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Shih SF, Wu HH. Free-breathing MRI techniques for fat and R 2* quantification in the liver. MAGMA (NEW YORK, N.Y.) 2024:10.1007/s10334-024-01187-2. [PMID: 39039272 DOI: 10.1007/s10334-024-01187-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 05/18/2024] [Accepted: 07/02/2024] [Indexed: 07/24/2024]
Abstract
OBJECTIVE To review the recent advancements in free-breathing MRI techniques for proton-density fat fraction (PDFF) and R2* quantification in the liver, and discuss the current challenges and future opportunities. MATERIALS AND METHODS This work focused on recent developments of different MRI pulse sequences, motion management strategies, and reconstruction approaches that enable free-breathing liver PDFF and R2* quantification. RESULTS Different free-breathing liver PDFF and R2* quantification techniques have been evaluated in various cohorts, including healthy volunteers and patients with liver diseases, both in adults and children. Initial results demonstrate promising performance with respect to reference measurements. These techniques have a high potential impact on providing a solution to the clinical need of accurate liver fat and iron quantification in populations with limited breath-holding capacity. DISCUSSION As these free-breathing techniques progress toward clinical translation, studies of the linearity, bias, and repeatability of free-breathing PDFF and R2* quantification in a larger cohort are important. Scan acceleration and improved motion management also hold potential for further enhancement.
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Affiliation(s)
- Shu-Fu Shih
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, CA, USA
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Holden H Wu
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA.
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Nosrati R, Calakli F, Afacan O, Pelkola K, Nichols R, Connaughton P, Bedoya MA, Tsai A, Bixby S, Warfield SK. Free-Breathing High-Resolution, Swap-Free, and Motion-Corrected Water/Fat Separation in Pediatric Abdominal MRI. Invest Radiol 2024:00004424-990000000-00221. [PMID: 38857418 DOI: 10.1097/rli.0000000000001092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
OBJECTIVES The T1-weighted GRE (gradient recalled echo) sequence with the Dixon technique for water/fat separation is an essential component of abdominal MRI (magnetic resonance imaging), useful in detecting tumors and characterizing hemorrhage/fat content. Unfortunately, the current implementation of this sequence suffers from several problems: (1) low resolution to maintain high pixel bandwidth and minimize chemical shift; (2) image blurring due to respiratory motion; (3) water/fat swapping due to the natural ambiguity between fat and water peaks; and (4) off-resonance fat blurring due to the multipeak nature of the fat spectrum. The goal of this study was to evaluate the image quality of water/fat separation using a high-resolution 3-point Dixon golden angle radial acquisition with retrospective motion compensation and multipeak fat modeling in children undergoing abdominal MRI. MATERIALS AND METHODS Twenty-two pediatric patients (4.2 ± 2.3 years) underwent abdominal MRI on a 3 T scanner with routine abdominal protocol and with a 3-point Dixon radial-VIBE (volumetric interpolated breath-hold examination) sequence. Field maps were calculated using 3D graph-cut optimization followed by fat and water calculation from k-space data by iteratively solving an optimization problem. A 6-peak fat model was used to model chemical shifts in k-space. Residual respiratory motion was corrected through soft-gating by weighting each projection based on the estimated respiratory motion from the center of the k-space. Reconstructed images were reviewed by 3 pediatric radiologists on a PACS (picture archiving and communication systems) workstation. Subjective image quality and water/fat swapping artifact were scored by each pediatric radiologist using a 5-point Likert scale. The VoL (variance of Laplacian) of the reconstructed images was used to objectively quantify image sharpness. RESULTS Based on the overall Likert scores, the images generated using the described method were significantly superior to those reconstructed by the conventional 2-point Dixon technique (P < 0.05). Water/fat swapping artifact was observed in 14 of 22 patients using 2-point Dixon, and this artifact was not present when using the proposed method. Image sharpness was significantly improved using the proposed framework. CONCLUSIONS In smaller patients, a high-quality water/fat separation with sharp visualization of fine details is critical for diagnostic accuracy. High-resolution golden angle radial-VIBE 3-point Dixon acquisition with 6-peak fat model and soft-gated motion correction offers improved image quality at the expense of an additional ~1-minute acquisition time. Thus, this technique offers the potential to replace the conventional 2-point Dixon technique.
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Affiliation(s)
- Reyhaneh Nosrati
- From the Department of Radiology, Boston Children's Hospital, Boston, MA (R. Nosrati, F.C., O.A., K.P., R. Nichols, P.C., M.A.B., A.T., S.B., S.K.W.); and Harvard Medical School, Boston, MA (R. Nosrati, F.C., O.A., K.P., R. Nichols, P.C., M.A.B., A.T., S.B., S.K.W.)
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Li S, Wang Z, Ding Z, She H, Du YP. Accelerated four-dimensional free-breathing whole-liver water-fat magnetic resonance imaging with deep dictionary learning and chemical shift modeling. Quant Imaging Med Surg 2024; 14:2884-2903. [PMID: 38617145 PMCID: PMC11007520 DOI: 10.21037/qims-23-1396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 02/13/2024] [Indexed: 04/16/2024]
Abstract
Background Multi-echo chemical-shift-encoded magnetic resonance imaging (MRI) has been widely used for fat quantification and fat suppression in clinical liver examinations. Clinical liver water-fat imaging typically requires breath-hold acquisitions, with the free-breathing acquisition method being more desirable for patient comfort. However, the acquisition for free-breathing imaging could take up to several minutes. The purpose of this study is to accelerate four-dimensional free-breathing whole-liver water-fat MRI by jointly using high-dimensional deep dictionary learning and model-guided (MG) reconstruction. Methods A high-dimensional model-guided deep dictionary learning (HMDDL) algorithm is proposed for the acceleration. The HMDDL combines the powers of the high-dimensional dictionary learning neural network (hdDLNN) and the chemical shift model. The neural network utilizes the prior information of the dynamic multi-echo data in spatial respiratory motion, and echo dimensions to exploit the features of images. The chemical shift model is used to guide the reconstruction of field maps, R 2 ∗ maps, water images, and fat images. Data acquired from ten healthy subjects and ten subjects with clinically diagnosed nonalcoholic fatty liver disease (NAFLD) were selected for training. Data acquired from one healthy subject and two NAFLD subjects were selected for validation. Data acquired from five healthy subjects and five NAFLD subjects were selected for testing. A three-dimensional (3D) blipped golden-angle stack-of-stars multi-gradient-echo pulse sequence was designed to accelerate the data acquisition. The retrospectively undersampled data were used for training, and the prospectively undersampled data were used for testing. The performance of the HMDDL was evaluated in comparison with the compressed sensing-based water-fat separation (CS-WF) algorithm and a parallel non-Cartesian recurrent neural network (PNCRNN) algorithm. Results Four-dimensional water-fat images with ten motion states for whole-liver are demonstrated at several R values. In comparison with the CS-WF and PNCRNN, the HMDDL improved the mean peak signal-to-noise ratio (PSNR) of images by 9.93 and 2.20 dB, respectively, and improved the mean structure similarity (SSIM) of images by 0.058 and 0.009, respectively, at R=10. The paired t-test shows that there was no significant difference between HMDDL and ground truth for proton-density fat fraction (PDFF) and R 2 ∗ values at R up to 10. Conclusions The proposed HMDDL enables features of water images and fat images from the highly undersampled multi-echo data along spatial, respiratory motion, and echo dimensions, to improve the performance of accelerated four-dimensional (4D) free-breathing water-fat imaging.
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Affiliation(s)
- Shuo Li
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zhijun Wang
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zekang Ding
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Huajun She
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yiping P Du
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
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Tian Y, Nayak KS. Real-time water/fat imaging at 0.55T with spiral out-in-out-in sampling. Magn Reson Med 2024; 91:649-659. [PMID: 37815020 PMCID: PMC10841523 DOI: 10.1002/mrm.29885] [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: 04/27/2023] [Revised: 08/23/2023] [Accepted: 09/21/2023] [Indexed: 10/11/2023]
Abstract
PURPOSE To develop an efficient and flexible water/fat separated real-time MRI (RT-MRI) method using spiral out-in-out-in (OIOI) sampling and balanced SSFP (bSSFP) at 0.55T. METHODS A bSSFP sequence with golden-angle spiral OIOI readout was developed, capturing three echoes to allow water/fat separation. A low-latency reconstruction that combines all echoes was available for online visualization. An offline reconstruction provided water and fat RT-MRI in two steps: (1) image reconstruction with spatiotemporally constrained reconstruction (STCR) and (2) water/fat separation with hierarchical iterative decomposition of water and fat with echo asymmetry and least-squares estimation (HIDEAL). In healthy volunteers, spiral OIOI was acquired in the wrist during a radial-to-ulnar deviation maneuver, in the heart without breath-hold and cardiac gating, and in the lower abdomen during free-breathing for visualizing small bowel motility. RESULTS We demonstrate successful water/fat separated RT-MRI for all tested applications. In the wrist, resulting images provided clear depiction of ligament gaps and their interactions during the radial-to-ulnar deviation maneuver. In the heart, water/fat RT-MRI depicted epicardial fat, provided improved delineation of epicardial coronary arteries, and provided high blood-myocardial contrast for ventricular function assessment. In the abdomen, water-only RT-MRI captured small bowel mobility clearly with improved water-fat contrast. CONCLUSIONS We have demonstrated a novel and flexible bSSFP spiral OIOI sequence at 0.55T that can provide water/fat separated RT-MRI with a variety of application-specific temporal resolution and spatial resolution requirements.
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Affiliation(s)
- Ye Tian
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
| | - Krishna S. Nayak
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
- Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
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Bano W, Holmes W, Goodburn R, Golbabaee M, Gupta A, Withey S, Tree A, Oelfke U, Wetscherek A. Joint radial trajectory correction for accelerated T 2 * mapping on an MR-Linac. Med Phys 2023; 50:7027-7038. [PMID: 37245075 PMCID: PMC10946747 DOI: 10.1002/mp.16479] [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: 08/04/2022] [Revised: 04/20/2023] [Accepted: 04/28/2023] [Indexed: 05/29/2023] Open
Abstract
BACKGROUND T2 * mapping can characterize tumor hypoxia, which may be associated with resistance to therapy. Acquiring T2 * maps during MR-guided radiotherapy could inform treatment adaptation by, for example, escalating the dose to resistant sub-volumes. PURPOSE The purpose of this work is to demonstrate the feasibility of the accelerated T2 * mapping technique using model-based image reconstruction with integrated trajectory auto-correction (TrACR) for MR-guided radiotherapy on an MR-Linear accelerator (MR-Linac). MATERIALS AND METHODS The proposed method was validated in a numerical phantom, where two T2 * mapping approaches (sequential and joint) were compared for different noise levels (0,0.1,0.5,1) and gradient delays ([1, -1] and [1, -2] in units of dwell time for x- and y-axis, respectively). Fully sampled k-space was retrospectively undersampled using two different undersampling patterns. Root mean square errors (RMSEs) were calculated between reconstructed T2 * maps and ground truth. In vivo data was acquired twice weekly in one prostate and one head and neck cancer patient undergoing treatment on a 1.5 T MR-Linac. Data were retrospectively undersampled and T2 * maps reconstructed, with and without trajectory corrections were compared. RESULTS Numerical simulations demonstrated that, for all noise levels, T2 * maps reconstructed with a joint approach demonstrated less error compared to an uncorrected and sequential approach. For a noise level of 0.1, uniform undersampling and gradient delay [1, -1] (in units of dwell time for x- and y-axis, respectively), RMSEs for sequential and joint approaches were 13.01 and 9.32 ms, respectively, which reduced to 10.92 and 5.89 ms for a gradient delay of [1, 2]. Similarly, for alternate undersampling and gradient delay [1, -1], RMSEs for sequential and joint approaches were 9.80 and 8.90 ms, respectively, which reduced to 9.10 and 5.40 ms for gradient delay [1, 2]. For in vivo data, T2 * maps reconstructed with our proposed approach resulted in less artifacts and improved visual appearance compared to the uncorrected approach. For both prostate and head and neck cancer patients, T2 * maps reconstructed from different treatment fractions showed changes within the planning target volume (PTV). CONCLUSION Using the proposed approach, a retrospective data-driven gradient delay correction can be performed, which is particularly relevant for hybrid devices, where full information on the machine configuration is not available for image reconstruction. T2 * maps were acquired in under 5 min and can be integrated into MR-guided radiotherapy treatment workflows, which minimizes patient burden and leaves time for additional imaging for online adaptive radiotherapy on an MR-Linac.
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Affiliation(s)
- Wajiha Bano
- Joint Department of PhysicsThe Institute of Cancer Research and The Royal Marsden NHS Foundation TrustLondonUK
| | - Will Holmes
- Joint Department of PhysicsThe Institute of Cancer Research and The Royal Marsden NHS Foundation TrustLondonUK
| | - Rosie Goodburn
- Joint Department of PhysicsThe Institute of Cancer Research and The Royal Marsden NHS Foundation TrustLondonUK
| | | | - Amit Gupta
- The Royal Marsden NHS Foundation Trust and The Institute of Cancer ResearchLondonUK
| | - Sam Withey
- The Royal Marsden NHS Foundation Trust and The Institute of Cancer ResearchLondonUK
| | - Alison Tree
- The Royal Marsden NHS Foundation Trust and The Institute of Cancer ResearchLondonUK
| | - Uwe Oelfke
- Joint Department of PhysicsThe Institute of Cancer Research and The Royal Marsden NHS Foundation TrustLondonUK
| | - Andreas Wetscherek
- Joint Department of PhysicsThe Institute of Cancer Research and The Royal Marsden NHS Foundation TrustLondonUK
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Montrazi ET, Bao Q, Martinho RP, Peters DC, Harris T, Sasson K, Agemy L, Scherz A, Frydman L. Deuterium imaging of the Warburg effect at sub-millimolar concentrations by joint processing of the kinetic and spectral dimensions. NMR IN BIOMEDICINE 2023; 36:e4995. [PMID: 37401393 DOI: 10.1002/nbm.4995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/21/2023] [Accepted: 06/03/2023] [Indexed: 07/05/2023]
Abstract
Deuterium metabolic imaging (DMI) is a promising molecular MRI approach, which follows the administration of deuterated substrates and their metabolization. [6,6'-2 H2 ]-glucose for instance is preferentially converted in tumors to [3,3'-2 H2 ]-lactate as a result of the Warburg effect, providing a distinct resonance whose mapping using time-resolved spectroscopic imaging can diagnose cancer. The MR detection of low-concentration metabolites such as lactate, however, is challenging. It has been recently shown that multi-echo balanced steady-state free precession (ME-bSSFP) increases the signal-to-noise ratio (SNR) of these experiments approximately threefold over regular chemical shift imaging; the present study examines how DMI's sensitivity can be increased further by advanced processing methods. Some of these, such as compressed sensing multiplicative denoising and block-matching/3D filtering, can be applied to any spectroscopic/imaging methods. Sensitivity-enhancing approaches were also specifically tailored to ME-bSSFP DMI, by relying on priors related to the resonances' positions and to features of the metabolic kinetics. Two new methods are thus proposed that use these constraints for enhancing the sensitivity of both the spectral images and the metabolic kinetics. The ability of these methods to improve DMI is evidenced in pancreatic cancer studies carried at 15.2 T, where suitable implementations of the proposals imparted eightfold or more SNR improvement over the original ME-bSSFP data, at no informational cost. Comparisons with other propositions in the literature are briefly discussed.
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Affiliation(s)
- Elton T Montrazi
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Qingjia Bao
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China
| | - Ricardo P Martinho
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
- University of Twente, Enschede, The Netherlands
| | - Dana C Peters
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, Connecticut, USA
| | - Talia Harris
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
| | - Keren Sasson
- Department of Plant and Environmental Science, Weizmann Institute of Science, Rehovot, Israel
| | - Lilach Agemy
- Department of Plant and Environmental Science, Weizmann Institute of Science, Rehovot, Israel
| | - Avigdor Scherz
- Department of Plant and Environmental Science, Weizmann Institute of Science, Rehovot, Israel
| | - Lucio Frydman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
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Dimov AV, Li J, Nguyen TD, Roberts AG, Spincemaille P, Straub S, Zun Z, Prince MR, Wang Y. QSM Throughout the Body. J Magn Reson Imaging 2023; 57:1621-1640. [PMID: 36748806 PMCID: PMC10192074 DOI: 10.1002/jmri.28624] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 02/08/2023] Open
Abstract
Magnetic materials in tissue, such as iron, calcium, or collagen, can be studied using quantitative susceptibility mapping (QSM). To date, QSM has been overwhelmingly applied in the brain, but is increasingly utilized outside the brain. QSM relies on the effect of tissue magnetic susceptibility sources on the MR signal phase obtained with gradient echo sequence. However, in the body, the chemical shift of fat present within the region of interest contributes to the MR signal phase as well. Therefore, correcting for the chemical shift effect by means of water-fat separation is essential for body QSM. By employing techniques to compensate for cardiac and respiratory motion artifacts, body QSM has been applied to study liver iron and fibrosis, heart chamber blood and placenta oxygenation, myocardial hemorrhage, atherosclerotic plaque, cartilage, bone, prostate, breast calcification, and kidney stone.
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Affiliation(s)
- Alexey V. Dimov
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Jiahao Li
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Thanh D. Nguyen
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | | | - Pascal Spincemaille
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Sina Straub
- Department of Radiology, Mayo Clinic, Jacksonville, FL, United States
| | - Zungho Zun
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Martin R. Prince
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Yi Wang
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
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Maatman IT, Ypma S, Kachelrieß M, Berker Y, van der Bijl E, Block KT, Hermans JJ, Maas MC, Scheenen TWJ. Single-spoke binning: Reducing motion artifacts in abdominal radial stack-of-stars imaging. Magn Reson Med 2023; 89:1931-1944. [PMID: 36594436 DOI: 10.1002/mrm.29576] [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: 09/21/2022] [Revised: 11/23/2022] [Accepted: 12/19/2022] [Indexed: 01/04/2023]
Abstract
PURPOSE To increase the effectiveness of respiratory gating in radial stack-of-stars MRI, particularly when imaging at high spatial resolutions or with multiple echoes. METHODS Free induction decay (FID) navigators were integrated into a three-dimensional gradient echo radial stack-of-stars pulse sequence. These navigators provided a motion signal with a high temporal resolution, which allowed single-spoke binning (SSB): each spoke at each phase encode step was sorted individually to the corresponding motion state of the respiratory signal. SSB was compared with spoke-angle binning (SAB), in which all phase encode steps of one projection angle were sorted without the use of additional navigator data. To illustrate the benefit of SSB over SAB, images of a motion phantom and of six free-breathing volunteers were reconstructed after motion-gating using either method. Image sharpness was quantitatively compared using image gradient entropies. RESULTS The proposed method resulted in sharper images of the motion phantom and free-breathing volunteers. Differences in gradient entropy were statistically significant (p = 0.03) in favor of SSB. The increased accuracy of motion-gating led to a decrease of streaking artifacts in motion-gated four-dimensional reconstructions. To consistently estimate respiratory signals from the FID-navigator data, specific types of gradient spoiler waveforms were required. CONCLUSION SSB allowed high-resolution motion-corrected MR imaging, even when acquiring multiple gradient echo signals or large acquisition matrices, without sacrificing accuracy of motion-gating. SSB thus relieves restrictions on the choice of pulse sequence parameters, enabling the use of motion-gated radial stack-of-stars MRI in a broader domain of clinical applications.
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Affiliation(s)
- Ivo T Maatman
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sjoerd Ypma
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marc Kachelrieß
- Division of X-Ray Imaging and Computed Tomography, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Yannick Berker
- Hopp Children's Cancer Center Heidelberg (KiTZ), Heidelberg, Germany.,Clinical Cooperation Unit Pediatric Oncology, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, Germany.,National Center for Tumor Diseases (NCT) Heidelberg, Heidelberg, Germany
| | - Erik van der Bijl
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kai Tobias Block
- Department of Radiology, NYU Langone Health, New York, New York, USA
| | - John J Hermans
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marnix C Maas
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Tom W J Scheenen
- Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
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Story JD, Ghahremani S, Kafali SG, Shih SF, Kuwahara KJ, Calkins KL, Wu HH. Using Free-Breathing MRI to Quantify Pancreatic Fat and Investigate Spatial Heterogeneity in Children. J Magn Reson Imaging 2023; 57:508-518. [PMID: 35778376 PMCID: PMC9805469 DOI: 10.1002/jmri.28337] [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] [Received: 04/12/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND MRI acquisition for pediatric pancreatic fat quantification is limited by breath-holds (BH). Full segmentation (FS) or small region of interest (ROI) analysis methods may not account for pancreatic fat spatial heterogeneity, which may limit accuracy. PURPOSE To improve MRI acquisition and analysis for quantifying pancreatic proton-density fat fraction (pPDFF) in children by investigating free-breathing (FB)-MRI, characterizing pPDFF spatial heterogeneity, and relating pPDFF to clinical markers. STUDY TYPE Prospective. POPULATION A total of 34 children, including healthy (N = 16, 8 female) and overweight (N = 18, 5 female) subjects. FIELD STRENGTH AND SEQUENCES 3 T; multiecho gradient-echo three-dimensional (3D) stack-of-stars FB-MRI, multiecho gradient-echo 3D Cartesian BH-MRI. ASSESSMENT A radiologist measured FS- and ROI-based pPDFF on FB-MRI and BH-MRI PDFF maps, with anatomical images as references. Regional pPDFF in the pancreatic head, body, and tail were measured on FB-MRI. FS-pPDFF, ROI-pPDFF, and regional pPDFF were compared, and related to clinical markers, including hemoglobin A1c. STATISTICAL TESTS T-test, Bland-Altman analysis, Lin's concordance correlation coefficient (CCC), one-way analysis of variance, and Spearman's rank correlation coefficient were used. P < 0.05 was considered significant. RESULTS FS-pPDFF and ROI-pPDFF from FB-MRI and BH-MRI had mean difference = 0.4%; CCC was 0.95 for FS-pPDFF and 0.62 for ROI-pPDFF. FS-pPDFF was higher than ROI-pPDFF (10.4% ± 6.4% vs. 4.2% ± 2.8%). Tail-pPDFF (11.6% ± 8.1%) was higher than body-pPDFF (8.9% ± 6.3%) and head-pPDFF (8.7% ± 5.2%). Head-pPDFF and body-pPDFF positively correlated with hemoglobin A1c. DATA CONCLUSION FB-MRI pPDFF is comparable to BH-MRI. Spatial heterogeneity affects pPDFF quantification. Regional measurements of pPDFF in the head and body were correlated with hemoglobin A1c, a marker of insulin sensitivity. EVIDENCE LEVEL 2 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Jacob D. Story
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Shahnaz Ghahremani
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Sevgi Gokce Kafali
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, United States
| | - Shu-Fu Shih
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, United States
| | - Kelsey J. Kuwahara
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Kara L. Calkins
- Department of Pediatrics, Division of Neonatology and Developmental Biology, and the UCLA Children’s Discovery and Innovation Institute, University of California Los Angeles, Los Angeles, CA, United States
| | - Holden H. Wu
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, United States
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Mayer J, Blaszczyk E, Cipriani A, Ferrazzi G, Schulz-Menger J, Schaeffter T, Kolbitsch C. Cardio-respiratory motion-corrected 3D cardiac water-fat MRI using model-based image reconstruction. Magn Reson Med 2022; 88:1561-1574. [PMID: 35775790 DOI: 10.1002/mrm.29284] [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: 09/15/2021] [Revised: 03/04/2022] [Accepted: 04/13/2022] [Indexed: 11/07/2022]
Abstract
PURPOSE Myocardial fat infiltrations are associated with a range of cardiomyopathies. The purpose of this study was to perform cardio-respiratory motion-correction for model-based water-fat separation to image fatty infiltrations of the heart in a free-breathing, non-cardiac-triggered high-resolution 3D MRI acquisition. METHODS Data were acquired in nine patients using a free-breathing, non-cardiac-triggered high-resolution 3D Dixon gradient-echo sequence and radial phase encoding trajectory. Motion correction was combined with a model-based water-fat reconstruction approach. Respiratory and cardiac motion models were estimated using a dual-mode registration algorithm incorporating both motion-resolved water and fat information. Qualitative comparisons of fat structures were made between 2D clinical routine reference scans and reformatted 3D motion-corrected images. To evaluate the effect of motion correction the local sharpness of epicardial fat structures was analyzed for motion-averaged and motion-corrected fat images. RESULTS The reformatted 3D motion-corrected reconstructions yielded qualitatively comparable fat structures and fat structure sharpness in the heart as the standard 2D breath-hold. Respiratory motion correction improved the local sharpness on average by 32% ± 24% with maximum improvements of 81% and cardiac motion correction increased the sharpness further by another 15% ± 11% with maximum increases of 31%. One patient showed a fat infiltration in the myocardium and cardio-respiratory motion correction was able to improve its visualization in 3D. CONCLUSION The 3D water-fat separated cardiac images were acquired during free-breathing and in a clinically feasible and predictable scan time. Compared to a motion-averaged reconstruction an increase in sharpness of fat structures by 51% ± 27% using the presented motion correction approach was observed for nine patients.
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Affiliation(s)
- Johannes Mayer
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Berlin, Germany
| | - Edyta Blaszczyk
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany. HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
- Experimental and Clinical Research Center, a cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- German Center for Cardiovascular Research (DZHK), partner site Berlin, Berlin, Germany
| | - Alberto Cipriani
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany. HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
- Experimental and Clinical Research Center, a cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- German Center for Cardiovascular Research (DZHK), partner site Berlin, Berlin, Germany
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, Padua, Italy
| | | | - Jeanette Schulz-Menger
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany. HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
- Experimental and Clinical Research Center, a cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- German Center for Cardiovascular Research (DZHK), partner site Berlin, Berlin, Germany
| | - Tobias Schaeffter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Berlin, Germany
- Department of Medical Engineering, Technical University of Berlin, Berlin, Germany
| | - Christoph Kolbitsch
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Berlin, Germany
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11
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Li S, Shen C, Ding Z, She H, Du YP. Accelerating multi-echo chemical shift encoded water-fat MRI using model-guided deep learning. Magn Reson Med 2022; 88:1851-1866. [PMID: 35649172 DOI: 10.1002/mrm.29307] [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: 03/17/2022] [Revised: 04/30/2022] [Accepted: 05/02/2022] [Indexed: 11/10/2022]
Abstract
PURPOSE To accelerate chemical shift encoded (CSE) water-fat imaging by applying a model-guided deep learning water-fat separation (MGDL-WF) framework to the undersampled k-space data. METHODS A model-guided deep learning water-fat separation framework is proposed for the acceleration using Cartesian/radial undersampling data. The proposed MGDL-WF combines the power of CSE water-fat imaging model and data-driven deep learning by jointly using a multi-peak fat model and a modified residual U-net network. The model is used to guide the image reconstruction, and the network is used to capture the artifacts induced by the undersampling. A data consistency layer is used in MGDL-WF to ensure the output images to be consistent with the k-space measurements. A Gauss-Newton iteration algorithm is adapted for the gradient updating of the networks. RESULTS Compared with the compressed sensing water-fat separation (CS-WF) algorithm/2-step procedure algorithm, the MGDL-WF increased peak signal-to-noise ratio (PSNR) by 5.31/5.23, 6.11/4.54, and 4.75 dB/1.88 dB with Cartesian sampling, and by 4.13/6.53, 2.90/4.68, and 1.68 dB/3.48 dB with radial sampling, at acceleration rates (R) of 4, 6, and 8, respectively. By using MGDL-WF, radial sampling increased the PSNR by 2.07 dB at R = 8, compared with Cartesian sampling. CONCLUSIONS The proposed MGDL-WF enables exploiting features of the water images and fat images from the undersampled multi-echo data, leading to improved performance in the accelerated CSE water-fat imaging. By using MGDL-WF, radial sampling can further improve the image quality with comparable scan time in comparison with Cartesian sampling.
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Affiliation(s)
- Shuo Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Chenfei Shen
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zekang Ding
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Huajun She
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yiping P Du
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
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12
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Feng L. Golden-Angle Radial MRI: Basics, Advances, and Applications. J Magn Reson Imaging 2022; 56:45-62. [PMID: 35396897 PMCID: PMC9189059 DOI: 10.1002/jmri.28187] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 12/21/2022] Open
Abstract
In recent years, golden‐angle radial sampling has received substantial attention and interest in the magnetic resonance imaging (MRI) community, and it has become a popular sampling trajectory for both research and clinical use. However, although the number of relevant techniques and publications has grown rapidly, there is still a lack of a review paper that provides a comprehensive overview and summary of the basics of golden‐angle rotation, the advantages and challenges/limitations of golden‐angle radial sampling, and recommendations in using different types of golden‐angle radial trajectories for MRI applications. Such a review paper is expected to be helpful both for clinicians who are interested in learning the potential benefits of golden‐angle radial sampling and for MRI physicists who are interested in exploring this research direction. The main purpose of this review paper is thus to present an overview and summary about golden‐angle radial MRI sampling. The review consists of three sections. The first section aims to answer basic questions such as: what is a golden angle; how is the golden angle calculated; why is golden‐angle radial sampling useful, and what are its limitations. The second section aims to review more advanced trajectories of golden‐angle radial sampling, including tiny golden‐angle rotation, stack‐of‐stars golden‐angle radial sampling, and three‐dimensional (3D) kooshball golden‐angle radial sampling. Their respective advantages and limitations and potential solutions to address these limitations are also discussed. Finally, the third section reviews MRI applications that can benefit from golden‐angle radial sampling and provides recommendations to readers who are interested in implementing golden‐angle radial trajectories in their MRI studies.
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Affiliation(s)
- Li Feng
- BioMedical Engineering and Imaging Institute (BMEII) and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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13
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Rasmussen JM, Thompson PM, Entringer S, Buss C, Wadhwa PD. Fetal programming of human energy homeostasis brain networks: Issues and considerations. Obes Rev 2022; 23:e13392. [PMID: 34845821 DOI: 10.1111/obr.13392] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/29/2021] [Accepted: 10/24/2021] [Indexed: 02/07/2023]
Abstract
In this paper, we present a transdisciplinary framework and testable hypotheses regarding the process of fetal programming of energy homeostasis brain circuitry. Our model proposes that key aspects of energy homeostasis brain circuitry already are functional by the time of birth (with substantial interindividual variation); that this phenotypic variation at birth is an important determinant of subsequent susceptibility for energy imbalance and childhood obesity risk; and that this brain circuitry exhibits developmental plasticity, in that it is influenced by conditions during intrauterine life, particularly maternal-placental-fetal endocrine, immune/inflammatory, and metabolic processes and their upstream determinants. We review evidence that supports the scientific premise for each element of this formulation, identify future research directions, particularly recent advances that may facilitate a better quantification of the ontogeny of energy homeostasis brain networks, highlight animal and in vitro-based approaches that may better address the determinants of interindividual variation in energy homeostasis brain networks, and discuss the implications of this formulation for the development of strategies targeted towards the primary prevention of childhood obesity.
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Affiliation(s)
- Jerod M Rasmussen
- Development, Health and Disease Research Program, University of California, Irvine, California, USA.,Department of Pediatrics, University of California, Irvine, California, USA
| | - Paul M Thompson
- Imaging Genetics Center, Mark and Mary Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Sonja Entringer
- Development, Health and Disease Research Program, University of California, Irvine, California, USA.,Department of Pediatrics, University of California, Irvine, California, USA.,Department of Medical Psychology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,Departments of Psychiatry and Human Behavior, Obstetrics and Gynecology, Epidemiology, University of California, Irvine, California, USA
| | - Claudia Buss
- Development, Health and Disease Research Program, University of California, Irvine, California, USA.,Department of Pediatrics, University of California, Irvine, California, USA.,Department of Medical Psychology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.,Departments of Psychiatry and Human Behavior, Obstetrics and Gynecology, Epidemiology, University of California, Irvine, California, USA
| | - Pathik D Wadhwa
- Development, Health and Disease Research Program, University of California, Irvine, California, USA.,Department of Pediatrics, University of California, Irvine, California, USA.,Departments of Psychiatry and Human Behavior, Obstetrics and Gynecology, Epidemiology, University of California, Irvine, California, USA.,Department of Obstetrics and Gynecology, University of California, Irvine, California, USA.,Department of Epidemiology, University of California, Irvine, California, USA
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14
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Dietrich S, Aigner CS, Mayer J, Kolbitsch C, Schulz-Menger J, Schaeffter T, Schmitter S. Motion-compensated fat-water imaging for 3D cardiac MRI at ultra-high fields. Magn Reson Med 2022; 87:2621-2636. [PMID: 35092090 DOI: 10.1002/mrm.29144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 11/23/2021] [Accepted: 12/14/2021] [Indexed: 12/16/2022]
Abstract
PURPOSE Respiratory motion-compensated (MC) 3D cardiac fat-water imaging at 7T. METHODS Free-breathing bipolar 3D triple-echo gradient-recalled-echo (GRE) data with radial phase-encoding (RPE) trajectory were acquired in 11 healthy volunteers (7M\4F, 21-35 years, mean: 30 years) with a wide range of body mass index (BMI; 19.9-34.0 kg/m2 ) and volunteer tailored B 1 + shimming. The bipolar-corrected triple-echo GRE-RPE data were binned into different respiratory phases (self-navigation) and were used for the estimation of non-rigid motion vector fields (MF) and respiratory resolved (RR) maps of the main magnetic field deviations (ΔB0 ). RR ΔB0 maps and MC ΔB0 maps were compared to a reference respiratory phase to assess respiration-induced changes. Subsequently, cardiac binned fat-water images were obtained using a model-based, respiratory motion-corrected image reconstruction. RESULTS The 3D cardiac fat-water imaging at 7T was successfully demonstrated. Local respiration-induced frequency shifts in MC ΔB0 maps are small compared to the chemical shifts used in the multi-peak model. Compared to the reference exhale ΔB0 map these changes are in the order of 10 Hz on average. Cardiac binned MC fat-water reconstruction reduced respiration induced blurring in the fat-water images, and flow artifacts are reduced in the end-diastolic fat-water separated images. CONCLUSION This work demonstrates the feasibility of 3D fat-water imaging at UHF for the entire human heart despite spatial and temporal B 1 + and B0 variations, as well as respiratory and cardiac motion.
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Affiliation(s)
- Sebastian Dietrich
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | | | - Johannes Mayer
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Christoph Kolbitsch
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Jeanette Schulz-Menger
- Experimental and Clinical Research Center, A Joint Cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin, Germany.,Helios Clinics Berlin-Buch Department of Cardiology and Nephrology, Berlin, Germany
| | - Tobias Schaeffter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.,Department of Medical Engineering, Technische Universität Berlin, Germany
| | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA
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15
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Armstrong T, Zhong X, Shih SF, Felker E, Lu DS, Dale BM, Wu HH. Free-breathing 3D stack-of-radial MRI quantification of liver fat and R 2* in adults with fatty liver disease. Magn Reson Imaging 2021; 85:141-152. [PMID: 34662702 DOI: 10.1016/j.mri.2021.10.016] [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: 04/16/2021] [Revised: 10/07/2021] [Accepted: 10/12/2021] [Indexed: 02/07/2023]
Abstract
PURPOSE To investigate the agreement, intra-session repeatability, and inter-reader agreement of liver proton-density fat fraction (PDFF) and R2* quantification using free-breathing 3D stack-of-radial MRI, with and without self-gated motion compensation, compared to reference breath-hold techniques in subjects with fatty liver disease (FLD). METHODS In this institutional review board-approved prospective study, thirty-eight adults with FLD and/or iron overload (24 male, 58 ± 12 years) were imaged at 3T using free-breathing stack-of-radial MRI, breath-hold 3D Cartesian MRI, and breath-hold single-voxel MR spectroscopy (SVS). Each sequence was acquired twice in random order. To assess agreement compared to reference breath-hold techniques, the dependency of liver PDFF and/or R2* quantification on the sequence, radial sampling factor, and radial self-gating temporal resolution was assessed by calculating the Bayesian mean difference (MDB) of the posteriors. Intra-session repeatability and inter-reader agreement (two independent readers) were assessed by the coefficient of repeatability (CR) and intraclass correlation coefficient (ICC), respectively. RESULTS Thirty-five participants (21 male, 57 ± 12 years) were included for analysis. Both free-breathing radial MRI techniques (with and without self-gating) achieved ICC ≥ 0.92 for quantifying PDFF and R2*, and quantified PDFF with MDB < 1.2% compared to breath-hold techniques. Free-breathing radial MRI required self-gating to accurately quantify R2* (MDB < 10s-1 with self-gating; MDB < 50s-1 without self-gating). The radial sampling factor affected PDFF and R2* quantification while the radial self-gating temporal resolution only affected R2* quantification. Repeated self-gated free-breathing radial MRI scans achieved CR < 3% and CR < 27 s-1 for PDFF and R2*, respectively. CONCLUSION A free-breathing stack-of-radial MRI technique with self-gating demonstrated agreement, repeatability, and inter-reader agreement compared to reference breath-hold techniques for quantification of liver PDFF and R2* in adults with FLD.
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Affiliation(s)
- Tess Armstrong
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Xiaodong Zhong
- MR R&D Collaborations, Siemens Medical Solutions USA, Inc., Los Angeles, CA, United States
| | - Shu-Fu Shih
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States; Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, United States
| | - Ely Felker
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - David S Lu
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Brian M Dale
- MR R&D Collaborations, Siemens Medical Solutions USA, Inc., Cary, NC, United States
| | - Holden H Wu
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States; Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, United States.
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16
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Robson PM, Vergani V, Benkert T, Trivieri MG, Karakatsanis NA, Abgral R, Dweck MR, Moreno PR, Kovacic JC, Block KT, Fayad ZA. Assessing the qualitative and quantitative impacts of simple two-class vs multiple tissue-class MR-based attenuation correction for cardiac PET/MR. J Nucl Cardiol 2021; 28:2194-2204. [PMID: 31898004 PMCID: PMC7329599 DOI: 10.1007/s12350-019-02002-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 11/01/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND Hybrid PET/MR imaging has significant potential in cardiology due to its combination of molecular PET imaging and cardiac MR. Multi-tissue-class MR-based attenuation correction (MRAC) is necessary for accurate PET quantification. Moreover, for thoracic PET imaging, respiration is known to lead to misalignments of MRAC and PET data that result in PET artifacts. These factors can be addressed by using multi-echo MR for tissue segmentation and motion-robust or motion-gated acquisitions. However, the combination of these strategies is not routinely available and can be prone to errors. In this study, we examine the qualitative and quantitative impacts of multi-class MRAC compared to a more widely available simple two-class MRAC for cardiac PET/MR. METHODS AND RESULTS In a cohort of patients with cardiac sarcoidosis, we acquired MRAC data using multi-echo radial gradient-echo MR imaging. Water-fat separation was used to produce attenuation maps with up to 4 tissue classes including water-based soft tissue, fat, lung, and background air. Simultaneously acquired 18F-fluorodeoxyglucose PET data were subsequently reconstructed using each attenuation map separately. PET uptake values were measured in the myocardium and compared between different PET images. The inclusion of lung and subcutaneous fat in the MRAC maps significantly affected the quantification of 18F-fluorodeoxyglucose activity in the myocardium but only moderately altered the appearance of the PET image without introduction of image artifacts. CONCLUSION Optimal MRAC for cardiac PET/MR applications should include segmentation of all tissues in combination with compensation for the respiratory-related motion of the heart. Simple two-class MRAC is adequate for qualitative clinical assessment.
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Affiliation(s)
- Philip M Robson
- Translational and Molecular Imaging Institute, Leon and Norma Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, 1470 Madison Ave, TMII - 1st floor, New York, NY, 10029, USA.
| | - Vittoria Vergani
- Translational and Molecular Imaging Institute, Leon and Norma Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, 1470 Madison Ave, TMII - 1st floor, New York, NY, 10029, USA
- Cardiothoracic and Vascular Department, Vita-Salute University and San Raffaele Hospital, Milan, Italy
| | - Thomas Benkert
- Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, NY, USA
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Maria Giovanna Trivieri
- Translational and Molecular Imaging Institute, Leon and Norma Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, 1470 Madison Ave, TMII - 1st floor, New York, NY, 10029, USA
- Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, New York, NY, 10029, USA
| | - Nicolas A Karakatsanis
- Translational and Molecular Imaging Institute, Leon and Norma Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, 1470 Madison Ave, TMII - 1st floor, New York, NY, 10029, USA
- Division of Radiopharmaceutical Sciences, Department of Radiology, Weill Cornell Medical College, Cornell University, New York, NY, USA
| | - Ronan Abgral
- Department of Nuclear Medicine, University Hospital of Brest, European University of Brittany, EA3878 GETBO, Brest, France
| | - Marc R Dweck
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Pedro R Moreno
- Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, New York, NY, 10029, USA
| | - Jason C Kovacic
- Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, New York, NY, 10029, USA
| | - Kai Tobias Block
- Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, NY, USA
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Zahi A Fayad
- Translational and Molecular Imaging Institute, Leon and Norma Hess Center for Science and Medicine, Icahn School of Medicine at Mount Sinai, One Gustave Levy Pl, 1470 Madison Ave, TMII - 1st floor, New York, NY, 10029, USA
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17
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Lassen ML, Slomka PJ. Cardiac PET/MR: Are sophisticated attenuation correction techniques necessary for clinical routine assessments? J Nucl Cardiol 2021; 28:2205-2206. [PMID: 32034663 DOI: 10.1007/s12350-020-02057-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 10/25/2022]
Affiliation(s)
- Martin Lyngby Lassen
- Artificial Intelligence in Medicine Program, Cedars-Sinai Medical Center, 8700 Beverly Blvd. Ste. A047, Los Angeles, CA, 90048, USA.
| | - Piotr J Slomka
- Artificial Intelligence in Medicine Program, Cedars-Sinai Medical Center, 8700 Beverly Blvd. Ste. A047, Los Angeles, CA, 90048, USA
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18
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Glutig K, Mentzel HJ, Prüfer FH, Teichgräber U, Obmann MM, Krämer M. RAVE-T2/T1 - Feasibility of a new hybrid MR-sequence for free-breathing abdominal MRI in children and adolescents. Eur J Radiol 2021; 143:109903. [PMID: 34392003 DOI: 10.1016/j.ejrad.2021.109903] [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: 05/27/2021] [Revised: 07/22/2021] [Accepted: 08/04/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND The new radial volumetric encoding RAVE-T2/T1 hybrid sequence is a modern three-dimensional sequence with multiparametric approach, which includes T2- and T1-weighted contrasts obtained in identical slice position during one measurement. However, the RAVE-T2/T1 hybrid sequence is not yet being used in clinical routine. PURPOSE The aim of this study was to evaluate the RAVE-T2/T1 hybrid sequence in a pediatric population with a clinical indication for an abdominal MRI examination to demonstrate that the hybrid imaging may be less challenging to perform on children. MATERIALS AND METHODS Our retrospective observational study included pediatric patients of all age groups and required for an abdominal MRI examination. Non-contrast standard axial T1 DIXON and non-contrast RAVE-T2/T1 hybrid sequence were obtained at 3 T. MRI studies were analyzed independently by two pediatric radiologists using a 5-point Likert-type scale in five different categories. T1- and T2-weighted sequences were each compared with the RAVE-T2/T1-sequence using a Wilcoxon signed-rank test. RESULTS The analysis included 15 children (mean age, 11 years and 4 months, 7 girls and 8 boys). The Cohens Kappa of interrater agreement measured 0.62. The T2 weighted part of the RAVE-T2/T1 sequence was significantly better than the standard T2 HASTE sequence in four of five image quality categories: overall image quality (2.2 ± 0.7 vs 1.8 ± 0,7, p = 0.03), respiratory motion artefacts (3.8 ± 0.4 vs 2.0 ± 0.7, p <= 0.01), portal vein clarity (3.3 ± 0.8 vs 2.2 ± 0.7, p <= 0.01), hepatic margin sharpness (2.4 ± 1,0 vs 1.8 ± 0.7, p <= 0.01). The T1 weighted part of the RAVE-T2/T1 sequence was significantly better than the standard T1 DIXON weighted sequence in three of five image quality categories: respiratory motion artefacts (4.0 ± 0.2 vs 3.6 ± 0.8, p = 0.01), portal vein clarity (2.7 ± 0.9 vs 2.1 ± 0.7, p <= 0.01), hepatic margin sharpness (3.2 ± 0.7 vs 2.6 ± 0.9, p <= 0.01). CONCLUSIONS The RAVE-T2/T1 hybrid sequence is feasible and equal compared to standard T1- and T2-weighted sequences in the assessment of abdominal organs in a pediatric population. Due to non-inferiority to the current standard sequences for abdominal imaging, the RAVE-T2/T1 hybrid sequence is a good alternative for children who cannot be examined in breath-hold technique.
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Affiliation(s)
- K Glutig
- Jena University Hospital - Friedrich Schiller University Jena, Institute of Diagnostic and Interventional Radiology, Section of Pediatric Radiology, Am Klinikum 1, 07747 Jena, Germany.
| | - H-J Mentzel
- Jena University Hospital - Friedrich Schiller University Jena, Institute of Diagnostic and Interventional Radiology, Section of Pediatric Radiology, Am Klinikum 1, 07747 Jena, Germany
| | - F H Prüfer
- University Children's Hospital UKBB, University of Basel, Paediatric Radiology, Spitalstrasse 33, 4031 Basel, Switzerland
| | - U Teichgräber
- Jena University Hospital - Friedrich Schiller University Jena, Institute of Diagnostic and Interventional Radiology, Section of Pediatric Radiology, Am Klinikum 1, 07747 Jena, Germany
| | - M M Obmann
- University Hospital Basel USB, University of Basel, Clinic of Radiology and Nuclear Medicine, Petersgraben 4, 4031 Basel, Switzerland
| | - M Krämer
- Jena University Hospital - Friedrich Schiller University Jena, Institute of Diagnostic and Interventional Radiology, Section of Pediatric Radiology, Am Klinikum 1, 07747 Jena, Germany
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Feng L, Liu F, Soultanidis G, Liu C, Benkert T, Block KT, Fayad ZA, Yang Y. Magnetization-prepared GRASP MRI for rapid 3D T1 mapping and fat/water-separated T1 mapping. Magn Reson Med 2021; 86:97-114. [PMID: 33580909 PMCID: PMC8197608 DOI: 10.1002/mrm.28679] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 12/22/2022]
Abstract
PURPOSE This study aimed to (i) develop Magnetization-Prepared Golden-angle RAdial Sparse Parallel (MP-GRASP) MRI using a stack-of-stars trajectory for rapid free-breathing T1 mapping and (ii) extend MP-GRASP to multi-echo acquisition (MP-Dixon-GRASP) for fat/water-separated (water-specific) T1 mapping. METHODS An adiabatic non-selective 180° inversion-recovery pulse was added to a gradient-echo-based golden-angle stack-of-stars sequence for magnetization-prepared 3D single-echo or 3D multi-echo acquisition. In combination with subspace-based GRASP-Pro reconstruction, the sequence allows for standard T1 mapping (MP-GRASP) or fat/water-separated T1 mapping (MP-Dixon-GRASP), respectively. The accuracy of T1 mapping using MP-GRASP was evaluated in a phantom and volunteers (brain and liver) against clinically accepted reference methods. The repeatability of T1 estimation was also assessed in the phantom and volunteers. The performance of MP-Dixon-GRASP for water-specific T1 mapping was evaluated in a fat/water phantom and volunteers (brain and liver). RESULTS ROI-based mean T1 values are correlated between the references and MP-GRASP in the phantom (R2 = 1.0), brain (R2 = 0.96), and liver (R2 = 0.73). MP-GRASP achieved good repeatability of T1 estimation in the phantom (R2 = 1.0), brain (R2 = 0.99), and liver (R2 = 0.82). Water-specific T1 is different from in-phase and out-of-phase composite T1 (composite T1 when fat and water signal are mixed in phase or out of phase) both in the phantom and volunteers. CONCLUSION This work demonstrated the initial performance of MP-GRASP and MP-Dixon-GRASP MRI for rapid 3D T1 mapping and 3D fat/water-separated T1 mapping in the brain (without motion) and in the liver (during free breathing). With fat/water-separated T1 estimation, MP-Dixon-GRASP could be potentially useful for imaging patients with fatty-liver diseases.
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Affiliation(s)
- Li Feng
- Biomedical Engineering and Imaging Institute and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Fang Liu
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Georgios Soultanidis
- Biomedical Engineering and Imaging Institute and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Chenyu Liu
- Biomedical Engineering and Imaging Institute and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Thomas Benkert
- MR Application Development, Siemens Healthcare GmbH, Erlangen, Germany
| | - Kai Tobias Block
- MR Application Development, Siemens Healthcare GmbH, Erlangen, Germany
- Center for Advanced Imaging Innovation and Research (CAIR), New York University School of Medicine, New York, NY, USA
| | - Zahi A. Fayad
- Biomedical Engineering and Imaging Institute and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yang Yang
- Biomedical Engineering and Imaging Institute and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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20
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Wang X, Tan Z, Scholand N, Roeloffs V, Uecker M. Physics-based reconstruction methods for magnetic resonance imaging. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20200196. [PMID: 33966457 PMCID: PMC8107652 DOI: 10.1098/rsta.2020.0196] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/01/2021] [Indexed: 05/03/2023]
Abstract
Conventional magnetic resonance imaging (MRI) is hampered by long scan times and only qualitative image contrasts that prohibit a direct comparison between different systems. To address these limitations, model-based reconstructions explicitly model the physical laws that govern the MRI signal generation. By formulating image reconstruction as an inverse problem, quantitative maps of the underlying physical parameters can then be extracted directly from efficiently acquired k-space signals without intermediate image reconstruction-addressing both shortcomings of conventional MRI at the same time. This review will discuss basic concepts of model-based reconstructions and report on our experience in developing several model-based methods over the last decade using selected examples that are provided complete with data and code. This article is part of the theme issue 'Synergistic tomographic image reconstruction: part 1'.
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Affiliation(s)
- Xiaoqing Wang
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Göttingen, Germany
- Partner Site Göttingen, German Centre for Cardiovascular Research (DZHK), Göttingen, Germany
| | - Zhengguo Tan
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Göttingen, Germany
- Partner Site Göttingen, German Centre for Cardiovascular Research (DZHK), Göttingen, Germany
| | - Nick Scholand
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Göttingen, Germany
- Partner Site Göttingen, German Centre for Cardiovascular Research (DZHK), Göttingen, Germany
| | - Volkert Roeloffs
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Göttingen, Germany
| | - Martin Uecker
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Göttingen, Germany
- Partner Site Göttingen, German Centre for Cardiovascular Research (DZHK), Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells’ (MBExC), University of Göttingen, Göttingen, Germany
- Campus Institute Data Science (CIDAS), University of Göttingen, Göttingen, Germany
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21
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Giza SA, Koreman TL, Sethi S, Miller MR, Penava DA, Eastabrook GD, McKenzie CA, de Vrijer B. Water-fat magnetic resonance imaging of adipose tissue compartments in the normal third trimester fetus. Pediatr Radiol 2021; 51:1214-1222. [PMID: 33512538 DOI: 10.1007/s00247-020-04955-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 10/21/2020] [Accepted: 12/20/2020] [Indexed: 01/10/2023]
Abstract
BACKGROUND Assessment of fetal adipose tissue gives information about the future metabolic health of an individual, with evidence that the development of this tissue has regional heterogeneity. OBJECTIVE To assess differences in the proton density fat fraction (PDFF) between fetal adipose tissue compartments in the third trimester using water-fat magnetic resonance imaging (MRI). MATERIALS AND METHODS Water-fat MRI was performed in a 1.5-T scanner. Fetal adipose tissue was segmented into cheeks, thorax, abdomen, upper arms, forearms, thighs and lower legs. PDFF and R2* values were measured in each compartment. RESULTS Twenty-eight women with singleton pregnancies were imaged between 28 and 38 weeks of gestation. At 30 weeks' gestation (n=22), the PDFF was statistically different between the compartments (P<0.0001), with the highest PDFF in cheeks, followed by upper arms, thorax, thighs, forearms, lower legs and abdomen. There were no statistical differences in the rate of PDFF change with gestational age between the white adipose tissue compartments (P=0.97). Perirenal brown adipose tissue had a different PDFF and R2* compared to white adipose tissue, while the rate of R2* change did not significantly change with gestational age between white adipose tissue compartments (P=0.96). CONCLUSION Fetal adipose tissue accumulates lipids at a similar rate in all white adipose tissue compartments. PDFF variances between the compartments suggest that accumulation begins at different gestational ages, starting with cheeks, followed by extremities, trunk and abdomen. Additionally, MRI was able to detect differences in the PDFF between fetal brown adipose tissue and white adipose tissue.
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Affiliation(s)
- Stephanie A Giza
- Department of Medical Biophysics, Western University, London, ON, Canada
| | - Tianna L Koreman
- Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Simran Sethi
- Department of Medical Biophysics, Western University, London, ON, Canada
| | - Michael R Miller
- Division of Maternal, Fetal and Newborn Health, Children's Health Research Institute, London Health Sciences Centre, Victoria Hospital, 800 Commissioner's Road E, Room B2-412, London, ON, N6A 3B4, Canada.,Department of Paediatrics, Western University, London, ON, Canada
| | - Debbie A Penava
- Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Division of Maternal, Fetal and Newborn Health, Children's Health Research Institute, London Health Sciences Centre, Victoria Hospital, 800 Commissioner's Road E, Room B2-412, London, ON, N6A 3B4, Canada.,Department of Obstetrics and Gynaecology, Western University, London, ON, Canada
| | - Genevieve D Eastabrook
- Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Division of Maternal, Fetal and Newborn Health, Children's Health Research Institute, London Health Sciences Centre, Victoria Hospital, 800 Commissioner's Road E, Room B2-412, London, ON, N6A 3B4, Canada.,Department of Obstetrics and Gynaecology, Western University, London, ON, Canada
| | - Charles A McKenzie
- Department of Medical Biophysics, Western University, London, ON, Canada.,Division of Maternal, Fetal and Newborn Health, Children's Health Research Institute, London Health Sciences Centre, Victoria Hospital, 800 Commissioner's Road E, Room B2-412, London, ON, N6A 3B4, Canada
| | - Barbra de Vrijer
- Schulich School of Medicine and Dentistry, Western University, London, ON, Canada. .,Division of Maternal, Fetal and Newborn Health, Children's Health Research Institute, London Health Sciences Centre, Victoria Hospital, 800 Commissioner's Road E, Room B2-412, London, ON, N6A 3B4, Canada. .,Department of Obstetrics and Gynaecology, Western University, London, ON, Canada.
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22
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Xiao Z, Du N, Liu J, Zhang W. SR-Net: A sequence offset fusion net and refine net for undersampled multislice MR image reconstruction. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 202:105997. [PMID: 33621943 DOI: 10.1016/j.cmpb.2021.105997] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 02/06/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE The study of deep learning-based fast magnetic resonance imaging (MRI) reconstruction methods has become popular in recent years. However, there is still a challenge when MRI results undersample large acceleration factors. The objective of this study was to improve the reconstruction quality of undersampled MR images by exploring data redundancy among slices. METHODS There are two aspects of redundancy in multislice MR images including correlations inside a single slice and correlations among slices. Thus, we built two subnets for the two kinds of redundancy. For correlations among slices, we built a bidirectional recurrent convolutional neural network, named Sequence Offset Fusion Net (S-Net). In S-Net, we used a deformable convolution module to construct a neighbor slice feature extractor. For the correlation inside a single slice, we built a Refine Net (R-Net), which has 5 layers of 2D convolutions. In addition, we used a data consistency (DC) operation to maintain data fidelity in k-space. Finally, we treated the reconstruction task as a dealiasing problem in the image domain, and S-Net and R-Net are applied alternately and iteratively to generate the final reconstructions. RESULTS The proposed algorithm was evaluated using two online public MRI datasets. Compared with several state-of-the-art methods, the proposed method achieved better reconstruction results in terms of dealiasing and restoring tissue structure. Moreover, with over 14 slices per second reconstruction speed on 256x256 pixel images, the proposed method can meet the need for real-time processing. CONCLUSION With spatial correlation among slices as additional prior information, the proposed method dramatically improves the reconstruction quality of undersampled MR images.
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Affiliation(s)
- Zhiyong Xiao
- School of Artificial Intelligence and Computer Science, Jiangnan University, Wuxi 214122, China.
| | - Nianmao Du
- School of Artificial Intelligence and Computer Science, Jiangnan University, Wuxi 214122, China
| | - Jianjun Liu
- School of Artificial Intelligence and Computer Science, Jiangnan University, Wuxi 214122, China
| | - Weidong Zhang
- Department of Automation, Shanghai JiaoTong University, Shanghai 200240, China.
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23
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Mayer J, Wurster TH, Schaeffter T, Landmesser U, Morguet A, Bigalke B, Hamm B, Brenner W, Makowski MR, Kolbitsch C. Imaging coronary plaques using 3D motion-compensated [ 18F]NaF PET/MR. Eur J Nucl Med Mol Imaging 2021; 48:2455-2465. [PMID: 33474584 PMCID: PMC8241750 DOI: 10.1007/s00259-020-05180-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/26/2020] [Indexed: 12/19/2022]
Abstract
Background Cardiac PET has recently found novel applications in coronary atherosclerosis imaging using [18F]NaF as a radiotracer, highlighting vulnerable plaques. However, the resulting uptakes are relatively small, and cardiac motion and respiration-induced movement of the heart can impair the reconstructed images due to motion blurring and attenuation correction mismatches. This study aimed to apply an MR-based motion compensation framework to [18F]NaF data yielding high-resolution motion-compensated PET and MR images. Methods Free-breathing 3-dimensional Dixon MR data were acquired, retrospectively binned into multiple respiratory and cardiac motion states, and split into fat and water fraction using a model-based reconstruction framework. From the dynamic MR reconstructions, both a non-rigid cardiorespiratory motion model and a motion-resolved attenuation map were generated and applied to the PET data to improve image quality. The approach was tested in 10 patients and focal tracer hotspots were evaluated concerning their target-to-background ratio, contrast-to-background ratio, and their diameter. Results MR-based motion models were successfully applied to compensate for physiological motion in both PET and MR. Target-to-background ratios of identified plaques improved by 7 ± 7%, contrast-to-background ratios by 26 ± 38%, and the plaque diameter decreased by −22 ± 18%. MR-based dynamic attenuation correction strongly reduced attenuation correction artefacts and was not affected by stent-related signal voids in the underlying MR reconstructions. Conclusions The MR-based motion correction framework presented here can improve the target-to-background, contrast-to-background, and width of focal tracer hotspots in the coronary system. The dynamic attenuation correction could effectively mitigate the risk of attenuation correction artefacts in the coronaries at the lung-soft tissue boundary. In combination, this could enable a more reproducible and reliable plaque localisation. Supplementary Information The online version contains supplementary material available at 10.1007/s00259-020-05180-4.
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Affiliation(s)
- Johannes Mayer
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Berlin, Germany.
| | - Thomas-Heinrich Wurster
- Klinik für Kardiologie, Charité Campus Benjamin Franklin, Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany
| | - Tobias Schaeffter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Berlin, Germany.,School of Biomedical Imaging Sciences, King's College London, London, UK.,Department of Medical Engineering, Technische Universität Berlin, Berlin, Germany
| | - Ulf Landmesser
- Klinik für Kardiologie, Charité Campus Benjamin Franklin, Universitätsmedizin Berlin, Berlin, Germany
| | - Andreas Morguet
- Klinik für Kardiologie, Charité Campus Benjamin Franklin, Universitätsmedizin Berlin, Berlin, Germany
| | - Boris Bigalke
- Klinik für Kardiologie, Charité Campus Benjamin Franklin, Universitätsmedizin Berlin, Berlin, Germany
| | - Bernd Hamm
- Department of Radiology, Charité, Universitätsmedizin Berlin, Berlin, Germany
| | - Winfried Brenner
- Department of Nuclear Medicine, Charité, Universitätsmedizin Berlin, Berlin, Germany
| | - Marcus R Makowski
- Department of Medical Engineering, Technische Universität Berlin, Berlin, Germany.,Department of Radiology, Klinikum Rechts der Isar, Technische Universität München, München, Germany
| | - Christoph Kolbitsch
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Berlin, Germany.,School of Biomedical Imaging Sciences, King's College London, London, UK
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24
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The application of in utero magnetic resonance imaging in the study of the metabolic and cardiovascular consequences of the developmental origins of health and disease. J Dev Orig Health Dis 2020; 12:193-202. [PMID: 33308364 PMCID: PMC8162788 DOI: 10.1017/s2040174420001154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Observing fetal development in utero is vital to further the understanding of later-life diseases. Magnetic resonance imaging (MRI) offers a tool for obtaining a wealth of information about fetal growth, development, and programming not previously available using other methods. This review provides an overview of MRI techniques used to investigate the metabolic and cardiovascular consequences of the developmental origins of health and disease (DOHaD) hypothesis. These methods add to the understanding of the developing fetus by examining fetal growth and organ development, adipose tissue and body composition, fetal oximetry, placental microstructure, diffusion, perfusion, flow, and metabolism. MRI assessment of fetal growth, organ development, metabolism, and the amount of fetal adipose tissue could give early indicators of abnormal fetal development. Noninvasive fetal oximetry can accurately measure placental and fetal oxygenation, which improves current knowledge on placental function. Additionally, measuring deficiencies in the placenta’s transport of nutrients and oxygen is critical for optimizing treatment. Overall, the detailed structural and functional information provided by MRI is valuable in guiding future investigations of DOHaD.
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25
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Solomon E, Rigie DS, Vahle T, Paška J, Bollenbeck J, Sodickson DK, Boada FE, Block KT, Chandarana H. Free-breathing radial imaging using a pilot-tone radiofrequency transmitter for detection of respiratory motion. Magn Reson Med 2020; 85:2672-2685. [PMID: 33306216 DOI: 10.1002/mrm.28616] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/14/2020] [Accepted: 11/05/2020] [Indexed: 12/21/2022]
Abstract
PURPOSE To describe an approach for detection of respiratory signals using a transmitted radiofrequency (RF) reference signal called Pilot-Tone (PT) and to use the PT signal for creation of motion-resolved images based on 3D stack-of-stars imaging under free-breathing conditions. METHODS This work explores the use of a reference RF signal generated by a small RF transmitter, placed outside the MR bore. The reference signal is received in parallel to the MR signal during each readout. Because the received PT amplitude is modulated by the subject's breathing pattern, a respiratory signal can be obtained by detecting the strength of the received PT signal over time. The breathing-induced PT signal modulation can then be used for reconstructing motion-resolved images from free-breathing scans. The PT approach was tested in volunteers using a radial stack-of-stars 3D gradient echo (GRE) sequence with golden-angle acquisition. RESULTS Respiratory signals derived from the proposed PT method were compared to signals from a respiratory cushion sensor and k-space-center-based self-navigation under different breathing conditions. Moreover, the accuracy was assessed using a modified acquisition scheme replacing the golden-angle scheme by a zero-angle acquisition. Incorporating the PT signal into eXtra-Dimensional (XD) motion-resolved reconstruction led to improved image quality and clearer anatomical depiction of the lung and liver compared to k-space-center signal and motion-averaged reconstruction, when binned into 6, 8, and 10 motion states. CONCLUSION PT is a novel concept for tracking respiratory motion. Its small dimension (8 cm), high sampling rate, and minimal interaction with the imaging scan offers great potential for resolving respiratory motion.
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Affiliation(s)
- Eddy Solomon
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA
| | - David S Rigie
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA
| | | | - Jan Paška
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA
| | | | - Daniel K Sodickson
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Fernando E Boada
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Kai Tobias Block
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA.,Siemens Healthcare GmbH, Erlangen, Germany
| | - Hersh Chandarana
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA
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26
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Respiratory Motion Detection and Correction for MR Using the Pilot Tone: Applications for MR and Simultaneous PET/MR Examinations. Invest Radiol 2020; 55:153-159. [PMID: 31895221 DOI: 10.1097/rli.0000000000000619] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The aim of this study was to develop a method for tracking respiratory motion throughout full MR or PET/MR studies that requires only minimal additional hardware and no modifications to the sequences. MATERIALS AND METHODS Patient motion that is caused by respiration affects the quality of the signal of the individual radiofrequency receive coil elements. This effect can be detected as a modulation of a monofrequent signal that is emitted by a small portable transmitter placed inside the bore (Pilot Tone). The frequency is selected such that it is located outside of the frequency band of the actual MR readout experiment but well within the bandwidth of the radiofrequency receiver, that is, the oversampling area. Temporal variations of the detected signal indicate motion. After extraction of the signal from the raw data, principal component analysis was used to identify respiratory motion. The approach and potential applications during MR and PET/MR examinations that rely on a continuous respiratory signal were validated with an anthropomorphic, PET/MR-compatible motion phantom as well as in a volunteer study. RESULTS Respiratory motion detection and correction were presented for MR and PET data in phantom and volunteer studies. The Pilot Tone successfully recovered the ground-truth respiratory signal provided by the phantom. CONCLUSIONS The presented method provides reliable respiratory motion tracking during arbitrary imaging sequences throughout a full PET/MR study. All results can directly be transferred to MR-only applications as well.
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27
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de Gouw DJJM, Maas MC, Slagt C, Mühling J, Nakamoto A, Klarenbeek BR, Rosman C, Hermans JJ, Scheenen TWJ. Controlled mechanical ventilation to detect regional lymph node metastases in esophageal cancer using USPIO-enhanced MRI; comparison of image quality. Magn Reson Imaging 2020; 74:258-265. [PMID: 32976957 DOI: 10.1016/j.mri.2020.09.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 09/08/2020] [Accepted: 09/20/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND Artifacts caused by respiratory motion or ventilation-induced chest movements are a major problem for thoracic MRI, as they can obscure important anatomical structures such as lymph node metastases. We compared image quality of routine breathhold with intermittent apnea during controlled mechanical ventilation of patients under general anesthesia as the ideal situation without respiratory motion in the detection and characterization of regional lymph nodes in esophageal cancer. METHODS In this prospective study, 10 patients treated for esophageal cancer underwent ultrasmall superparamagnetic iron oxide (USPIO) enhanced MRI scans. Before neoadjuvant therapy, MRI scans were acquired with a routine breathhold technique. After neoadjuvant therapy, patients were scanned under general anesthesia immediately prior to surgery with controlled mechanical ventilation. The image quality was compared using a Likert scale questionnaire based on visibility of anatomical structures and image artifacts. RESULTS MRI with controlled mechanical ventilation and prolonged controlled apnea of 4 min was safe and feasible. All cardio-respiratory monitoring parameters remained stable during the apnea phases. Mediastinal and upper abdominal lymph nodes down to 2 mm in size could be visualized with all sequences. All image quality criteria, including visibility of thoracic structures and regional lymph nodes were scored higher using the controlled ventilation sequences compared to the routine breathhold phase. CONCLUSION USPIO-enhanced MRI with controlled mechanical ventilation is superior to routine breathhold MRI in visualizing lymph nodes, which warrants new motion reduction techniques to use MRI for the detection of lymph node metastases in patients with esophageal cancer.
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Affiliation(s)
- D J J M de Gouw
- Radboud University Medical Center, Department of Surgery, Nijmegen, the Netherlands.
| | - M C Maas
- Radboud University Medical Center, Department of Medical Imaging, Nijmegen, the Netherlands.
| | - C Slagt
- Radboud University Medical Center, Department of Anesthesiology, Pain and Palliative Medicine, Nijmegen, the Netherlands.
| | - J Mühling
- Radboud University Medical Center, Department of Anesthesiology, Pain and Palliative Medicine, Nijmegen, the Netherlands.
| | - A Nakamoto
- Osaka University Graduate School of Medicine, Department of Radiology, Suita, Japan.
| | - B R Klarenbeek
- Radboud University Medical Center, Department of Surgery, Nijmegen, the Netherlands.
| | - C Rosman
- Radboud University Medical Center, Department of Surgery, Nijmegen, the Netherlands.
| | - J J Hermans
- Radboud University Medical Center, Department of Medical Imaging, Nijmegen, the Netherlands.
| | - T W J Scheenen
- Radboud University Medical Center, Department of Medical Imaging, Nijmegen, the Netherlands.
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28
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Huang J, Chen L, Chan KWY, Cai C, Cai S, Chen Z. Super-resolved water/fat image reconstruction based on single-shot spatiotemporally encoded MRI. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 314:106736. [PMID: 32361511 DOI: 10.1016/j.jmr.2020.106736] [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: 12/26/2019] [Revised: 04/11/2020] [Accepted: 04/18/2020] [Indexed: 06/11/2023]
Abstract
Single-shot spatiotemporally encoded (SPEN) MRI has been validated to possess considerable performance in both spatial and temporal resolution. Water/fat separation is essential for MRI applications in which only water signal is needed. In this article, a super-resolved water/fat image reconstruction method (dubbed SWAF) combined prior knowledge was developed based on single-shot SPEN MRI. The point spread function of spatiotemporal encoding under multiple chemical shifts situation was derived and used for constructing an equation for SWAF image reconstruction. By processing the prior chemical shift information with filtering operation, an initial spin density profile of water/fat and a weighting matrix for water/fat residual artifacts suppression were obtained to guide the reconstruction process. A l1 norm minimization problem with regularization was exploited to reconstruct separated water/fat images with high spatial resolution and less residual/aliasing artifacts. Numeric simulation and experiments on water-oil phantom and rat abdomen/neck imaging demonstrated the effectiveness and robustness of this new method. The SWAF method proposed herein would promote the application of SPEN MRI in the cases where water/fat separation is required.
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Affiliation(s)
- Jianpan Huang
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China; Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Lin Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
| | - Kannie W Y Chan
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Congbo Cai
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China.
| | - Shuhui Cai
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China.
| | - Zhong Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China
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29
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Schneider M, Benkert T, Solomon E, Nickel D, Fenchel M, Kiefer B, Maier A, Chandarana H, Block KT. Free-breathing fat and R 2 * quantification in the liver using a stack-of-stars multi-echo acquisition with respiratory-resolved model-based reconstruction. Magn Reson Med 2020; 84:2592-2605. [PMID: 32301168 PMCID: PMC7396291 DOI: 10.1002/mrm.28280] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 03/22/2020] [Accepted: 03/23/2020] [Indexed: 01/04/2023]
Abstract
Purpose To develop a free‐breathing hepatic fat and
R2∗ quantification method by extending a previously described stack‐of‐stars model‐based fat‐water separation technique with additional modeling of the transverse relaxation rate
R2∗. Methods The proposed technique combines motion‐robust radial sampling using a stack‐of‐stars bipolar multi‐echo 3D GRE acquisition with iterative model‐based fat‐water separation. Parallel‐Imaging and Compressed‐Sensing principles are incorporated through modeling of the coil‐sensitivity profiles and enforcement of total‐variation (TV) sparsity on estimated water, fat, and
R2∗ parameter maps. Water and fat signals are used to estimate the confounder‐corrected proton‐density fat fraction (PDFF). Two strategies for handling respiratory motion are described: motion‐averaged and motion‐resolved reconstruction. Both techniques were evaluated in patients (n = 14) undergoing a hepatobiliary research protocol at 3T. PDFF and
R2∗ parameter maps were compared to a breath‐holding Cartesian reference approach. Results Linear regression analyses demonstrated strong (r > 0.96) and significant (P ≪ .01) correlations between radial and Cartesian PDFF measurements for both the motion‐averaged reconstruction (slope: 0.90; intercept: 0.07%) and the motion‐resolved reconstruction (slope: 0.90; intercept: 0.11%). The motion‐averaged technique overestimated hepatic
R2∗ values (slope: 0.35; intercept: 30.2 1/s) compared to the Cartesian reference. However, performing a respiratory‐resolved reconstruction led to better
R2∗ value consistency (slope: 0.77; intercept: 7.5 1/s). Conclusions The proposed techniques are promising alternatives to conventional Cartesian imaging for fat and
R2∗ quantification in patients with limited breath‐holding capabilities. For accurate
R2∗ estimation, respiratory‐resolved reconstruction should be used.
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Affiliation(s)
- Manuel Schneider
- Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen Nürnberg, Erlangen, Germany.,MR Applications Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany
| | - Thomas Benkert
- MR Applications Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany
| | - Eddy Solomon
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Dominik Nickel
- MR Applications Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany
| | - Matthias Fenchel
- MR R&D Collaborations, Siemens Medical Solutions, New York, NY, USA
| | - Berthold Kiefer
- MR Applications Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany
| | - Andreas Maier
- Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen Nürnberg, Erlangen, Germany
| | - Hersh Chandarana
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Kai Tobias Block
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, USA
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Hu HH, Branca RT, Hernando D, Karampinos DC, Machann J, McKenzie CA, Wu HH, Yokoo T, Velan SS. Magnetic resonance imaging of obesity and metabolic disorders: Summary from the 2019 ISMRM Workshop. Magn Reson Med 2019; 83:1565-1576. [PMID: 31782551 DOI: 10.1002/mrm.28103] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 11/04/2019] [Accepted: 11/11/2019] [Indexed: 02/06/2023]
Abstract
More than 100 attendees from Australia, Austria, Belgium, Canada, China, Germany, Hong Kong, Indonesia, Japan, Malaysia, the Netherlands, the Philippines, Republic of Korea, Singapore, Sweden, Switzerland, the United Kingdom, and the United States convened in Singapore for the 2019 ISMRM-sponsored workshop on MRI of Obesity and Metabolic Disorders. The scientific program brought together a multidisciplinary group of researchers, trainees, and clinicians and included sessions in diabetes and insulin resistance; an update on recent advances in water-fat MRI acquisition and reconstruction methods; with applications in skeletal muscle, bone marrow, and adipose tissue quantification; a summary of recent findings in brown adipose tissue; new developments in imaging fat in the fetus, placenta, and neonates; the utility of liver elastography in obesity studies; and the emerging role of radiomics in population-based "big data" studies. The workshop featured keynote presentations on nutrition, epidemiology, genetics, and exercise physiology. Forty-four proffered scientific abstracts were also presented, covering the topics of brown adipose tissue, quantitative liver analysis from multiparametric data, disease prevalence and population health, technical and methodological developments in data acquisition and reconstruction, newfound applications of machine learning and neural networks, standardization of proton density fat fraction measurements, and X-nuclei applications. The purpose of this article is to summarize the scientific highlights from the workshop and identify future directions of work.
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Affiliation(s)
- Houchun H Hu
- Department of Radiology, Nationwide Children's Hospital, Columbus, Ohio
| | - Rosa Tamara Branca
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Diego Hernando
- Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin.,Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Dimitrios C Karampinos
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany
| | - Jürgen Machann
- Institute for Diabetes Research and Metabolic Diseases, Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research, Tübingen, Germany.,Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen, Germany
| | - Charles A McKenzie
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - Holden H Wu
- Department of Radiological Sciences, University of California Los Angeles, Los Angeles, California
| | - Takeshi Yokoo
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - S Sendhil Velan
- Singapore Institute for Clinical Sciences, Agency for Science Technology and Research, Singapore.,Singapore BioImaging Consortium, Agency for Science Technology and Research, Singapore
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Sharafi A, Baboli R, Zibetti M, Shanbhogue K, Olsen S, Block T, Chandarana H, Regatte R. Volumetric multicomponent T 1ρ relaxation mapping of the human liver under free breathing at 3T. Magn Reson Med 2019; 83:2042-2050. [PMID: 31724246 DOI: 10.1002/mrm.28061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 10/10/2019] [Accepted: 10/11/2019] [Indexed: 12/16/2022]
Abstract
PURPOSE To develop a 3D sequence for T1ρ relaxation mapping using radial volumetric encoding (3D-T1ρ -RAVE) and to evaluate the multi relaxation components in the liver of healthy controls and chronic liver disease (CLD) patients. METHODS Fat saturation and T1ρ preparation modules were followed by a train of gradient-echo acquisitions and T1 restoration delay. The series of T1ρ -weighted images were fitted using mono-exponential, bi-exponential, and stretched-exponential models. The repeatability and reproducibility of the proposed technique were evaluated on National Institute of Standards and Technology phantom by calculating the coefficient of variation between test-retest scans on the same scanner and between two different 3T scanners, respectively. Mann-Whitney U-test was performed to assess differences in T1ρ components among patients (n = 3) and a control group (n = 10). RESULTS The phantom study showed an error of 8.9% and 11.5% in mono T2 relaxation time measurement relative to the reference on 2 different scanners. The coefficient of variation for test-retest scans performed on the same scanner was 5.7% and 2.4% for scans performed on 2 scanners. The comparison between healthy controls and CLD patients showed a significant difference (P < .05) in mono relaxation time (P = .002), stretched-exponential relaxation parameter (P = .04). The Akaike information criteria C criterion showed 2.53 ± 0.9% (2.3 ± 0.3% for CLD) of the voxels are bi-exponential while in 65.3 ± 5.8% (81.2 ± 0.06% for CLD) of the liver voxels, the stretched-exponential model was preferred. CONCLUSION The 3D-T1ρ -RAVE sequence allows volumetric, multicomponent T1ρ assessment of the liver during free breathing and can distinguish between healthy volunteers and CLD patients.
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Affiliation(s)
- Azadeh Sharafi
- Department of Radiology, New York University School of Medicine, New York, New York
| | - Rahman Baboli
- Department of Radiology, New York University School of Medicine, New York, New York
| | - Marcelo Zibetti
- Department of Radiology, New York University School of Medicine, New York, New York
| | - Krishna Shanbhogue
- Department of Radiology, New York University School of Medicine, New York, New York
| | - Sonja Olsen
- Department of Medicine, New York University School of Medicine, New York, New York
| | - Tobias Block
- Department of Radiology, New York University School of Medicine, New York, New York.,Department of Radiology, University Hospital Basel, Basel, Switzerland
| | - Hersh Chandarana
- Department of Radiology, New York University School of Medicine, New York, New York
| | - Ravinder Regatte
- Department of Radiology, New York University School of Medicine, New York, New York
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Liu S, Wu P, Liu H, Hu Z, Guo H. Referenceless multi‐channel signal combination: A demonstration in chemical‐shift‐encoded water‐fat imaging. Magn Reson Med 2019; 83:1810-1824. [DOI: 10.1002/mrm.28028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 09/09/2019] [Accepted: 09/12/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Simin Liu
- Center for Biomedical Imaging Research Department of Biomedical Engineering School of Medicine Tsinghua University Beijing China
| | - Peng Wu
- Center for Biomedical Imaging Research Department of Biomedical Engineering School of Medicine Tsinghua University Beijing China
- Philips Healthcare Suzhou Co Ltd Suzhou
| | - Haining Liu
- Department of Radiology University of Washington Seattle Washington
| | - Zhangxuan Hu
- Center for Biomedical Imaging Research Department of Biomedical Engineering School of Medicine Tsinghua University Beijing China
| | - Hua Guo
- Center for Biomedical Imaging Research Department of Biomedical Engineering School of Medicine Tsinghua University Beijing China
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Berglund J, Rydén H, Avventi E, Norbeck O, Sprenger T, Skare S. Fat/water separation in k‐space with real‐valued estimates and its combination with POCS. Magn Reson Med 2019; 83:653-661. [DOI: 10.1002/mrm.27949] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 07/09/2019] [Accepted: 07/24/2019] [Indexed: 01/10/2023]
Affiliation(s)
- Johan Berglund
- Department of Clinical Neuroscience Karolinska Institutet Stockholm Sweden
- Department of Neuroradiology Karolinska University Hospital Stockholm Sweden
| | - Henric Rydén
- Department of Clinical Neuroscience Karolinska Institutet Stockholm Sweden
- Department of Neuroradiology Karolinska University Hospital Stockholm Sweden
| | - Enrico Avventi
- Department of Clinical Neuroscience Karolinska Institutet Stockholm Sweden
- Department of Neuroradiology Karolinska University Hospital Stockholm Sweden
| | - Ola Norbeck
- Department of Clinical Neuroscience Karolinska Institutet Stockholm Sweden
- Department of Neuroradiology Karolinska University Hospital Stockholm Sweden
| | - Tim Sprenger
- Department of Clinical Neuroscience Karolinska Institutet Stockholm Sweden
- Applied Science Laboratory Europe GE Healthcare Stockholm Sweden
| | - Stefan Skare
- Department of Clinical Neuroscience Karolinska Institutet Stockholm Sweden
- Department of Neuroradiology Karolinska University Hospital Stockholm Sweden
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Armstrong T, Ly KV, Ghahremani S, Calkins KL, Wu HH. Free-breathing 3-D quantification of infant body composition and hepatic fat using a stack-of-radial magnetic resonance imaging technique. Pediatr Radiol 2019; 49:876-888. [PMID: 31001664 DOI: 10.1007/s00247-019-04384-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 02/12/2019] [Accepted: 03/08/2019] [Indexed: 12/15/2022]
Abstract
BACKGROUND Body composition and hepatic fat correlate with future risk for metabolic syndrome. In children, many conventional techniques for quantifying body composition and hepatic fat have limitations. MRI is a noninvasive research tool to study body composition and hepatic fat in infants; however, conventional Cartesian MRI is sensitive to motion, particularly in the abdomen because of respiration. Therefore we developed a free-breathing MRI technique to quantify body composition and hepatic fat in infants. OBJECTIVE In infants, we aimed to (1) compare the image quality between free-breathing 3-D stack-of-radial MRI (free-breathing radial) and 3-D Cartesian MRI in the liver and (2) determine the feasibility of using free-breathing radial MRI to quantify body composition and hepatic proton-density fat fraction (PDFF). MATERIALS AND METHODS Ten infants ages 2-7 months were scanned with free-breathing radial (two abdominal; one head and chest) and Cartesian (one abdominal) MRI sequences. The median preparation and scan times were reported. To assess feasibility for hepatic PDFF quantification, a radiologist masked to the MRI technique scored abdominal scans for motion artifacts in the liver using a 3-point scale (1, or non-diagnostic, to 3, or no artifacts). Median visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and brown adipose tissue (BAT) volume and PDFF, and hepatic PDFF were measured using free-breathing radial MRI. We assessed repeatability of free-breathing radial hepatic PDFF (coefficient of repeatability) between back-to-back scans. We determined differences in the distribution of image-quality scores using McNemar-Bowker tests. P<0.05 was considered significant. RESULTS Nine infants completed the entire study (90% completion). For ten infants, the median preparation time was 32 min and scan time was 24 min. Free-breathing radial MRI demonstrated significantly higher image-quality scores compared to Cartesian MRI in the liver (radial scan 1 median = 2 and radial scan 2 median = 3 vs. Cartesian median = 1; P=0.01). Median measurements using free-breathing radial were VAT=52.0 cm3, VAT-PDFF=42.2%, SAT=267.7 cm3, SAT-PDFF=87.1%, BAT=1.4 cm3, BAT-PDFF=26.1% and hepatic PDFF=3.4% (coefficient of repeatability <2.0%). CONCLUSION In this study, free-breathing radial MRI in infants achieved significantly improved liver image quality compared to Cartesian MRI. It is feasible to use free-breathing radial MRI to quantify body composition and hepatic fat in infants.
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Affiliation(s)
- Tess Armstrong
- Department of Radiological Sciences, University of California Los Angeles, 300 UCLA Medical Plaza, Ste. B119, Los Angeles, CA, 90095, USA.,Physics and Biology in Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Karrie V Ly
- Department of Pediatrics, Division of Neonatology, David Geffen School of Medicine, University of California Los Angeles, Mattel Children's Hospital, Los Angeles, CA, USA.,Physician Assistant Program, Midwestern University, Glendale, AZ, USA
| | - Shahnaz Ghahremani
- Department of Radiological Sciences, University of California Los Angeles, 300 UCLA Medical Plaza, Ste. B119, Los Angeles, CA, 90095, USA
| | - Kara L Calkins
- Department of Pediatrics, Division of Neonatology, David Geffen School of Medicine, University of California Los Angeles, Mattel Children's Hospital, Los Angeles, CA, USA
| | - Holden H Wu
- Department of Radiological Sciences, University of California Los Angeles, 300 UCLA Medical Plaza, Ste. B119, Los Angeles, CA, 90095, USA. .,Physics and Biology in Medicine, University of California Los Angeles, Los Angeles, CA, USA.
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35
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Hu HH, Benkert T, Jones JY, McAllister AS, Rusin JA, Krishnamurthy R, Block KT. 3D T1-weighted contrast-enhanced brain MRI in children using a fat-suppressed golden angle radial acquisition: an alternative to Cartesian inversion-recovery imaging. Clin Imaging 2019; 55:112-118. [DOI: 10.1016/j.clinimag.2019.02.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 09/18/2018] [Accepted: 02/08/2019] [Indexed: 02/07/2023]
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Tan Z, Voit D, Kollmeier JM, Uecker M, Frahm J. Dynamic water/fat separation and B 0 inhomogeneity mapping-joint estimation using undersampled triple-echo multi-spoke radial FLASH. Magn Reson Med 2019; 82:1000-1011. [PMID: 31033051 DOI: 10.1002/mrm.27795] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/26/2019] [Accepted: 04/10/2019] [Indexed: 11/05/2022]
Abstract
PURPOSE To achieve dynamic water/fat separation and B 0 field inhomogeneity mapping via model-based reconstructions of undersampled triple-echo multi-spoke radial FLASH acquisitions. METHODS This work introduces an undersampled triple-echo multi-spoke radial FLASH sequence, which uses (i) complementary radial spokes per echo train for faster spatial encoding, (ii) asymmetric echoes for flexible and nonuniform echo spacing, and (iii) a golden angle increment across frames for optimal k-space coverage. Joint estimation of water, fat, B 0 inhomogeneity, and coil sensitivity maps from undersampled triple-echo data poses a nonlinear and non-convex inverse problem which is solved by a model-based reconstruction with suitable regularization. The developed methods are validated using phantom experiments with different degrees of undersampling. Real-time MRI studies of the knee, liver, and heart are conducted without prospective gating or retrospective data sorting at temporal resolutions of 70, 158, and 40 ms, respectively. RESULTS Up to 18-fold undersampling is achieved in this work. Even in the presence of rapid physiological motion, large B 0 field inhomogeneities, and phase wrapping, the model-based reconstruction yields reliably separated water/fat maps in conjunction with spatially smooth inhomogeneity maps. CONCLUSIONS The combination of a triple-echo acquisition and joint reconstruction technique provides a practical solution to time-resolved and motion robust water/fat separation at high spatial and temporal resolution.
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Affiliation(s)
- Zhengguo Tan
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.,Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Göttingen, Germany
| | - Dirk Voit
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Jost M Kollmeier
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Martin Uecker
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR, Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), partner site Göttingen, Göttingen, Germany
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Cao J, Pickup S, Clendenin C, Blouw B, Choi H, Kang D, Rosen M, O'Dwyer PJ, Zhou R. Dynamic Contrast-enhanced MRI Detects Responses to Stroma-directed Therapy in Mouse Models of Pancreatic Ductal Adenocarcinoma. Clin Cancer Res 2019; 25:2314-2322. [PMID: 30587546 PMCID: PMC6445712 DOI: 10.1158/1078-0432.ccr-18-2276] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 11/20/2018] [Accepted: 12/19/2018] [Indexed: 12/18/2022]
Abstract
PURPOSE The dense stroma underlies the drug resistance of pancreatic ductal adenocarcinoma (PDA) and has motivated the development of stroma-directed drugs. Our objective is to test the concept that dynamic contrast-enhanced (DCE) MRI using FDA-approved contrast media, an imaging method sensitive to the tumor microenvironment, can detect early responses to stroma-directed drug. EXPERIMENTAL DESIGN Imaging studies were performed in three mouse models exhibiting high desmoplastic reactions: the autochthonous PDA in genetically engineered mice (KPC), an orthotopic model in syngeneic mice, and a xenograft model of human PDA in athymic mice. An investigational drug, PEGPH20 (pegvorhyaluronidase alfa), which degrades hyaluronan (HA) in the stroma of PDA, was injected alone or in combination with gemcitabine. RESULTS At 24 hours after a single injection of PEGPH20, Ktrans , a DCE-MRI-derived marker that measures how fast a unit volume of contrast media is transferred from capillaries to interstitial space, increased 56% and 50% from baseline in the orthotopic and xenograft tumors, respectively, compared with a 4% and 6% decrease in vehicle groups (both P < 0.05). Similarly, after three combined treatments, Ktrans in KPC mice increased 54%, whereas it decreased 4% in controls treated with gemcitabine alone (P < 0.05). Consistently, after a single injection of PEGPH20, tumor HA content assessed by IHC was reduced substantially in all three models while drug delivery (measured by paclitaxel accumulation in tumor) was increased by 2.6-fold. CONCLUSIONS These data demonstrated a DCE-MRI marker, Ktrans , can detect early responses to stroma-directed drug and reveal the sustained effect of combination treatment (PEGPH20+ gemcitabine).
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Affiliation(s)
- Jianbo Cao
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
- Medical College, Xiamen University, Xiamen, Fujian, P.R. China
| | - Stephen Pickup
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cynthia Clendenin
- Pancreatic Cancer Research Center, University of Pennsylvania, Philadelphia, Pennsylvania
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Hoon Choi
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - David Kang
- Halozyme Therapeutics, San Diego, California
| | - Mark Rosen
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Peter J O'Dwyer
- Pancreatic Cancer Research Center, University of Pennsylvania, Philadelphia, Pennsylvania.
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rong Zhou
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, Pennsylvania
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Dong SZ, Zhu M, Bulas D. Techniques for minimizing sedation in pediatric MRI. J Magn Reson Imaging 2019; 50:1047-1054. [PMID: 30869831 DOI: 10.1002/jmri.26703] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 02/17/2019] [Accepted: 02/19/2019] [Indexed: 12/16/2022] Open
Abstract
MRI is used widely in infants and young children. However, in these young cases deep sedation or general anesthesia is often required to minimize motion artifacts during MRI examinations. Although the benefits of MR typically outweigh the potential risks of sedation when delivered by an experienced team, there are increasing concerns regarding the affect of sedation on young children. There continues to be a push to develop various strategies that can minimize the need for sedation. The present review summarizes several technical and clinical approaches that can help decrease the need for sedation in the pediatric patient. Optimization of the MRI environment, the role of child life specialists, feed-and-bundle and distraction techniques, noise-reduction methods, artificial intelligence, and MRI advances to decrease both scan times and motion artifacts will be discussed. Level of Evidence: 5 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019.
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Affiliation(s)
- Su-Zhen Dong
- Department of Radiology, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China.,Department of Diagnostic Imaging and Radiology, Children's National Health Systems, Washington, DC, USA
| | - Ming Zhu
- Department of Radiology, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Dorothy Bulas
- Department of Diagnostic Imaging and Radiology, Children's National Health Systems, Washington, DC, USA
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Shi X, Levine E, Weber H, Hargreaves BA. Accelerated imaging of metallic implants using model-based nonlinear reconstruction. Magn Reson Med 2018; 81:2247-2263. [PMID: 30515853 DOI: 10.1002/mrm.27536] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 08/23/2018] [Accepted: 08/24/2018] [Indexed: 12/26/2022]
Abstract
PURPOSE To accelerate imaging near metallic implants with multi-spectral imaging (MSI) techniques by exploiting a signal model in the spectral dimension. METHODS MSI techniques resolve metal-induced field perturbations by acquiring separate 3D spatial encodings at multiple excitation frequencies, which are referred to as spectral bins. The proposed model-based reconstruction exploits the correlation between spectral bins in image reconstruction by enforcing a signal model to describe the signal profile across bins. This work evaluates the accuracy of the MSI signal model in simulations and in vivo experiments. The proposed model-based reconstruction was evaluated in 6 subjects at an overall undersampling factor of 17.4 and compared with model-free parallel imaging and compressed sensing (PI & CS). The quality of reconstructed images was evaluated using normalized RMS error (nRMSE) and structural similarity index (SSIM) comparisons, with paired Wilcoxon tests in 6 subjects used to determine whether there was a significant difference in the metrics. RESULTS Both simulations and in vivo experiments show that the proposed signal model can represent the MSI signal profiles in the spectral dimension compactly and accurately. In the in vivo experiments, the model-based reconstruction significantly improved image quality over model-free PI & CS, with P < 0.05 for both nRMSE and SSIM at 17.4× acceleration. CONCLUSION This work presents the feasibility of using a model-based reconstruction to accelerate MSI techniques for faster MR imaging near metal.
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Affiliation(s)
- Xinwei Shi
- Department of Radiology, Stanford University, Stanford, California.,Department of Electrical Engineering, Stanford University, Stanford, California
| | - Evan Levine
- Department of Radiology, Stanford University, Stanford, California.,Department of Electrical Engineering, Stanford University, Stanford, California
| | - Hans Weber
- Department of Radiology, Stanford University, Stanford, California
| | - Brian A Hargreaves
- Department of Radiology, Stanford University, Stanford, California.,Department of Electrical Engineering, Stanford University, Stanford, California.,Department of Bioengineering, Stanford University, Stanford, California
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Johansson A, Balter JM, Cao Y. Abdominal DCE-MRI reconstruction with deformable motion correction for liver perfusion quantification. Med Phys 2018; 45:4529-4540. [PMID: 30098044 DOI: 10.1002/mp.13118] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 07/29/2018] [Accepted: 07/29/2018] [Indexed: 01/01/2023] Open
Abstract
PURPOSE Abdominal dynamic contrast-enhanced (DCE) MRI suffers from motion-induced artifacts that can blur images and distort contrast-agent uptake curves. For liver perfusion analysis, image reconstruction with rigid-body motion correction (RMC) can restore distorted portal-venous input functions (PVIF) to higher peak amplitudes. However, RMC cannot correct for liver deformation during breathing. We present a reconstruction algorithm with deformable motion correction (DMC) that enables correction of breathing-induced deformation in the whole abdomen. METHODS Raw data from a golden-angle stack-of-stars gradient-echo sequence were collected for 54 DCE-MRI examinations of 31 patients. For each examination, a respiratory motion signal was extracted from the data and used to reconstruct 21 breathing states from inhale to exhale. The states were aligned with deformable image registration to the end-exhale state. Resulting deformation fields were used to correct back-projection images before reconstruction with view sharing. Images with DMC were compared to uncorrected images and images with RMC. RESULTS DMC significantly increased the PVIF peak amplitude compared to uncorrected images (P << 0.01, mean increase: 8%) but not compared to RMC. The increased PVIF peak amplitude significantly decreased estimated portal-venous perfusion in the liver (P << 0.01, mean decrease: 8 ml/(100 ml·min)). DMC also removed artifacts in perfusion maps at the liver edge and reduced blurring of liver tumors for some patients. CONCLUSIONS DCE-MRI reconstruction with DMC can restore motion-distorted uptake curves in the abdomen and remove motion artifacts from reconstructed images and parameter maps but does not significantly improve perfusion quantification in the liver compared to RMC.
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Affiliation(s)
- Adam Johansson
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - James M Balter
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Yue Cao
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Radiology, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
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Fast, free-breathing and motion-minimized techniques for pediatric body magnetic resonance imaging. Pediatr Radiol 2018; 48:1197-1208. [PMID: 30078042 DOI: 10.1007/s00247-018-4116-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/26/2018] [Accepted: 03/11/2018] [Indexed: 12/26/2022]
Abstract
Magnetic resonance imaging (MRI) is the preferred imaging modality in children with complex medical issues. Patient motion and respiration remain major challenges in pediatric abdominal MRI. Young children ages 3 months to 6 years are unable to cooperate or perform breath-holding and frequently require deep sedation or general anesthesia to undergo MRI. Given the growing concerns associated with the use of sedation and anesthesia as well as the adverse impact on workflow, developing and implementing fast and motion-resistant MRI sequences are of great interest. Fast sequences such as single-shot fast spin echo and balanced steady-state free precession are useful as quick anatomical surveys on routine abdominal MRI. The widespread utilization of parallel imaging and sequences with radial k-space sampling has contributed to decreasing scan time and improving image quality, respectively. Newer strategies including compressed sensing, simultaneous multi-slice acquisition, and hybrid approaches hold the prospect of faster image acquisition that could significantly reduce the need for sedation in this vulnerable population and decrease the time of anesthesia in cases where it is indicated.
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Comprehensive Dynamic Contrast-Enhanced 3D Magnetic Resonance Imaging of the Breast With Fat/Water Separation and High Spatiotemporal Resolution Using Radial Sampling, Compressed Sensing, and Parallel Imaging. Invest Radiol 2018; 52:583-589. [PMID: 28398929 DOI: 10.1097/rli.0000000000000375] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The aim of this study was to assess the applicability of Dixon radial volumetric encoding (Dixon-RAVE) for comprehensive dynamic contrast-enhanced 3D magnetic resonance imaging (MRI) of the breast using a combination of radial sampling, model-based fat/water separation, compressed sensing, and parallel imaging. MATERIALS AND METHODS In this Health Insurance Portability and Accountability Act-compliant prospective study, 24 consecutive patients underwent bilateral breast MRI, including both conventional fat-suppressed and non-fat-suppressed precontrast T1-weighted volumetric interpolated breath-hold examination (VIBE). Afterward, 1 continuous Dixon-RAVE scan was performed with the proposed approach while the contrast agent was injected. This scan was immediately followed by the acquisition of 4 conventional fat-saturated VIBE scans. From the comprehensive Dixon-RAVE data set, different image contrasts were reconstructed that are comparable to the separate conventional VIBE scans.Two radiologists independently rated image quality, conspicuity of fibroglandular tissue from fat (FG), and degree of fat suppression (FS) on a 5-point Likert-type scale for the following 3 comparisons: precontrast fat-suppressed (pre-FS), precontrast non-fat-suppressed (pre-NFS), and dynamic fat-suppressed (dyn-FS) images. RESULTS When scores were averaged over readers, Dixon-RAVE achieved significantly higher (P < 0.001) degree of fat suppression compared with VIBE, for both pre-FS (4.25 vs 3.67) and dyn-FS (4.10 vs 3.46) images. Although Dixon-RAVE had lower image quality score compared with VIBE for the pre-FS (3.56 vs 3.67, P = 0.490), the pre-NFS (3.54 vs 3.88, P = 0.009), and the dyn-FS images (3.06 vs 3.67, P < 0.001), acceptable or better diagnostic quality was achieved (score ≥ 3). The FG score for Dixon-RAVE in comparison to VIBE was significantly higher for the pre-FS image (4.23 vs 3.85, P = 0.044), lower for the pre-NFS image (3.98 vs 4.25, P = 0.054), and higher for the dynamic fat-suppressed image (3.90 vs 3.85, P = 0.845). CONCLUSIONS Dixon-RAVE can serve as a one-stop-shop approach for comprehensive T1-weighted breast MRI with diagnostic image quality, high spatiotemporal resolution, reduced overall scan time, and improved fat suppression compared with conventional imaging.
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Benkert T, Mugler JP, Rigie DS, Sodickson DK, Chandarana H, Block KT. Hybrid T 2 - and T 1 -weighted radial acquisition for free-breathing abdominal examination. Magn Reson Med 2018; 80:1935-1948. [PMID: 29656522 DOI: 10.1002/mrm.27200] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 02/14/2018] [Accepted: 03/09/2018] [Indexed: 12/13/2022]
Abstract
PURPOSE Most clinical MR examinations require acquisition of different image contrasts. For abdominal exams, the scans are conventionally performed as separate acquisitions using respiratory gating or repeated breath holding, which can be time-inefficient and challenging for patients. Here, a hybrid imaging approach is described that creates T2 - and T1 -weighted images from a single scan and allows for free-breathing acquisition. THEORY AND METHODS T2 -weighted data is collected using 3D fast spin-echo (FSE) acquisition with motion-robust radial stack-of-stars sampling. The wait time between the FSE trains is used to acquire T1 -weighted gradient-echo (GRE) data. Improved robustness is achieved by extracting a respiratory signal from the GRE data and using it for motion-weighted reconstruction. RESULTS As validated in simulations and phantom scans, GRE acquisition in the wait time has minor effect on the signal strength and contrast. Volunteer scans at 1.5T showed that T2 - and T1 -weighted hybrid imaging is feasible during free-breathing. Furthermore, it has been demonstrated in a patient that hybrid imaging with T1 -weighted Dixon acquisition is possible. CONCLUSION The described hybrid sequence enables comprehensive T2 - and T1 -weighted imaging in a single scan. In addition to free-breathing abdominal examination, it promises value for clinical applications that are frequently affected by motion artifacts.
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Affiliation(s)
- Thomas Benkert
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York.,Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York
| | - John P Mugler
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia
| | - David S Rigie
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York.,Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York
| | - Daniel K Sodickson
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York.,Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York
| | - Hersh Chandarana
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York.,Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York
| | - Kai Tobias Block
- Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York.,Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York
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44
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Jimenez JE, Strigel RM, Johnson KM, Henze Bancroft LC, Reeder SB, Block WF. Feasibility of high spatiotemporal resolution for an abbreviated 3D radial breast MRI protocol. Magn Reson Med 2018; 80:1452-1466. [PMID: 29446125 DOI: 10.1002/mrm.27137] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 01/24/2018] [Accepted: 01/25/2018] [Indexed: 12/11/2022]
Abstract
PURPOSE To develop a volumetric imaging technique with 0.8-mm isotropic resolution and 10-s/volume rate to detect and analyze breast lesions in a bilateral, dynamic, contrast-enhanced MRI exam. METHODS A local low-rank temporal reconstruction approach that also uses parallel imaging and spatial compressed sensing was designed to create rapid volumetric frame rates during a contrast-enhanced breast exam (vastly undersampled isotropic projection [VIPR] spatial compressed sensing with temporal local low-rank [STELLR]). The dynamic-enhanced data are subtracted in k-space from static mask data to increase sparsity for the local low-rank approach to maximize temporal resolution. A T1 -weighted 3D radial trajectory (VIPR iterative decomposition with echo asymmetry and least squares estimation [IDEAL]) was modified to meet the data acquisition requirements of the STELLR approach. Additionally, the unsubtracted enhanced data are reconstructed using compressed sensing and IDEAL to provide high-resolution fat/water separation. The feasibility of the approach and the dual reconstruction methodology is demonstrated using a 16-channel breast coil and a 3T MR scanner in 6 patients. RESULTS The STELLR temporal performance of subtracted data matched the expected temporal perfusion enhancement pattern in small and large vascular structures. Differential enhancement within heterogeneous lesions is demonstrated with corroboration from a basic reconstruction using a strict 10-second temporal footprint. Rapid acquisition, reliable fat suppression, and high spatiotemporal resolution are presented, despite significant data undersampling. CONCLUSION The STELLR reconstruction approach of 3D radial sampling with mask subtraction provides a high-performance imaging technique for characterizing enhancing structures within the breast. It is capable of maintaining temporal fidelity, while visualizing breast lesions with high detail over a large FOV to include both breasts.
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Affiliation(s)
- Jorge E Jimenez
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin
| | - Roberta M Strigel
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin.,Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.,Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin
| | - Kevin M Johnson
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin
| | - Leah C Henze Bancroft
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Scott B Reeder
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin.,Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.,Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin.,Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.,Department of Emergency Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Walter F Block
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin.,Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.,Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin
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45
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Giza SA, Miller MR, Parthasarathy P, de Vrijer B, McKenzie CA. Comparison of modified two-point dixon and chemical shift encoded MRI water-fat separation methods for fetal fat quantification. J Magn Reson Imaging 2018; 48:274-282. [DOI: 10.1002/jmri.25929] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/05/2017] [Indexed: 12/15/2022] Open
Affiliation(s)
- Stephanie A. Giza
- Department of Medical Biophysics; Western University; London Ontario Canada
| | - Michael R. Miller
- Division of Maternal, Fetal and Newborn Health; Children's Health Research Institute; London Ontario Canada
- Department of Paediatrics; Western University; London Ontario Canada
| | | | - Barbra de Vrijer
- Division of Maternal, Fetal and Newborn Health; Children's Health Research Institute; London Ontario Canada
- Department of Obstetrics and Gynaecology; Western University; London Ontario Canada
| | - Charles A. McKenzie
- Department of Medical Biophysics; Western University; London Ontario Canada
- Division of Maternal, Fetal and Newborn Health; Children's Health Research Institute; London Ontario Canada
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46
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Benkert T, Tian Y, Huang C, DiBella EVR, Chandarana H, Feng L. Optimization and validation of accelerated golden-angle radial sparse MRI reconstruction with self-calibrating GRAPPA operator gridding. Magn Reson Med 2017; 80:286-293. [PMID: 29193380 DOI: 10.1002/mrm.27030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/02/2017] [Accepted: 11/10/2017] [Indexed: 12/24/2022]
Abstract
PURPOSE Golden-angle radial sparse parallel (GRASP) MRI reconstruction requires gridding and regridding to transform data between radial and Cartesian k-space. These operations are repeatedly performed in each iteration, which makes the reconstruction computationally demanding. This work aimed to accelerate GRASP reconstruction using self-calibrating GRAPPA operator gridding (GROG) and to validate its performance in clinical imaging. METHODS GROG is an alternative gridding approach based on parallel imaging, in which k-space data acquired on a non-Cartesian grid are shifted onto a Cartesian k-space grid using information from multicoil arrays. For iterative non-Cartesian image reconstruction, GROG is performed only once as a preprocessing step. Therefore, the subsequent iterative reconstruction can be performed directly in Cartesian space, which significantly reduces computational burden. Here, a framework combining GROG with GRASP (GROG-GRASP) is first optimized and then compared with standard GRASP reconstruction in 22 prostate patients. RESULTS GROG-GRASP achieved approximately 4.2-fold reduction in reconstruction time compared with GRASP (∼333 min versus ∼78 min) while maintaining image quality (structural similarity index ≈ 0.97 and root mean square error ≈ 0.007). Visual image quality assessment by two experienced radiologists did not show significant differences between the two reconstruction schemes. With a graphics processing unit implementation, image reconstruction time can be further reduced to approximately 14 min. CONCLUSION The GRASP reconstruction can be substantially accelerated using GROG. This framework is promising toward broader clinical application of GRASP and other iterative non-Cartesian reconstruction methods. Magn Reson Med 80:286-293, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Thomas Benkert
- Center for Advanced Imaging Innovation and Research (CAI2R), and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Ye Tian
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA.,Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah, USA
| | - Chenchan Huang
- Center for Advanced Imaging Innovation and Research (CAI2R), and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Edward V R DiBella
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Hersh Chandarana
- Center for Advanced Imaging Innovation and Research (CAI2R), and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Li Feng
- Center for Advanced Imaging Innovation and Research (CAI2R), and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
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47
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Stemkens B, Benkert T, Chandarana H, Bittman ME, Van den Berg CA, Lagendijk JJ, Sodickson DK, Tijssen RH, Block KT. Adaptive bulk motion exclusion for improved robustness of abdominal magnetic resonance imaging. NMR IN BIOMEDICINE 2017; 30:e3830. [PMID: 28885742 PMCID: PMC5643254 DOI: 10.1002/nbm.3830] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/03/2017] [Accepted: 08/14/2017] [Indexed: 05/09/2023]
Abstract
Non-Cartesian magnetic resonance imaging (MRI) sequences have shown great promise for abdominal examination during free breathing, but break down in the presence of bulk patient motion (i.e. voluntary or involuntary patient movement resulting in translation, rotation or elastic deformations of the body). This work describes a data-consistency-driven image stabilization technique that detects and excludes bulk movements during data acquisition. Bulk motion is identified from changes in the signal intensity distribution across different elements of a multi-channel receive coil array. A short free induction decay signal is acquired after excitation and used as a measure to determine alterations in the load distribution. The technique has been implemented on a clinical MR scanner and evaluated in the abdomen. Six volunteers were scanned and two radiologists scored the reconstructions. To show the applicability to other body areas, additional neck and knee images were acquired. Data corrupted by bulk motion were successfully detected and excluded from image reconstruction. An overall increase in image sharpness and reduction of streaking and shine-through artifacts were seen in the volunteer study, as well as in the neck and knee scans. The proposed technique enables automatic real-time detection and exclusion of bulk motion during MR examinations without user interaction. It may help to improve the reliability of pediatric MRI examinations without the use of sedation.
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Affiliation(s)
- Bjorn Stemkens
- Department of RadiotherapyUniversity Medical Center Utrechtthe Netherlands
| | - Thomas Benkert
- Center for Advanced Imaging Innovation and Research (CAIR), Department of RadiologyNew York University School of MedicineNew YorkNYUSA
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of RadiologyNew York University School of MedicineNew YorkNYUSA
| | - Hersh Chandarana
- Center for Advanced Imaging Innovation and Research (CAIR), Department of RadiologyNew York University School of MedicineNew YorkNYUSA
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of RadiologyNew York University School of MedicineNew YorkNYUSA
| | - Mark E. Bittman
- Center for Advanced Imaging Innovation and Research (CAIR), Department of RadiologyNew York University School of MedicineNew YorkNYUSA
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of RadiologyNew York University School of MedicineNew YorkNYUSA
| | | | - Jan J.W. Lagendijk
- Department of RadiotherapyUniversity Medical Center Utrechtthe Netherlands
| | - Daniel K. Sodickson
- Center for Advanced Imaging Innovation and Research (CAIR), Department of RadiologyNew York University School of MedicineNew YorkNYUSA
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of RadiologyNew York University School of MedicineNew YorkNYUSA
| | - Rob H.N. Tijssen
- Department of RadiotherapyUniversity Medical Center Utrechtthe Netherlands
| | - Kai Tobias Block
- Center for Advanced Imaging Innovation and Research (CAIR), Department of RadiologyNew York University School of MedicineNew YorkNYUSA
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of RadiologyNew York University School of MedicineNew YorkNYUSA
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48
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Svedin BT, Payne A, Bolster BD, Parker DL. Multiecho pseudo-golden angle stack of stars thermometry with high spatial and temporal resolution using k-space weighted image contrast. Magn Reson Med 2017. [PMID: 28643383 DOI: 10.1002/mrm.26797] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE Implement and evaluate a 3D MRI method to measure temperature changes with high spatial and temporal resolution and large field of view. METHODS A multiecho pseudo-golden angle stack-of-stars (SOS) sequence with k-space weighted image contrast (KWIC) reconstruction was implemented to simultaneously measure multiple quantities, including temperature, initial signal magnitude M(0), transverse relaxation time ( T2*), and water/fat images. Respiration artifacts were corrected using self-navigation. KWIC artifacts were removed using a multi-baseline library. The phases of the multiple echo images were combined to improve proton resonance frequency precision. Temperature precision was tested through in vivo breast imaging (N = 5 healthy volunteers) using both coronal and sagittal orientations and with focused ultrasound (FUS) heating in a pork phantom using a breast specific MR-guided FUS system. RESULTS Temperature measurement precision was significantly improved after echo combination when compared with the no echo combination case (spatial average of the standard deviation through time of 0.3-1.0 and 0.7-1.9°C, respectively). Temperature measurement accuracy during heating was comparable to a 3D seg-EPI sequence. M(0) and T2* values showed temperature dependence during heating in pork adipose tissue. CONCLUSION A self-navigated 3D multiecho SOS sequence with dynamic KWIC reconstruction is a promising thermometry method that provides multiple temperature sensitive quantitative values. Magn Reson Med 79:1407-1419, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Bryant T Svedin
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Allison Payne
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | | | - Dennis L Parker
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
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49
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Johansson A, Balter J, Cao Y. Rigid-body motion correction of the liver in image reconstruction for golden-angle stack-of-stars DCE MRI. Magn Reson Med 2017; 79:1345-1353. [PMID: 28617993 DOI: 10.1002/mrm.26782] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 12/25/2022]
Abstract
PURPOSE Respiratory motion can affect pharmacokinetic perfusion parameters quantified from liver dynamic contrast-enhanced MRI. Image registration can be used to align dynamic images after reconstruction. However, intra-image motion blur remains after alignment and can alter the shape of contrast-agent uptake curves. We introduce a method to correct for inter- and intra-image motion during image reconstruction. METHODS Sixteen liver dynamic contrast-enhanced MRI examinations of nine subjects were performed using a golden-angle stack-of-stars sequence. For each examination, an image time series with high temporal resolution but severe streak artifacts was reconstructed. Images were aligned using region-limited rigid image registration within a region of interest covering the liver. The transformations resulting from alignment were used to correct raw data for motion by modulating and rotating acquired lines in k-space. The corrected data were then reconstructed using view sharing. RESULTS Portal-venous input functions extracted from motion-corrected images had significantly greater peak signal enhancements (mean increase: 16%, t-test, P < 0.001) than those from images aligned using image registration after reconstruction. In addition, portal-venous perfusion maps estimated from motion-corrected images showed fewer artifacts close to the edge of the liver. CONCLUSIONS Motion-corrected image reconstruction restores uptake curves distorted by motion. Motion correction also reduces motion artifacts in estimated perfusion parameter maps. Magn Reson Med 79:1345-1353, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Adam Johansson
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA
| | - James Balter
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Yue Cao
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA.,Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
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50
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Feng L, Benkert T, Block KT, Sodickson DK, Otazo R, Chandarana H. Compressed sensing for body MRI. J Magn Reson Imaging 2016; 45:966-987. [PMID: 27981664 DOI: 10.1002/jmri.25547] [Citation(s) in RCA: 190] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/25/2016] [Indexed: 12/18/2022] Open
Abstract
The introduction of compressed sensing for increasing imaging speed in magnetic resonance imaging (MRI) has raised significant interest among researchers and clinicians, and has initiated a large body of research across multiple clinical applications over the last decade. Compressed sensing aims to reconstruct unaliased images from fewer measurements than are traditionally required in MRI by exploiting image compressibility or sparsity. Moreover, appropriate combinations of compressed sensing with previously introduced fast imaging approaches, such as parallel imaging, have demonstrated further improved performance. The advent of compressed sensing marks the prelude to a new era of rapid MRI, where the focus of data acquisition has changed from sampling based on the nominal number of voxels and/or frames to sampling based on the desired information content. This article presents a brief overview of the application of compressed sensing techniques in body MRI, where imaging speed is crucial due to the presence of respiratory motion along with stringent constraints on spatial and temporal resolution. The first section provides an overview of the basic compressed sensing methodology, including the notion of sparsity, incoherence, and nonlinear reconstruction. The second section reviews state-of-the-art compressed sensing techniques that have been demonstrated for various clinical body MRI applications. In the final section, the article discusses current challenges and future opportunities. LEVEL OF EVIDENCE 5 J. Magn. Reson. Imaging 2017;45:966-987.
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Affiliation(s)
- Li Feng
- Center for Advanced Imaging Innovation and Research (CAI2R), and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Thomas Benkert
- Center for Advanced Imaging Innovation and Research (CAI2R), and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Kai Tobias Block
- Center for Advanced Imaging Innovation and Research (CAI2R), and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Daniel K Sodickson
- Center for Advanced Imaging Innovation and Research (CAI2R), and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Ricardo Otazo
- Center for Advanced Imaging Innovation and Research (CAI2R), and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Hersh Chandarana
- Center for Advanced Imaging Innovation and Research (CAI2R), and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
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