, creating shear waves in tissue. These shear waves, produced during the phase of cardiac and respiratory cycles when tissues are effectively stationary, are detected at the same observation point using phase-sensitive optical coherence tomography (psOCT). Given the known distance between the ultrasound transducers, the speed of shear wave propagation can be calculated by measuring the difference between arrival times of shear waves. The combined multitransducer ARF/psOCT probe has been designed and tested in phantoms and ex-vivo studies using fresh rabbit heart. The measured values of shear moduli are in good agreement with those reported in literature. Our results suggest that the developed multitransducer ARF/psOCT probe can be useful for many in-vivo applications, including quantifying the microelasticity of cardiac muscle.
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Affiliation(s)
- Andrei B. Karpiouk
- Georgia Institute of Technology, Electrical and Computer Engineering Department, Atlanta, Georgia, United States
| | - Donald J. VanderLaan
- Georgia Institute of Technology, Electrical and Computer Engineering Department, Atlanta, Georgia, United States
| | - Kirill V. Larin
- University of Houston, Biomedical Engineering Department, Houston, Texas, United States
- Tomsk State University, Interdisciplinary Laboratory of Biophotonics, Tomsk, Russia
| | - Stanislav Y. Emelianov
- Georgia Institute of Technology, Electrical and Computer Engineering Department, Atlanta, Georgia, United States
- Georgia Institute of Technology and Emory University, School of Medicine, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
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Sinkus R, Lambert S, Abd-Elmoniem KZ, Morse C, Heller T, Guenthner C, Ghanem AM, Holm S, Gharib AM. Rheological determinants for simultaneous staging of hepatic fibrosis and inflammation in patients with chronic liver disease. NMR IN BIOMEDICINE 2018; 31:e3956. [PMID: 30059174 PMCID: PMC6141320 DOI: 10.1002/nbm.3956] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 05/05/2018] [Accepted: 05/07/2018] [Indexed: 05/12/2023]
Abstract
The purpose of this study is to investigate the use of fundamental rheological parameters as quantified by MR elastography (MRE) to measure liver fibrosis and inflammation simultaneously in humans. MRE was performed on 45 patients at 3 T using a vibration frequency of 56 Hz. Fibrosis and inflammation scores were obtained from liver biopsies. Biomechanical properties were quantified in terms of complex shear modulus G* as well as shear wave phase velocity c and shear wave attenuation α. A rheological fractional derivative order model was used to investigate the linear dependence of the free model parameters (dispersion slope y, intrinsic speed c0 , and intrinsic relaxation time τ) on histopathology. Leave-one-out cross-validation was then utilized to demonstrate the effectiveness of the model. The intrinsic speed c0 increases with hepatic fibrosis, while an increased relaxation time τ is reflective of more inflammation of the liver parenchyma. The dispersion slope y does not depend either on fibrosis or on inflammation. The proposed rheological model, given this specific parameterization, establishes the functional dependences of biomechanical parameters on histological fibrosis and inflammation. The leave-one-out cross-validation demonstrates that the model allows identification, from the MRE measurements, of the histology scores when grouped into low-/high-grade fibrosis and low-/high-grade inflammation with significance levels of P = 0.0004 (fibrosis) and P = 0.035 (inflammation). The functional dependences of intrinsic speed and relaxation time on fibrosis and inflammation, respectively, shed new light onto the impact hepatic pathological changes on liver tissue biomechanics in humans. The dispersion slope y appears to represent a structural parameter of liver parenchyma not impacted by the severity of fibrosis/inflammation present in this patient cohort. This specific parametrization of the well-established rheological fractional order model is valuable for the clinical assessment of both fibrosis and inflammation scores, going beyond the capability of the plain shear modulus measurement commonly used for MRE.
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Affiliation(s)
- Ralph Sinkus
- Inserm U1148, LVTS, University Paris Diderot, University Paris 13, Paris, France
- King's College London, BHF Centre of Excellence, Division of Imaging Sciences and Biomedical Engineering, UK
| | - Simon Lambert
- King's College London, BHF Centre of Excellence, Division of Imaging Sciences and Biomedical Engineering, UK
| | - Khaled Z Abd-Elmoniem
- Biomedical and Metabolic Imaging Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Caryn Morse
- Critical Care Medicine Department, NIH Clinical Center, Bethesda, MD, USA
| | - Theo Heller
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Christian Guenthner
- Institute for Biomedical Engineering, University and ETH, Zurich, Zurich, Switzerland
| | - Ahmed M Ghanem
- Biomedical and Metabolic Imaging Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Sverre Holm
- Department of Informatics, University of Oslo, Norway
| | - Ahmed M Gharib
- Biomedical and Metabolic Imaging Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
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Garteiser P, Doblas S, Van Beers BE. Magnetic resonance elastography of liver and spleen: Methods and applications. NMR IN BIOMEDICINE 2018; 31:e3891. [PMID: 29369503 DOI: 10.1002/nbm.3891] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/16/2017] [Accepted: 12/04/2017] [Indexed: 05/06/2023]
Abstract
The viscoelastic properties of the liver and spleen can be assessed with magnetic resonance elastography (MRE). Several actuators, MRI acquisition sequences and reconstruction algorithms have been proposed for this purpose. Reproducible results are obtained, especially when the examination is performed in standard conditions with the patient fasting. Accurate staging of liver fibrosis can be obtained by measuring liver stiffness or elasticity with MRE. Moreover, emerging evidence shows that assessing the tissue viscous parameters with MRE is useful for characterizing liver inflammation, non-alcoholic steatohepatitis, hepatic congestion, portal hypertension, and hepatic tumors. Further advances such as multifrequency acquisitions and compression-sensitive MRE may provide novel quantitative markers of hepatic and splenic mechanical properties that may improve the diagnosis of hepatic and splenic diseases.
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Affiliation(s)
- Philippe Garteiser
- Laboratory of Imaging Biomarkers, Center of Research on Inflammation, UMR 1149 INSERM-University Paris Diderot, Paris, France
| | - Sabrina Doblas
- Laboratory of Imaging Biomarkers, Center of Research on Inflammation, UMR 1149 INSERM-University Paris Diderot, Paris, France
| | - Bernard E Van Beers
- Laboratory of Imaging Biomarkers, Center of Research on Inflammation, UMR 1149 INSERM-University Paris Diderot, Paris, France
- Department of Radiology, Beaujon University Hospital Paris Nord, Clichy, France
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Guenthner C, Kozerke S. Encoding and readout strategies in magnetic resonance elastography. NMR IN BIOMEDICINE 2018; 31:e3919. [PMID: 29806865 DOI: 10.1002/nbm.3919] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 12/15/2017] [Accepted: 02/15/2018] [Indexed: 06/08/2023]
Abstract
Magnetic resonance elastography (MRE) has evolved significantly since its inception. Advances in motion-encoding gradient design and readout strategies have led to improved encoding and signal-to-noise ratio (SNR) efficiencies, which in turn allow for higher spatial resolution, increased coverage, and/or shorter scan times. The purpose of this review is to summarize MRE wave-encoding and readout approaches in a unified mathematical framework to allow for a comparative assessment of encoding and SNR efficiency of the various methods available. Besides standard full- and fractional-wave-encoding approaches, advanced techniques including flow compensation, sample interval modulation and multi-shot encoding are considered. Signal readout using fast k-space trajectories, reduced field of view, multi-slice, and undersampling techniques are summarized and put into perspective. The review is concluded with a foray into displacement and diffusion encoding as alternative and/or complementary techniques.
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Affiliation(s)
- Christian Guenthner
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
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50
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Khan S, Fakhouri F, Majeed W, Kolipaka A. Cardiovascular magnetic resonance elastography: A review. NMR IN BIOMEDICINE 2018; 31:e3853. [PMID: 29193358 PMCID: PMC5975119 DOI: 10.1002/nbm.3853] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/25/2017] [Accepted: 09/29/2017] [Indexed: 05/19/2023]
Abstract
Cardiovascular diseases are the leading cause of death worldwide. These cardiovascular diseases are associated with mechanical changes in the myocardium and aorta. It is known that stiffness is altered in many diseases, including the spectrum of ischemia, diastolic dysfunction, hypertension and hypertrophic cardiomyopathy. In addition, the stiffness of the aortic wall is altered in multiple diseases, including hypertension, coronary artery disease and aortic aneurysm formation. For example, in diastolic dysfunction in which the ejection fraction is preserved, stiffness can potentially be an important biomarker. Similarly, in aortic aneurysms, stiffness can provide valuable information with regard to rupture potential. A number of studies have addressed invasive and non-invasive approaches to test and measure the mechanical properties of the myocardium and aorta. One of the non-invasive approaches is magnetic resonance elastography (MRE). MRE is a phase-contrast magnetic resonance imaging technique that measures tissue stiffness non-invasively. This review article highlights the technical details and application of MRE in the quantification of myocardial and aortic stiffness in different disease states.
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Affiliation(s)
- Saad Khan
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Faisal Fakhouri
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Waqas Majeed
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Arunark Kolipaka
- Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, 43210, USA
- Department of Internal Medicine-Division of Cardiology, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
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