1
|
Malmberg MA, Odéen H, Hofstetter LW, Hadley JR, Parker DL. Validation of single reference variable flip angle (SR-VFA) dynamic T 1 mapping with T 2 * correction using a novel rotating phantom. Magn Reson Med 2024; 91:1419-1433. [PMID: 38115639 PMCID: PMC10872756 DOI: 10.1002/mrm.29944] [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: 06/27/2023] [Revised: 10/12/2023] [Accepted: 11/09/2023] [Indexed: 12/21/2023]
Abstract
PURPOSE To validate single reference variable flip angle (SR-VFA) dynamic T1 mapping with and without T2 * correction against inversion recovery (IR) T1 measurements. METHODS A custom cylindrical phantom with three concentric compartments was filled with variably doped agar to produce a smooth spatial gradient of the T1 relaxation rate as a function of angle across each compartment. IR T1 , VFA T1 , and B1 + measurements were made on the phantom before rotation, and multi-echo stack-of-radial dynamic images were acquired during rotation via an MRI-compatible motor. B1 + -corrected SR-VFA and SR-VFA-T2 * T1 maps were computed from the sliding window reconstructed images and compared against rotationally registered IR and VFA T1 maps to determine the percentage error. RESULTS Both VFA and SR-VFA-T2 * T1 maps fell within 10% of IR T1 measurements for a low rotational speed, with a mean accuracy of 2.3% ± 2.6% and 2.8% ± 2.6%, respectively. Increasing rotational speed was found to decrease the accuracy due to increasing temporal smoothing over ranges where the T1 change had a nonconstant slope. SR-VFA T1 mapping was found to have similar accuracy as the SR-VFA-T2 * and VFA methods at low TEs (˜<2 ms), whereas accuracy degraded strongly with later TEs. T2 * correction of the SR-VFA T1 maps was found to consistently improve accuracy and precision, especially at later TEs. CONCLUSION SR-VFA-T2 * dynamic T1 mapping was found to be accurate against reference IR T1 measurements within 10% in an agar phantom. Further validation is needed in mixed fat-water phantoms and in vivo.
Collapse
Affiliation(s)
- Michael A. Malmberg
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA
| | - Henrik Odéen
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA
| | | | - J. Rock Hadley
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA
| | - Dennis L. Parker
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA
| |
Collapse
|
2
|
Xu P, Meersmann T, Wang J, Wang C. Review of oxygen-enhanced lung mri: Pulse sequences for image acquisition and T 1 measurement. Med Phys 2023; 50:5987-6007. [PMID: 37345214 DOI: 10.1002/mp.16553] [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: 08/17/2021] [Revised: 03/23/2023] [Accepted: 05/16/2023] [Indexed: 06/23/2023] Open
Abstract
Oxygen-enhanced MR imaging (OE-MRI) is a special proton imaging technique that can be performed without modifying the scanner hardware. Many fundamental studies have been conducted following the initial reporting of this technique in 1996, illustrating the high potential for its clinical application. This review aims to summarise and analyse current pulse sequences and T1 measurement methods for OE-MRI, including fundamental theories, existing pulse sequences applied to OE-MRI acquisition and T1 mapping. Wash-in and wash-out time identify lung function and are sensitive to ventilation; thus, dynamic OE-MRI is also discussed in this review. We compare OE-MRI with the primary competitive technique, hyperpolarised gas MRI. Finally, an overview of lower-field applications of OE-MRI is highlighted, as relatively recent publications demonstrated positive results. Lower-field OE-MRI, which is lower than 1.5 T, could be an alternative modality for detecting lung diseases. This educational review is aimed at researchers who want a quick summary of the steps needed to perform pulmonary OE-MRI with a particular focus on sequence design, settings, and quantification methods.
Collapse
Affiliation(s)
- Pengfei Xu
- Department of Electrical and Electronic Engineering, Faculty of Science and Engineering, University of Nottingham Ningbo China, Ningbo, China
| | - Thomas Meersmann
- Sir Peter Mansfield Magnetic Imaging Centre, University of Nottingham, Nottingham, UK
- Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute, Ningbo, China
| | - Jing Wang
- Department of Electrical and Electronic Engineering, Faculty of Science and Engineering, University of Nottingham Ningbo China, Ningbo, China
- Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute, Ningbo, China
| | - Chengbo Wang
- Department of Electrical and Electronic Engineering, Faculty of Science and Engineering, University of Nottingham Ningbo China, Ningbo, China
- Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute, Ningbo, China
| |
Collapse
|
3
|
Belsley G, Tyler DJ, Robson MD, Tunnicliffe EM. Optimal flip angles for in vivo liver 3D T 1 mapping and B 1+ mapping at 3T. Magn Reson Med 2023; 90:950-962. [PMID: 37125661 PMCID: PMC10952198 DOI: 10.1002/mrm.29683] [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: 11/27/2022] [Revised: 04/01/2023] [Accepted: 04/10/2023] [Indexed: 05/02/2023]
Abstract
PURPOSE The spoiled gradient recalled echo (SPGR) sequence with variable flip angles (FAs) enables whole liverT 1 $$ {T}_1 $$ mapping at high spatial resolutions but is strongly affected byB 1 + $$ {B}_1^{+} $$ inhomogeneities. The aim of this work was to study how the precision of acquiredT 1 $$ {T}_1 $$ maps is affected by theT 1 $$ {T}_1 $$ andB 1 + $$ {B}_1^{+} $$ ranges observed in the liver at 3T, as well as how noise propagates from the acquired signals into the resultingT 1 $$ {T}_1 $$ map. THEORY TheT 1 $$ {T}_1 $$ variance was estimated through the Fisher information matrix with a total noise variance including, for the first time, theB 1 + $$ {B}_1^{+} $$ map noise as well as contributions from the SPGR noise. METHODS Simulations were used to find the optimal FAs for both theB 1 + $$ {B}_1^{+} $$ mapping andT 1 $$ {T}_1 $$ mapping. The simulations results were validated in 10 volunteers. RESULTS Four optimized SPGR FAs of 2°, 2°, 15°, and 15° (TR = 4.1 ms) andB 1 + $$ {B}_1^{+} $$ map FAs of 65° and 130° achieved aT 1 $$ {T}_1 $$ coefficient of variation of 6.2 ± 1.7% across 10 volunteers and validated our theoretical model. Four optimal FAs outperformed five uniformly spaced FAs, saving the patient one breath-hold. For the liverB 1 + $$ {B}_1^{+} $$ andT 1 $$ {T}_1 $$ parameter space at 3T, a higher return inT 1 $$ {T}_1 $$ precision was obtained by investing FAs in the SPGR acquisition rather than in theB 1 + $$ {B}_1^{+} $$ map. CONCLUSION A novel framework was developed and validated to calculate the SPGRT 1 $$ {T}_1 $$ variance. This framework efficiently identifies optimal FA values and determines the total number of SPGR andB 1 + $$ {B}_1^{+} $$ measurements needed to achieve a desiredT 1 $$ {T}_1 $$ precision.
Collapse
Affiliation(s)
- Gabriela Belsley
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUK
| | - Damian J. Tyler
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUK
| | - Matthew D. Robson
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUK
- PerspectumOxfordUK
| | - Elizabeth M. Tunnicliffe
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUK
| |
Collapse
|
4
|
Paajanen A, Hanhela M, Hänninen N, Nykänen O, Kolehmainen V, Nissi MJ. Fast Compressed Sensing of 3D Radial T 1 Mapping with Different Sparse and Low-Rank Models. J Imaging 2023; 9:151. [PMID: 37623683 PMCID: PMC10455972 DOI: 10.3390/jimaging9080151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/14/2023] [Accepted: 07/21/2023] [Indexed: 08/26/2023] Open
Abstract
Knowledge of the relative performance of the well-known sparse and low-rank compressed sensing models with 3D radial quantitative magnetic resonance imaging acquisitions is limited. We use 3D radial T1 relaxation time mapping data to compare the total variation, low-rank, and Huber penalty function approaches to regularization to provide insights into the relative performance of these image reconstruction models. Simulation and ex vivo specimen data were used to determine the best compressed sensing model as measured by normalized root mean squared error and structural similarity index. The large-scale compressed sensing models were solved by combining a GPU implementation of a preconditioned primal-dual proximal splitting algorithm to provide high-quality T1 maps within a feasible computation time. The model combining spatial total variation and locally low-rank regularization yielded the best performance, followed closely by the model combining spatial and contrast dimension total variation. Computation times ranged from 2 to 113 min, with the low-rank approaches taking the most time. The differences between the compressed sensing models are not necessarily large, but the overall performance is heavily dependent on the imaged object.
Collapse
Affiliation(s)
| | | | | | | | | | - Mikko J. Nissi
- Department of Technical Physics, University of Eastern Finland, 70211 Kuopio, Finland; (A.P.); (M.H.); (N.H.); (O.N.); (V.K.)
| |
Collapse
|
5
|
Konar AS, Paudyal R, Shah AD, Fung M, Banerjee S, Dave A, Lee N, Hatzoglou V, Shukla-Dave A. Qualitative and Quantitative Performance of Magnetic Resonance Image Compilation (MAGiC) Method: An Exploratory Analysis for Head and Neck Imaging. Cancers (Basel) 2022; 14:cancers14153624. [PMID: 35892883 PMCID: PMC9331960 DOI: 10.3390/cancers14153624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 01/27/2023] Open
Abstract
The present exploratory study investigates the performance of a new, rapid, synthetic MRI method for diagnostic image quality assessment and measurement of relaxometry metric values in head and neck (HN) tumors and normal-appearing masseter muscle. The multi-dynamic multi-echo (MDME) sequence was used for data acquisition, followed by synthetic image reconstruction on a 3T MRI scanner for 14 patients (3 untreated and 11 treated). The MDME enables absolute quantification of physical tissue properties, including T1 and T2, with a shorter scan time than the current state-of-the-art methods used for relaxation measurements. The vendor termed the combined package MAGnetic resonance imaging Compilation (MAGiC). In total, 48 regions of interest (ROIs) were analyzed, drawn on normal-appearing masseter muscle and tumors in the HN region. Mean T1 and T2 values obtained from normal-appearing muscle were 880 ± 52 ms and 46 ± 3 ms, respectively. Mean T1 and T2 values obtained from tumors were 1930 ± 422 ms and 77 ± 13 ms, respectively, for the untreated group, 1745 ± 410 ms and 107 ± 61 ms, for the treated group. A total of 1552 images from both synthetic MRI and conventional clinical imaging were assessed by the radiologists to provide the rating for T1w and T2w image contrasts. The synthetically generated qualitative T2w images were acceptable and comparable to conventional diagnostic images (93% acceptability rating for both). The acceptability ratings for MAGiC-generated T1w, and conventional images were 64% and 100%, respectively. The benefit of MAGiC in HN imaging is twofold, providing relaxometry maps in a clinically feasible time and the ability to generate a different combination of contrast images in a single acquisition.
Collapse
Affiliation(s)
- Amaresha Shridhar Konar
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; (A.S.K.); (R.P.)
| | - Ramesh Paudyal
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; (A.S.K.); (R.P.)
| | - Akash Deelip Shah
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; (A.D.S.); (V.H.)
| | - Maggie Fung
- General Electric Health Care, New York, NY 10065, USA; (M.F.); (S.B.)
| | | | - Abhay Dave
- Touro College of Osteopathic Medicine, New York, NY 10027, USA;
| | - Nancy Lee
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
| | - Vaios Hatzoglou
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; (A.D.S.); (V.H.)
| | - Amita Shukla-Dave
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; (A.S.K.); (R.P.)
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; (A.D.S.); (V.H.)
- Correspondence: ; Tel.: +1-212-639-3184
| |
Collapse
|
6
|
Quantitative Synthetic Magnetic Resonance Imaging for Brain Metastases: A Feasibility Study. Cancers (Basel) 2022; 14:cancers14112651. [PMID: 35681631 PMCID: PMC9179589 DOI: 10.3390/cancers14112651] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/16/2022] [Accepted: 05/20/2022] [Indexed: 02/01/2023] Open
Abstract
Simple Summary This preliminary study aims to characterize brain metastases (BM) using T1 and T2 maps generated from newer, rapid, synthetic MRI (MAGnetic resonance image Compilation; MAGiC) in a clinical setting. In addition, synthetic MR could provide contrast images analogous to standard T1- and T2-weighted images. The reproducibility and repeatability of this method have been previously established for brain imaging. This study reports and analyzes the quantitative T1 and T2 values for 11 BM patients (17 BM lesions) with a total of 82 regions of interest (ROIs) delineated by an experienced neuroradiologist. The initial results, which need to be further validated in a larger patient cohort, demonstrated the ability of T1 and T2 metric values to characterize BMs and normal-appearing brain tissues. The T1 and T2 metrics could be potential surrogate biomarkers for BM free water content (cellularity) and tumor morphology, respectively. Abstract The present preliminary study aims to characterize brain metastases (BM) using T1 and T2 maps generated from newer, rapid, synthetic MRI (MAGnetic resonance image Compilation; MAGiC) in a clinical setting. We acquired synthetic MRI data from 11 BM patients on a 3T scanner. A multiple-dynamic multiple-echo (MDME) sequence was used for data acquisition and synthetic image reconstruction, including post-processing. MDME is a multi-contrast sequence that enables absolute quantification of physical tissue properties, including T1 and T2, independent of the scanner settings. In total, 82 regions of interest (ROIs) were analyzed, which were obtained from both normal-appearing brain tissue and BM lesions. The mean values obtained from the 48 normal-appearing brain tissue regions and 34 ROIs of BM lesions (T1 and T2) were analyzed using standard statistical methods. The mean T1 and T2 values were 1143 ms and 78 ms, respectively, for normal-appearing gray matter, 701 ms and 64 ms for white matter, and 4206 ms and 390 ms for cerebrospinal fluid. For untreated BMs, the mean T1 and T2 values were 1868 ms and 100 ms, respectively, and 2211 ms and 114 ms for the treated group. The quantitative T1 and T2 values generated from synthetic MRI can characterize BM and normal-appearing brain tissues.
Collapse
|
7
|
Scope Crafts E, Lu H, Ye H, Wald LL, Zhao B. An efficient approach to optimal experimental design for magnetic resonance fingerprinting with B‐splines. Magn Reson Med 2022; 88:239-253. [DOI: 10.1002/mrm.29212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 01/30/2022] [Accepted: 02/08/2022] [Indexed: 11/05/2022]
Affiliation(s)
- Evan Scope Crafts
- Oden Institute for Computational Engineering and Sciences University of Texas at Austin Austin Texas USA
| | - Hengfa Lu
- Department of Biomedical Engineering University of Texas at Austin Austin Texas USA
| | - Huihui Ye
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering Zhejiang University Hangzhou Zhejiang China
- Center for Brain Imaging Science and Technology Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrumental Science, Zhejiang University Hangzhou Zhejiang China
| | - Lawrence L. Wald
- Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital Charlestown Massachusetts USA
- Department of Radiology Harvard Medical School Boston Massachusetts USA
- Harvard‐MIT Division of Health Sciences and Technology Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Bo Zhao
- Oden Institute for Computational Engineering and Sciences University of Texas at Austin Austin Texas USA
- Department of Biomedical Engineering University of Texas at Austin Austin Texas USA
| |
Collapse
|
8
|
Lie AL, Pan X, White TW, Vaghefi E, Donaldson PJ. Age-Dependent Changes in Total and Free Water Content of In Vivo Human Lenses Measured by Magnetic Resonance Imaging. Invest Ophthalmol Vis Sci 2021; 62:33. [PMID: 34293079 PMCID: PMC8300047 DOI: 10.1167/iovs.62.9.33] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Purpose To use magnetic resonance imaging (MRI) to measure age-dependent changes in total and free water in human lenses in vivo. Methods Sixty-four healthy adults aged 18 to 86 years were recruited, fitted with a 32-channel head receiver coil, and placed in a 3 Tesla clinical MR scanner. Scans of the crystalline lens were obtained using a volumetric interpolated breath-hold examination sequence with dual flip angles, which were corrected for field inhomogeneity post-acquisition using a B1-map obtained using a turbo-FLASH sequence. The spatial distribution and content of corrected total (ρlens) and free (T1) water along the lens optical axis were extracted using custom-written code. Results Lens total water distribution and content did not change with age (all P > 0.05). In contrast to total water, a gradient in free water content that was highest in the periphery relative to the center was present in lenses across all ages. However, this initially parabolic free water gradient gradually developed an enhanced central plateau, as indicated by increasing profile shape parameter values (anterior: 0.067/y, P = 0.004; posterior: 0.050/y, P = 0.020) and central free water content (1.932 ms/y, P = 0.022) with age. Conclusions MRI can obtain repeatable total and free water measurements of in vivo human lenses. The observation that the lens steady-state free, but not total, water gradient is abolished with age raises the possibility that alterations in protein-water interactions are an underlying cause of the degradation in lens optics and overall vision observed with aging.
Collapse
Affiliation(s)
- Alyssa L Lie
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Xingzheng Pan
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, New Zealand.,Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, United States
| | - Ehsan Vaghefi
- School of Optometry and Vision Science, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, New Zealand National Eye Centre, University of Auckland, New Zealand
| |
Collapse
|
9
|
Shridhar Konar A, Qian E, Geethanath S, Buonincontri G, Obuchowski NA, Fung M, Gomez P, Schulte R, Cencini M, Tosetti M, Schwartz LH, Shukla-Dave A. Quantitative imaging metrics derived from magnetic resonance fingerprinting using ISMRM/NIST MRI system phantom: An international multicenter repeatability and reproducibility study. Med Phys 2021; 48:2438-2447. [PMID: 33690905 DOI: 10.1002/mp.14833] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 02/04/2021] [Accepted: 02/23/2021] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To compare the bias and inherent reliability of the quantitative (T1 and T2 ) imaging metrics generated from the magnetic resonance fingerprinting (MRF) technique using the ISMRM/NIST system phantom in an international multicenter setting. METHOD ISMRM/NIST MRI system phantom provides standard reference T1 and T2 relaxation values (vendor-provided) for each of the 14 vials in T1 and T2 arrays. MRF-SSFP scans repeated over 30 days on GE 1.5 and 3.0 T scanners at three collaborative centers. MRF estimated T1, and T2 values averaged over 30 days were compared with the phantom vendor-provided and spin-echo (SE) based convention gold standard (GS) method. Repeatability and reproducibility were characterized by the within-case coefficient of variation (wCV) of the MRF data acquired over 30 days, along with the biases. RESULT For the wide ranges of MRF estimated T1 values, vials #1-8 (T1 relaxation time between 2033 and 184 ms) exhibited a wCV less than 3% and 4%, respectively, on 3.0 and 1.5 T scanners. T2 values in vials #1-8 (T2 relaxation, 1044-45 ms) have shown wCV to be <7% on both 3.0 and 1.5 T scanners. A stronger linear correlation overall for T1 (R2 = 0.9960 and 0.9963 at center-1 and center-2 on 3.0 T scanner, and R2 = 0.9951 and 0.9988 at center-1 and center-3 on 1.5 T scanner) compared to T2 (R2 = 0.9971 and 0.9972 at center-1 and center-2 on 3.0 T scanner, and R2 = 0.9815 and 0.9754 at center-1 and center-3 on 1.5 T scanner). Bland-Altman (BA) analysis showed MRF based T1 and T2 values were within the limit of agreement (LOA) except for one data point. The mean difference or bias and 95% lower bound (LB) and upper bound (UB) LOA are reported in the format; mean bias: 95% LB LOA: 95% UB LOA. The biases for T1 values were 21.34: -50.00: 92.69, 21.32: -47.29: 89.94 ms, and for T2 values were -19.88: -42.37: 2.61, -19.06: -43.58: 5.45 ms on 3.0 T scanner at center-1 and center-2, respectively. Similarly, on 1.5 T scanner biases for T1 values were 26.54: -53.41: 106.50, 9.997: -51.94: 71.94 ms, and for T2 values were -23.84: -135.40: 87.76, -37.30: 134.30: 59.73 ms at center-1 and center-3, respectively. Additionally, the correlation between the SE based GS and MRF estimated T1 and T2 values (R2 = 0.9969 and 0.9977) showed a similar trend as we observed between vendor-provided and MRF estimated T1 and T2 values (R2 = 0.9963 and 0.9972). In addition to correlation, BA analysis showed that all the vials are within the LOA between the GS and vendor-provided for the T1 values and except one vial for T2 . All the vials are within the LOA between GS and MRF except one vial in T1 and T2 array. The wCV for reproducibility was <3% for both T1 and T2 values in vials #1-8, for all the 14 vials, wCV calculated for reproducibility was <4% for T1 values and <5% for T2 . CONCLUSION This study shows that MRF is highly repeatable (wCV <4% for T1 and <7% for T2 ) and reproducible (wCV < 3% for both T1 and T2 ) in certain vials (vials #1-8).
Collapse
Affiliation(s)
- Amaresha Shridhar Konar
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Enlin Qian
- Columbia Magnetic Resonance Research Center, Columbia University in the City of New York, New York, NY, 10027, USA
| | - Sairam Geethanath
- Columbia Magnetic Resonance Research Center, Columbia University in the City of New York, New York, NY, 10027, USA
| | - Guido Buonincontri
- Imago7 Foundation and IRCCS Stella Maris Foundation, Pisa, PI, 56128, Italy
| | - Nancy A Obuchowski
- Department of Quantitative Health Sciences, Cleveland Clinic Foundation, Cleveland, OH, 44106, USA
| | | | - Pedro Gomez
- Munich School of Bioengineering, Technical University of Munich, Munich, BY, 85748, Germany
| | | | - Matteo Cencini
- Imago7 Foundation and IRCCS Stella Maris Foundation, Pisa, PI, 56128, Italy
| | - Michela Tosetti
- Imago7 Foundation and IRCCS Stella Maris Foundation, Pisa, PI, 56128, Italy
| | - Lawrence H Schwartz
- Department of Radiology, Columbia University Irving Medical Center and New York Presbyterian Hospital, New York, NY, 10032, USA
| | - Amita Shukla-Dave
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.,Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| |
Collapse
|
10
|
Mitchell DP, Hwang KP, Bankson JA, Jason Stafford R, Banerjee S, Takei N, Fuentes D. An information theory model for optimizing quantitative magnetic resonance imaging acquisitions. Phys Med Biol 2020; 65:225008. [PMID: 32947269 DOI: 10.1088/1361-6560/abb9f6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Acquisition parameter selection is currently performed empirically for many quantitative MRI (qMRI) acquisitions. Tuning parameters for different scan times, tissues, and resolutions requires some amount of trial and error. There is an opportunity to quantitatively optimize these acquisition parameters in order to minimize variability of quantitative maps and post-processing techniques such as synthetic image generation. The objective of this work is to introduce and evaluate a quantitative method for selecting parameters that minimize image variability. An information theory framework was developed for this purpose and applied to a 3D-quantification using an interleaved Look-Locker acquisition sequence with T2 preparation pulse (3D-QALAS) signal model for qMRI. In this framework, mutual information is used to measure the information gained by a measurement as a function of acquisition parameters, quantifying the information content of potential acquisitions and allowing informed parameter selection. The information theory framework was tested on artificial data generated from a representative mathematical phantom, measurements acquired on a qMRI multiparametric imaging standard phantom, and in vivo measurements in a human brain. The phantom measurements showed that higher mutual information calculated by the model correlated with smaller coefficient of variation in the reconstructed parametric maps, and in vivo measurements demonstrated that information-based calibration of acquisition parameters resulted in a decrease in parametric map variability consistent with model predictions.
Collapse
Affiliation(s)
- Drew P Mitchell
- Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America
| | | | | | | | | | | | | |
Collapse
|
11
|
Determinants of Intraparenchymal Infusion Distributions: Modeling and Analyses of Human Glioblastoma Trials. Pharmaceutics 2020; 12:pharmaceutics12090895. [PMID: 32967184 PMCID: PMC7559135 DOI: 10.3390/pharmaceutics12090895] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 01/01/2023] Open
Abstract
Intra-parenchymal injection and delivery of therapeutic agents have been used in clinical trials for brain cancer and other neurodegenerative diseases. The complexity of transport pathways in tissue makes it difficult to envision therapeutic agent distribution from clinical MR images. Computer-assisted planning has been proposed to mitigate risk for inadequate delivery through quantitative understanding of infusion characteristics. We present results from human studies and simulations of intratumoral infusions of immunotoxins in glioblastoma patients. Gd-DTPA and 124I-labeled human serum albumin (124I-HSA) were co-infused with the therapeutic, and their distributions measured in MRI and PET. Simulations were created by modeling tissue fluid mechanics and physiology and suggested that reduced distribution of tracer molecules within tumor is primarily related to elevated loss rates computed from DCE. PET-tracer on the other hand shows that the larger albumin molecule had longer but heterogeneous residence times within the tumor. We found over two orders of magnitude variation in distribution volumes for the same infusion volumes, with relative error ~20%, allowing understanding of even anomalous infusions. Modeling and measurement revealed that key determinants of flow include infusion-induced expansion and loss through compromised BBB. Opportunities are described to improve computer-assisted CED through iterative feedback between simulations and imaging.
Collapse
|
12
|
Haast RAM, Lau JC, Ivanov D, Menon RS, Uludağ K, Khan AR. Effects of MP2RAGE B 1+ sensitivity on inter-site T 1 reproducibility and hippocampal morphometry at 7T. Neuroimage 2020; 224:117373. [PMID: 32949709 DOI: 10.1016/j.neuroimage.2020.117373] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 09/11/2020] [Accepted: 09/12/2020] [Indexed: 01/19/2023] Open
Abstract
Most neuroanatomical studies are based on T1-weighted MR images, whose intensity profiles are not solely determined by the tissue's longitudinal relaxation times (T1), but also affected by varying non-T1 contributions, hampering data reproducibility. In contrast, quantitative imaging using the MP2RAGE sequence, for example, allows direct characterization of the brain based on the tissue property of interest. Combined with 7 Tesla (7T) MRI, this offers unique opportunities to obtain robust high-resolution brain data characterized by a high reproducibility, sensitivity and specificity. However, specific MP2RAGE parameter choices - e.g., to emphasize intracortical myelin-dependent contrast variations - can substantially impact image quality and cortical analyses through remnants of B1+-related intensity variations, as illustrated in our previous work. To follow up on this: we (1) validate this protocol effect using a dataset acquired with a particularly B1+ insensitive set of MP2RAGE parameters combined with parallel transmission excitation; and (2) extend our analyses to evaluate the effects on hippocampal morphometry. The latter remained unexplored initially, but can provide important insights related to generalizability and reproducibility of neurodegenerative research using 7T MRI. We confirm that B1+ inhomogeneities have a considerably variable effect on cortical T1 estimates, as well as on hippocampal morphometry depending on the MP2RAGE setup. While T1 differed substantially across datasets initially, we show the inter-site T1 comparability improves after correcting for the spatially varying B1+ field using a separately acquired Sa2RAGE B1+ map. Finally, removal of B1+ residuals affects hippocampal volumetry and boundary definitions, particularly near structures characterized by strong intensity changes (e.g. cerebral spinal fluid). Taken together, we show that the choice of MP2RAGE parameters can impact T1 comparability across sites and present evidence that hippocampal segmentation results are modulated by B1+ inhomogeneities. This calls for careful (1) consideration of sequence parameters when setting acquisition protocols, as well as (2) acquisition of a B1+ map to correct MP2RAGE data for potential B1+ variations to allow comparison across datasets.
Collapse
Affiliation(s)
- Roy A M Haast
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, Western University, 1151 Richmond St. N., London, ON N6A 5B7, Canada.
| | - Jonathan C Lau
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, Western University, 1151 Richmond St. N., London, ON N6A 5B7, Canada; Department of Clinical Neurological Sciences, Division of Neurosurgery, Western University, 1151 Richmond St. N., London, ON N6A 5B7, Canada
| | - Dimo Ivanov
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, PO Box 616, 6200 MD, Maastricht, Netherlands
| | - Ravi S Menon
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, Western University, 1151 Richmond St. N., London, ON N6A 5B7, Canada; Brain and Mind Institute, Western University, 1151 Richmond St. N., London, ON N6A 5B7, Canada; Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, 1151 Richmond St. N., London, ON N6A 5B7, Canada
| | - Kâmil Uludağ
- IBS Center for Neuroscience Imaging Research, Sungkyunkwan University, Seobu-ro, 2066, Jangan-gu, Suwon, South Korea; Department of Biomedical Engineering, N Center, Sungkyunkwan University, Seobu-ro, 2066, Jangan-gu, Suwon, South Korea; Techna Institute and Koerner Scientist in MR Imaging, University Health Network, 100 College St, Toronto, ON M5G 1L5, Canada
| | - Ali R Khan
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, Western University, 1151 Richmond St. N., London, ON N6A 5B7, Canada; Brain and Mind Institute, Western University, 1151 Richmond St. N., London, ON N6A 5B7, Canada; Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, 1151 Richmond St. N., London, ON N6A 5B7, Canada
| |
Collapse
|
13
|
Hilbert T, Xia D, Block KT, Yu Z, Lattanzi R, Sodickson DK, Kober T, Cloos MA. Magnetization transfer in magnetic resonance fingerprinting. Magn Reson Med 2020; 84:128-141. [PMID: 31762101 PMCID: PMC7083689 DOI: 10.1002/mrm.28096] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/18/2019] [Accepted: 11/04/2019] [Indexed: 01/28/2023]
Abstract
PURPOSE To study the effects of magnetization transfer (MT, in which a semi-solid spin pool interacts with the free pool), in the context of magnetic resonance fingerprinting (MRF). METHODS Simulations and phantom experiments were performed to study the impact of MT on the MRF signal and its potential influence on T1 and T2 estimation. Subsequently, an MRF sequence implementing off-resonance MT pulses and a dictionary with an MT dimension, generated by incorporating a two-pool model, were used to estimate the fractional pool size in addition to the B 1 + , T1 , and T2 values. The proposed method was evaluated in the human brain. RESULTS Simulations and phantom experiments showed that an MRF signal obtained from a cross-linked bovine serum sample is influenced by MT. Using a dictionary based on an MT model, a better match between simulations and acquired MR signals can be obtained (NRMSE 1.3% vs. 4.7%). Adding off-resonance MT pulses can improve the differentiation of MT from T1 and T2 . In vivo results showed that MT affects the MRF signals from white matter (fractional pool-size ~16%) and gray matter (fractional pool-size ~10%). Furthermore, longer T1 (~1060 ms vs. ~860 ms) and T2 values (~47 ms vs. ~35 ms) can be observed in white matter if MT is accounted for. CONCLUSION Our experiments demonstrated a potential influence of MT on the quantification of T1 and T2 with MRF. A model that encompasses MT effects can improve the accuracy of estimated relaxation parameters and allows quantification of the fractional pool size.
Collapse
Affiliation(s)
- Tom Hilbert
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Ding Xia
- Center for Advanced Imaging Innovation and Research (CAIR), 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
| | - Kai Tobias Block
- Center for Advanced Imaging Innovation and Research (CAIR), 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
- Department of Radiology, University Hospital Basel, Basel, Switzerland
| | - Zidan Yu
- Center for Advanced Imaging Innovation and Research (CAIR), 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
- The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, USA
| | - Riccardo Lattanzi
- Center for Advanced Imaging Innovation and Research (CAIR), 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
- The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, USA
| | - Daniel K Sodickson
- Center for Advanced Imaging Innovation and Research (CAIR), 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
- The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, USA
| | - Tobias Kober
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
- Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Martijn A Cloos
- Center for Advanced Imaging Innovation and Research (CAIR), 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
- The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, USA
| |
Collapse
|
14
|
Gomolka RS, Ciritsis A, Rossi C. 23 Na-T 1 quantification with saturation recovery TrueFISP and variable flip angle GRE at 3T: A phantom study. Magn Reson Med 2020; 84:3300-3307. [PMID: 32544302 DOI: 10.1002/mrm.28333] [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: 11/29/2019] [Revised: 04/11/2020] [Accepted: 05/01/2020] [Indexed: 11/05/2022]
Abstract
PURPOSE The aim of the current study was to compare the reproducibility of sodium (23 Na)-T1 estimation using a centric-reordered saturation recovery (SR) true fast imaging with steady-state precession (TrueFISP) and a variable flip angle (VFA) spoiled gradient echo (GRE). Additionally, we evaluated the effect of spatial averaging on 23 Na-T1 estimation by the two methods. METHODS Measurements were performed in the phantom, consisting of 10 dm3 volume rectangular polyethylene container filled with distilled water solution of 0.6% NaCl + 0.004% CuSO4 , using a dual-tunable 23 Na/1 H coil at 3 Tesla. 23 Na images were acquired for FOV = 384 × 384 mm2 and voxel size = 6 × 6 × 6 mm3 using: (1) TrueFISP: TR/TE = 900/1.5 ms, flip angle = 90°, bandwidth = 450 Hz/px, and (2) GRE: TR/TE = 30/1.5 ms, bandwidth = 350 Hz/px. 23 Na-T1 weightings were obtained with nonselective saturation prepulses delayed from the center of the k-space acquisition by 25/40/60/130/280 ms (SR-TrueFISP) and by applying different nominal flip angles: 10°/30°/50°/70°/90° (VFA-GRE). Both sequences were acquired twice, applying 20 and 30 spatial averages. The resulting images were B1 -corrected with a double-angle GRE method. RESULTS Image acquisition varied from 5:41 to 9:37 for TrueFISP and from 12:48 to 19:12 min for GRE using 20 and 30 spatial averages, respectively. Higher averaging increased the acquisition time by 53% and mean SNR at scan < 10%, without an effect on 23 Na-T1 estimations with both methods (SR-Truefisp |Δ| = 1.58 ms, VFA-GRE |Δ| = 0.53 ms; for SNR P < .001). Overall, mean ± SD of 23 Na-T1 was found as 51 ± 3 ms with SR-TrueFISP and 53 ± 2 ms with VFA-GRE. CONCLUSION Both SR-TrueFISP and VFA-GRE provided similar 23 Na-T1 estimates based on the phantom measurements with isotropic resolution.
Collapse
Affiliation(s)
- Ryszard S Gomolka
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zürich, Switzerland
| | - Alexander Ciritsis
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zürich, Switzerland
| | - Cristina Rossi
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zürich, Switzerland
| |
Collapse
|
15
|
Olsson H, Andersen M, Lätt J, Wirestam R, Helms G. Reducing bias in dual flip angle T
1
‐mapping in human brain at 7T. Magn Reson Med 2020; 84:1347-1358. [DOI: 10.1002/mrm.28206] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/19/2020] [Accepted: 01/20/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Hampus Olsson
- Department of Medical Radiation Physics Clinical Sciences Lund Lund University Lund Sweden
| | | | - Jimmy Lätt
- Center for Medical Imaging and Physiology Skane University Hospital Lund Sweden
| | - Ronnie Wirestam
- Department of Medical Radiation Physics Clinical Sciences Lund Lund University Lund Sweden
| | - Gunther Helms
- Department of Medical Radiation Physics Clinical Sciences Lund Lund University Lund Sweden
| |
Collapse
|
16
|
Oros-Peusquens AM, Loução R, Abbas Z, Gras V, Zimmermann M, Shah NJ. A Single-Scan, Rapid Whole-Brain Protocol for Quantitative Water Content Mapping With Neurobiological Implications. Front Neurol 2019; 10:1333. [PMID: 31920951 PMCID: PMC6934004 DOI: 10.3389/fneur.2019.01333] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/02/2019] [Indexed: 12/16/2022] Open
Abstract
Water concentration is tightly regulated in the healthy human brain and changes only slightly with age and gender in healthy subjects. Consequently, changes in water content are important for the characterization of disease. MRI can be used to measure changes in brain water content, but as these changes are usually in the low percentage range, highly accurate and precise methods are required for detection. The method proposed here is based on a long-TR (10 s) multiple-echo gradient-echo measurement with an acquisition time of 7:21 min. Using such a long TR ensures that there is no T1 weighting, meaning that the image intensity at zero echo time is only proportional to the water content, the transmit field, and to the receive field. The receive and transmit corrections, which are increasingly large at higher field strengths and for highly segmented coil arrays, are multiplicative and can be approached heuristically using a bias field correction. The method was tested on 21 healthy volunteers at 3T field strength. Calibration using cerebral-spinal fluid values (~100% water content) resulted in mean values and standard deviations of the water content distribution in white matter and gray matter of 69.1% (1.7%) and 83.7% (1.2%), respectively. Measured distributions were coil-independent, as seen by using either a 12-channel receiver coil or a 32-channel receiver coil. In a test-retest investigation using 12 scans on one volunteer, the variation in the mean value of water content for different tissue types was ~0.3% and the mean voxel variability was ~1%. Robustness against reduced SNR was assessed by comparing results for 5 additional volunteers at 1.5T and 3T. Furthermore, water content distribution in gray matter is investigated and regional contrast reported for the first time. Clinical applicability is illustrated with data from one stroke patient and one brain tumor patient. It is anticipated that this fast, stable, easy-to-use, high-quality mapping method will facilitate routine quantitative MR imaging of water content.
Collapse
Affiliation(s)
| | - Ricardo Loução
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany
| | - Zaheer Abbas
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany
| | - Vincent Gras
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany
| | - Markus Zimmermann
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany
| | - N J Shah
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany.,Institute of Neurosciences and Medicine 11 (INM-11), JARA, Forschungszentrum Jülich, Jülich, Germany.,JARA - BRAIN - Translational Medicine, Aachen, Germany.,Department of Neurology, RWTH Aachen University, Aachen, Germany
| |
Collapse
|
17
|
Drisis S, El Adoui M, Flamen P, Benjelloun M, Dewind R, Paesmans M, Ignatiadis M, Bali M, Lemort M. Early prediction of neoadjuvant treatment outcome in locally advanced breast cancer using parametric response mapping and radial heterogeneity from breast MRI. J Magn Reson Imaging 2019; 51:1403-1411. [PMID: 31737963 DOI: 10.1002/jmri.26996] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 10/25/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Early prediction of nonresponse is essential in order to avoid inefficient treatments. PURPOSE To evaluate if parametrical response mapping (PRM)-derived biomarkers could predict early morphological response (EMR) and pathological complete response (pCR) 24-72 hours after initiation of chemotherapy treatment and whether concentric analysis of nonresponding PRM regions could better predict response. STUDY TYPE This was a retrospective analysis of prospectively acquired cohort, nonrandomized, monocentric, diagnostic study. POPULATION Sixty patients were initially recruited, with 39 women participating in the final cohort. FIELD STRENGTH/SEQUENCE A 1.5T scanner was used for MRI examinations. ASSESSMENT Dynamic contrast-enhanced (DCE)-MR images were acquired at baseline (timepoint 1, TP1), 24-72 hours after the first chemotherapy (TP2), and after the end of anthracycline treatment (TP3). PRM was performed after fusion of T1 subtraction images from TP1 and TP2 using an affine registration algorithm. Pixels with an increase of more than 10% of their value (PRMdce+) were corresponding nonresponding regions of the tumor. Patients with a decrease of maximum diameter (%dDmax) between TP1 and TP3 of more than 30% were defined as EMR responders. pCR patients achieved a residual cancer burden score of 0. STATISTICAL TESTS T-test, receiver operating characteristic (ROC) curves, and logistic regression were used for the analysis. RESULTS PRM showed a statistical difference between pCR response groups (P < 0.01) and AUC of 0.88 for the prediction of non-pCR. Logistic regression analysis demonstrated that PRMdce+ and Grade II were significant (P < 0.01) for non-pCR prediction (AUC = 0.94). Peripheral tumor region demonstrated higher performance for the prediction of non-pCR (AUC = 0.85) than intermediate and central zones; however, statistical comparison showed no significant difference. DATA CONCLUSION PRM could be predictive of non-pCR 24-72 hours after initiation of chemotherapy treatment. Moreover, the peripheral region showed increased AUC for non-pCR prediction and increased signal intensity during treatment for non-pCR tumors, information that could be used for optimal tissue sampling. LEVEL OF EVIDENCE 1 Technical Efficacy Stage: 4 J. Magn. Reson. Imaging 2020;51:1403-1411.
Collapse
Affiliation(s)
| | - Mohammed El Adoui
- Medical Imaging Department, Polytechnic University of Mons, Mons, Belgium
| | - Patrick Flamen
- Nuclear Department, Institute Jules Bordet, Brussels, Belgium
| | | | - Roland Dewind
- Pathology Department, Institute Jules Bordet, Brussels, Belgium
| | - Mariane Paesmans
- Statistics Department, Institute Jules Bordet, Brussels, Belgium
| | | | - Maria Bali
- Radiology Department, Institute Jules Bordet, Brussels, Belgium
| | - Marc Lemort
- Radiology Department, Institute Jules Bordet, Brussels, Belgium
| |
Collapse
|
18
|
He Y, Qin S, Dyer BA, Zhang H, Zhao L, Chen T, Zheng F, Sun Y, Shi L, Rong Y, Qiu J. Characterizing mechanical and medical imaging properties of polyvinyl chloride-based tissue-mimicking materials. J Appl Clin Med Phys 2019; 20:176-183. [PMID: 31207035 PMCID: PMC6612694 DOI: 10.1002/acm2.12661] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 04/25/2019] [Accepted: 05/23/2019] [Indexed: 01/09/2023] Open
Abstract
Polyvinyl chloride (PVC) is a commonly used tissue‐mimicking material (TMM) for phantom construction using 3D printing technology. PVC‐based TMMs consist of a mixture of PVC powder and dioctyl terephthalate as a softener. In order to allow the clinical use of a PVC‐based phantom use across CT and magnetic resonance imaging (MRI) imaging platforms, we evaluated the mechanical and physical imaging characteristics of ten PVC samples. The samples were made with different PVC‐softener ratios to optimize phantom bioequivalence with physiologic human tissue. Phantom imaging characteristics, including computed tomography (CT) number, MRI relaxation time, and mechanical properties (e.g., Poisson’s ratio and elastic modulus) were quantified. CT number varied over a range of approximately −10 to 110 HU. The relaxation times of the T1‐weighted and T2‐weighted images were 206.81 ± 17.50 and 20.22 ± 5.74 ms, respectively. Tensile testing was performed to evaluate mechanical properties on the three PVC samples that were closest to human tissue. The elastic moduli for these samples ranged 7.000–12.376 MPa, and Poisson’s ratios were 0.604–0.644. After physical and imaging characterization of the various PVC‐based phantoms, we successfully produced a bioequivalent phantom compatible with multimodal imaging platforms for machine calibration and image optimization/benchmarking. By combining PVC with 3D printing technologies, it is possible to construct imaging phantoms simulating human anatomies with tissue equivalency.
Collapse
Affiliation(s)
- Yaoyao He
- Medical engineering and technology center, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Imaging-X Joint laboratory, Taian, China.,Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China
| | - Shengxue Qin
- College of Mechanical and Electronic Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Brandon A Dyer
- Department of Radiation Oncology, University of California Davis Medical Center, Sacramento, CA, USA
| | - Hongbin Zhang
- College of Mechanical and Electronic Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Lifen Zhao
- School of Material Science and Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Tiao Chen
- Medical engineering and technology center, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Imaging-X Joint laboratory, Taian, China.,Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Department of Radiology, Hubei Cancer Hospital, Wuhan, China
| | - Fenglian Zheng
- Medical engineering and technology center, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Imaging-X Joint laboratory, Taian, China.,Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China
| | - Yong Sun
- Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China
| | - Liting Shi
- Medical engineering and technology center, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Imaging-X Joint laboratory, Taian, China.,Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China
| | - Yi Rong
- Department of Radiation Oncology, University of California Davis Medical Center, Sacramento, CA, USA
| | - Jianfeng Qiu
- Medical engineering and technology center, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China.,Imaging-X Joint laboratory, Taian, China.,Radiology Department, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, China
| |
Collapse
|
19
|
Assländer J, Lattanzi R, Sodickson DK, Cloos MA. Optimized quantification of spin relaxation times in the hybrid state. Magn Reson Med 2019; 82:1385-1397. [PMID: 31189025 DOI: 10.1002/mrm.27819] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 04/01/2019] [Accepted: 04/29/2019] [Indexed: 01/08/2023]
Abstract
PURPOSE The optimization and analysis of spin ensemble trajectories in the hybrid state-a state in which the direction of the magnetization adiabatically follows the steady state while the magnitude remains in a transient state. METHODS Numerical optimizations were performed to find spin ensemble trajectories that minimize the Cramér-Rao bound for T 1 -encoding, T 2 -encoding, and their weighted sum, respectively, followed by a comparison between the Cramér-Rao bounds obtained with our optimized spin-trajectories, Look-Locker sequences, and multi-spin-echo methods. Finally, we experimentally tested our optimized spin trajectories with in vivo scans of the human brain. RESULTS After a nonrecurring inversion segment on the southern half of the Bloch sphere, all optimized spin trajectories pursue repetitive loops on the northern hemisphere in which the beginning of the first and the end of the last loop deviate from the others. The numerical results obtained in this work align well with intuitive insights gleaned directly from the governing equation. Our results suggest that hybrid-state sequences outperform traditional methods. Moreover, hybrid-state sequences that balance T 1 - and T 2 -encoding still result in near optimal signal-to-noise efficiency for each relaxation time. Thus, the second parameter can be encoded at virtually no extra cost. CONCLUSIONS We provided new insights into the optimal encoding processes of spin relaxation times in order to guide the design of robust and efficient pulse sequences. We found that joint acquisitions of T 1 and T 2 in the hybrid state are substantially more efficient than sequential encoding techniques.
Collapse
Affiliation(s)
- Jakob Assländer
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York.,Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York
| | - Riccardo Lattanzi
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York.,Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York.,Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York
| | - Daniel K Sodickson
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York.,Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York.,Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York
| | - Martijn A Cloos
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York.,Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, New York.,Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, New York
| |
Collapse
|
20
|
Petersen A, Deoni S, Müller HG. Fréchet estimation of time-varying covariance matrices from sparse data, with application to the regional co-evolution of myelination in the developing brain. Ann Appl Stat 2019. [DOI: 10.1214/18-aoas1195] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
21
|
Ramos-Llorden G, Vegas-Sanchez-Ferrero G, Bjork M, Vanhevel F, Parizel PM, San Jose Estepar R, den Dekker AJ, Sijbers J. NOVIFAST: A Fast Algorithm for Accurate and Precise VFA MRI Mapping. IEEE TRANSACTIONS ON MEDICAL IMAGING 2018; 37:2414-2427. [PMID: 29993537 PMCID: PMC6277233 DOI: 10.1109/tmi.2018.2833288] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In quantitative magnetic resonance mapping, the variable flip angle (VFA) steady state spoiled gradient recalled echo (SPGR) imaging technique is popular as it provides a series of high resolution weighted images in a clinically feasible time. Fast, linear methods that estimate maps from these weighted images have been proposed, such as DESPOT1 and iterative re-weighted linear least squares. More accurate, non-linear least squares (NLLS) estimators are in play, but these are generally much slower and require careful initialization. In this paper, we present NOVIFAST, a novel NLLS-based algorithm specifically tailored to VFA SPGR mapping. By exploiting the particular structure of the SPGR model, a computationally efficient, yet accurate and precise map estimator is derived. Simulation and in vivo human brain experiments demonstrate a twenty-fold speed gain of NOVIFAST compared with conventional gradient-based NLLS estimators while maintaining a high precision and accuracy. Moreover, NOVIFAST is eight times faster than the efficient implementations of the variable projection (VARPRO) method. Furthermore, NOVIFAST is shown to be robust against initialization.
Collapse
|
22
|
Lee Y, Callaghan MF, Acosta-Cabronero J, Lutti A, Nagy Z. Establishing intra- and inter-vendor reproducibility of T1
relaxation time measurements with 3T MRI. Magn Reson Med 2018; 81:454-465. [DOI: 10.1002/mrm.27421] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/28/2018] [Accepted: 06/04/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Yoojin Lee
- Laboratory for Social and Neural Systems Research; University of Zurich; Zürich Switzerland
| | - Martina F. Callaghan
- Wellcome Centre for Human Neuroimaging; UCL Institute of Neurology; London United Kingdom
| | - Julio Acosta-Cabronero
- Wellcome Centre for Human Neuroimaging; UCL Institute of Neurology; London United Kingdom
| | - Antoine Lutti
- Laboratory for Research in Neuroimaging, Department of Clinical Neuroscience,; Lausanne University Hospital and University of Lausanne; Lausanne Switzerland
| | - Zoltan Nagy
- Laboratory for Social and Neural Systems Research; University of Zurich; Zürich Switzerland
| |
Collapse
|
23
|
Brady ML, Coffield KS, Kuehl TJ, Raghavan R, Speights VO, Patel B, Wilson S, Wilson M, Odland RM. A pilot study in intraparenchymal therapy delivery in the prostate: a comparison of delivery with a porous needle vs standard needle. BMC Urol 2018; 18:66. [PMID: 30055610 PMCID: PMC6064133 DOI: 10.1186/s12894-018-0378-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 06/20/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND New biologic therapies directly injected into the prostate are in clinical trials for prostatic diseases. There is a need to understand distribution of injected therapies as a function of prostatic anatomy, physiology, and device design. METHODS A needle with a porous length of customizable-length was tested and its performance compared with a standard needle. Injections of magnetic resonance contrast reagent were placed into ex-vivo human prostates after surgical excision in standard of care therapy for invasive bladder cancer patients. Magnetic resonance images were acquired using sequences to quantify volume delivered, distributed, and backflow. RESULTS Magnetic resonance images analysis revealed heterogeneity distribution with injection into the specimens. There was low resistance to flow along ductal pathways and high resistance to flow into glandular nodules and smooth muscle/fibrous parenchyma. Data confirm previous studies showing injection loss via urethra backflow, urethra, and prostatic ducts. Tissue fraction of dose was significantly higher with porous needle compared with standard needle (p = .03). We found that a greater volume of distribution divided by the amount infused (Vd/Vi) increased by 80% with the porous needle, though no statistically significant association due to small sample size. CONCLUSIONS This study demonstrated that prostatic tissue is anatomically heterogenic and limits distribution of needle injection. There is greater distribution in the ex-vivo prostate using a porous needle. The complexity of intra prostatic flow pathways suggests preoperative imaging and pre-treatment planning will enhance therapy.
Collapse
Affiliation(s)
| | - King Scott Coffield
- Department of Surgery, Division of Urology, Scott & White Medical Center, Temple, TX, USA. .,Texas A&M Health Science Center College of Medicine, Temple, TX, USA.
| | - Thomas J Kuehl
- Department of Obstetrics & Gynecology, Scott & White Medical Center, Temple, TX, USA.,Departments of Obstetrics & Gynecology, Pediatrics, and Molecular & Cellular Medicine, Texas A&M Health Science Center College of Medicine, Temple, TX, USA
| | | | - V O Speights
- Department of Pathology, Scott & White Medical Center, Temple, TX, USA.,Texas A&M Health Science Center College of Medicine, Temple, TX, USA
| | - Belur Patel
- Department of Surgery, Division of Urology, Scott & White Medical Center, Temple, TX, USA.,Texas A&M Health Science Center College of Medicine, Temple, TX, USA
| | | | | | - Rick M Odland
- Twin Star TDS, LLC, Lexington, KY, USA.,Department of Otolaryngology, Hennepin County Medical Center, University of Minnesota, Minneapolis, MN, USA
| |
Collapse
|
24
|
Brady ML, Raghavan R, Mata J, Wilson M, Wilson S, Odland RM, Broaddus WC. Large-Volume Infusions into the Brain: A Comparative Study of Catheter Designs. Stereotact Funct Neurosurg 2018; 96:135-141. [PMID: 30021213 PMCID: PMC6093288 DOI: 10.1159/000488324] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 03/06/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS "Whole-brain" infusions have emerged as a potential need with the promise of disease-modifying therapies for neurodegenerative diseases. In addition, several current clinical trials in brain cancer utilize direct delivery of drugs that are required to fill large volumes. Such requirements may not be well served by conventional single port catheters with their "point source" of delivery. Our aim is to examine infusions into large volumes of heterogeneous tissue, aiming for uniformity of distribution. METHODS A porous catheter (porous brain infusion catheter, PBIC), designed by Twin Star TDS LLC, for brain infusions was developed for this study and compared with another convection-enhanced delivery catheter (SmartFlowTM NGS-NC-03 from MRI Interventions, a step end-port catheter, SEPC) in current use in clinical trials. The studies were in vivo in porcine brain. A total of 8 pigs were used: the size of the pig brain limited the porous length to 15 mm. The placements of the tips of the two catheters were chosen to be the same (at the respective brain hemispheres). RESULTS The PBIC and SEPC both performed comparably and well, with the PBIC having some advantage in effecting larger distributions: p ∼ 0.045, with 5 infusions from each. CONCLUSIONS Given the performance of the PBIC, it would be highly appropriate to use the device for therapeutic infusions in human clinical trials to assess its capability for large-volume infusions.
Collapse
Affiliation(s)
| | | | - Jaime Mata
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia, USA
| | | | | | - Rick M Odland
- Twin Star TDS, Lexington, Kentucky, USA
- Hennepin County Medical Center, Minneapolis, Minnesota, USA
| | - William C Broaddus
- Department of Neurosurgery, Medical College of Virginia/Virginia Commonwealth University, Richmond, Virginia, USA
| |
Collapse
|
25
|
van Rijssel MJ, Pluim JPW, Luijten PR, Gilhuijs KGA, Raaijmakers AJE, Klomp DWJ. Estimating B 1+ in the breast at 7 T using a generic template. NMR IN BIOMEDICINE 2018; 31:e3911. [PMID: 29570887 PMCID: PMC5947628 DOI: 10.1002/nbm.3911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 01/30/2018] [Accepted: 01/30/2018] [Indexed: 06/08/2023]
Abstract
Dynamic contrast-enhanced MRI is the workhorse of breast MRI, where the diagnosis of lesions is largely based on the enhancement curve shape. However, this curve shape is biased by RF transmit (B1+ ) field inhomogeneities. B1+ field information is required in order to correct these. The use of a generic, coil-specific B1+ template is proposed and tested. Finite-difference time-domain simulations for B1+ were performed for healthy female volunteers with a wide range of breast anatomies. A generic B1+ template was constructed by averaging simulations based on four volunteers. Three-dimensional B1+ maps were acquired in 15 other volunteers. Root mean square error (RMSE) metrics were calculated between individual simulations and the template, and between individual measurements and the template. The agreement between the proposed template approach and a B1+ mapping method was compared against the agreement between acquisition and reacquisition using the same mapping protocol. RMSE values (% of nominal flip angle) comparing individual simulations with the template were in the range 2.00-4.01%, with mean 2.68%. RMSE values comparing individual measurements with the template were in the range8.1-16%, with mean 11.7%. The agreement between the proposed template approach and a B1+ mapping method was only slightly worse than the agreement between two consecutive acquisitions using the same mapping protocol in one volunteer: the range of agreement increased from ±16% of the nominal angle for repeated measurement to ±22% for the B1+ template. With local RF transmit coils, intersubject differences in B1+ fields of the breast are comparable to the accuracy of B1+ mapping methods, even at 7 T. Consequently, a single generic B1+ template suits subjects over a wide range of breast anatomies, eliminating the need for a time-consuming B1+ mapping protocol.
Collapse
|
26
|
Bane O, Hectors S, Wagner M, Arlinghaus LL, Aryal M, Cao Y, Chenevert T, Fennessy F, Huang W, Hylton N, Kalpathy-Cramer J, Keenan K, Malyarenko D, Mulkern R, Newitt D, Russek SE, Stupic KF, Tudorica A, Wilmes L, Yankeelov TE, Yen YF, Boss M, Taouli B. Accuracy, repeatability, and interplatform reproducibility of T 1 quantification methods used for DCE-MRI: Results from a multicenter phantom study. Magn Reson Med 2018; 79:2564-2575. [PMID: 28913930 PMCID: PMC5821553 DOI: 10.1002/mrm.26903] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 08/14/2017] [Accepted: 08/16/2017] [Indexed: 02/05/2023]
Abstract
PURPOSE To determine the in vitro accuracy, test-retest repeatability, and interplatform reproducibility of T1 quantification protocols used for dynamic contrast-enhanced MRI at 1.5 and 3 T. METHODS A T1 phantom with 14 samples was imaged at eight centers with a common inversion-recovery spin-echo (IR-SE) protocol and a variable flip angle (VFA) protocol using seven flip angles, as well as site-specific protocols (VFA with different flip angles, variable repetition time, proton density, and Look-Locker inversion recovery). Factors influencing the accuracy (deviation from reference NMR T1 measurements) and repeatability were assessed using general linear mixed models. Interplatform reproducibility was assessed using coefficients of variation. RESULTS For the common IR-SE protocol, accuracy (median error across platforms = 1.4-5.5%) was influenced predominantly by T1 sample (P < 10-6 ), whereas test-retest repeatability (median error = 0.2-8.3%) was influenced by the scanner (P < 10-6 ). For the common VFA protocol, accuracy (median error = 5.7-32.2%) was influenced by field strength (P = 0.006), whereas repeatability (median error = 0.7-25.8%) was influenced by the scanner (P < 0.0001). Interplatform reproducibility with the common VFA was lower at 3 T than 1.5 T (P = 0.004), and lower than that of the common IR-SE protocol (coefficient of variation 1.5T: VFA/IR-SE = 11.13%/8.21%, P = 0.028; 3 T: VFA/IR-SE = 22.87%/5.46%, P = 0.001). Among the site-specific protocols, Look-Locker inversion recovery and VFA (2-3 flip angles) protocols showed the best accuracy and repeatability (errors < 15%). CONCLUSIONS The VFA protocols with 2 to 3 flip angles optimized for different applications achieved acceptable balance of extensive spatial coverage, accuracy, and repeatability in T1 quantification (errors < 15%). Further optimization in terms of flip-angle choice for each tissue application, and the use of B1 correction, are needed to improve the robustness of VFA protocols for T1 mapping. Magn Reson Med 79:2564-2575, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Octavia Bane
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai,Radiology, Icahn School of Medicine at Mount Sinai
| | - Stefanie Hectors
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai,Radiology, Icahn School of Medicine at Mount Sinai
| | - Mathilde Wagner
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai,Radiology, Icahn School of Medicine at Mount Sinai
| | | | | | - Yue Cao
- Radiation Oncology, University of Michigan
| | | | | | - Wei Huang
- Advanced Imaging Research Center, Knight Cancer Institute, Oregon Health and Science University
| | - Nola Hylton
- Radiology, University of California San Francisco
| | | | | | | | | | - David Newitt
- Radiology, University of California San Francisco
| | | | | | | | - Lisa Wilmes
- Radiology, University of California San Francisco
| | | | - Yi-Fei Yen
- Radiology, Massachusetts General Hospital
| | | | - Bachir Taouli
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai,Radiology, Icahn School of Medicine at Mount Sinai
| |
Collapse
|
27
|
Drisis S, Flamen P, Ignatiadis M, Metens T, Chao SL, Chintinne M, Lemort M. Total choline quantification measured by 1H MR spectroscopy as early predictor of response after neoadjuvant treatment for locally advanced breast cancer: The impact of immunohistochemical status. J Magn Reson Imaging 2018; 48:982-993. [PMID: 29659077 DOI: 10.1002/jmri.26042] [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: 01/05/2018] [Accepted: 03/21/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Validation of new biomarkers is essential for the early evaluation of neoadjuvant treatments. PURPOSE To determine whether measurements of total choline (tCho) by 1H spectroscopy could predict morphological or pathological complete response (pCR) of neoadjuvant treatment and whether breast cancer subgroups are related to prediction accuracy. STUDY TYPE Prospective, nonrandomized, monocentric, diagnostic study. POPULATION Sixty patients were initially included with 39 women participating in the final cohort. FIELD STRENGTH/SEQUENCE A 1.5T scanner was used for acquisition and MRS was performed using the syngo GRACE sequence. ASSESSMENT MRS and MRI examinations were performed at baseline (TP1), 24-72 hours after first chemotherapy (TP2), after the end of anthracycline treatment (TP3), and MRI only after the end of taxane treatment (TP4). Early (EMR) and late (LMR) morphological response were defined as %ΔDmax13 or %ΔDmax14, respectively. Responders were patients with %ΔDmax >30. Pathological complete response (pCR) patients achieved a residual cancer burden score of 0. STATISTICAL TESTS T-test, receiver operating characteristic (ROC) curves, multiple regression, logistic regression, one-way analysis of variance (ANOVA) analysis were used for the analysis. RESULTS At TP1 there was a significant difference between response groups for tCho1 concerning EMR prediction (P = 0.05) and pCR (P < 0.05) and for Kep 1 (P = 0.03) concerning LMR prediction. At TP2, no modification of tCho and other parameters could predict response. At TP3, ΔtCho, ΔDmax, and ΔVol could predict LMR (P < 0.05 for all parameters), pCR (P < 0.05 for all parameters), and ΔKtrans could predict only pCR (P = 0.04). Logistic regression at baseline showed the highest area under the curve (AUC) of 0.9 for prediction of pCR. The triple negative (TN) subgroup showed significantly higher tCho at baseline (P = 0.02) and higher ΔtCho levels at TP3 (P < 0.05). DATA CONCLUSION Baseline measurements of tCho in combination with clinicopathological criteria could predict non-pCR with a high AUC. Furthermore, tCho quantification for prediction of pCR was more sensitive for TN tumors. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2018;48:982-993.
Collapse
Affiliation(s)
| | - Patrick Flamen
- Nuclear Department, Institute Jules Bordet, Brussels, Belgium
| | | | - Thierry Metens
- Radiology Department, Erasme University Hospital, Brussels, Belgium
| | - Shih-Li Chao
- Radiology Department, Institute Jules Bordet, Brussels, Belgium
| | - Marie Chintinne
- Pathology Department, Institute Jules Bordet, Brussels, Belgium
| | - Marc Lemort
- Radiology Department, Institute Jules Bordet, Brussels, Belgium
| |
Collapse
|
28
|
Assländer J, Cloos MA, Knoll F, Sodickson DK, Hennig J, Lattanzi R. Low rank alternating direction method of multipliers reconstruction for MR fingerprinting. Magn Reson Med 2018; 79:83-96. [PMID: 28261851 PMCID: PMC5585028 DOI: 10.1002/mrm.26639] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 01/19/2017] [Accepted: 01/22/2017] [Indexed: 12/13/2022]
Abstract
PURPOSE The proposed reconstruction framework addresses the reconstruction accuracy, noise propagation and computation time for magnetic resonance fingerprinting. METHODS Based on a singular value decomposition of the signal evolution, magnetic resonance fingerprinting is formulated as a low rank (LR) inverse problem in which one image is reconstructed for each singular value under consideration. This LR approximation of the signal evolution reduces the computational burden by reducing the number of Fourier transformations. Also, the LR approximation improves the conditioning of the problem, which is further improved by extending the LR inverse problem to an augmented Lagrangian that is solved by the alternating direction method of multipliers. The root mean square error and the noise propagation are analyzed in simulations. For verification, in vivo examples are provided. RESULTS The proposed LR alternating direction method of multipliers approach shows a reduced root mean square error compared to the original fingerprinting reconstruction, to a LR approximation alone and to an alternating direction method of multipliers approach without a LR approximation. Incorporating sensitivity encoding allows for further artifact reduction. CONCLUSION The proposed reconstruction provides robust convergence, reduced computational burden and improved image quality compared to other magnetic resonance fingerprinting reconstruction approaches evaluated in this study. Magn Reson Med 79:83-96, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Jakob Assländer
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
- Center for Advanced Imaging Innovation and Research (CAIR), Department of Radiology, New York University School of Medicine, New York, NY, USA
- Dept. of Radiology, Medical Physics, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Martijn A Cloos
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
- Center for Advanced Imaging Innovation and Research (CAIR), Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Florian Knoll
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
- Center for Advanced Imaging Innovation and Research (CAIR), Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Daniel K Sodickson
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
- Center for Advanced Imaging Innovation and Research (CAIR), Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Jürgen Hennig
- Dept. of Radiology, Medical Physics, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Riccardo Lattanzi
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
- Center for Advanced Imaging Innovation and Research (CAIR), Department of Radiology, New York University School of Medicine, New York, NY, USA
| |
Collapse
|
29
|
Abstract
The direct delivery of drugs and other agents into tissue (in contrast to systemic administration) has been used in clinical trials for brain cancer, neurodegenerative diseases and peripheral tumors. However, continuing evidence suggests that clinical efficacy depends on adequate delivery to a target. Inadequate delivery may have doomed otherwise effective drugs, through failure to distinguish drug inefficacy from poor distribution at the target. Conventional pretreatment clinical images of the patient fail to reveal the complexity and diversity of drug transport pathways in tissue. We discuss the richness of these pathways and argue that development and patient treatment can be sped up and improved by: using quantitative as well as 'real-time' imaging; customized simulations using data from that imaging; and device designs that optimize the drug-device combination.
Collapse
|
30
|
Benveniste H, Lee H, Ding F, Sun Q, Al-Bizri E, Makaryus R, Probst S, Nedergaard M, Stein EA, Lu H. Anesthesia with Dexmedetomidine and Low-dose Isoflurane Increases Solute Transport via the Glymphatic Pathway in Rat Brain When Compared with High-dose Isoflurane. Anesthesiology 2017; 127:976-988. [PMID: 28938276 PMCID: PMC5685871 DOI: 10.1097/aln.0000000000001888] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND The glymphatic pathway transports cerebrospinal fluid through the brain, thereby facilitating waste removal. A unique aspect of this pathway is that its function depends on the state of consciousness of the brain and is associated with norepinephrine activity. A current view is that all anesthetics will increase glymphatic transport by inducing unconsciousness. This view implies that the effect of anesthetics on glymphatic transport should be independent of their mechanism of action, as long as they induce unconsciousness. We tested this hypothesis by comparing the supplementary effect of dexmedetomidine, which lowers norepinephrine, with isoflurane only, which does not. METHODS Female rats were anesthetized with either isoflurane (N = 8) or dexmedetomidine plus low-dose isoflurane (N = 8). Physiologic parameters were recorded continuously. Glymphatic transport was quantified by contrast-enhanced magnetic resonance imaging. Cerebrospinal fluid and gray and white matter volumes were quantified from T1 maps, and blood vessel diameters were extracted from time-of-flight magnetic resonance angiograms. Electroencephalograms were recorded in separate groups of rats. RESULTS Glymphatic transport was enhanced by 32% in rats anesthetized with dexmedetomidine plus low-dose isoflurane when compared with isoflurane. In the hippocampus, glymphatic clearance was sixfold more efficient during dexmedetomidine plus low-dose isoflurane anesthesia when compared with isoflurane. The respiratory and blood gas status was comparable in rats anesthetized with the two different anesthesia regimens. In the dexmedetomidine plus low-dose isoflurane rats, spindle oscillations (9 to 15 Hz) could be observed but not in isoflurane anesthetized rats. CONCLUSIONS We propose that anesthetics affect the glymphatic pathway transport not simply by inducing unconsciousness but also by additional mechanisms, one of which is the repression of norepinephrine release.
Collapse
Affiliation(s)
- Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT 06520 USA
| | - Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT 06520 USA
| | - Fengfei Ding
- Center for Translational Neuromedicine, University of Rochester, NY 14604, USA
| | - Qian Sun
- Center for Translational Neuromedicine, University of Rochester, NY 14604, USA
| | - Ehab Al-Bizri
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY 11794, USA
| | - Rany Makaryus
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY 11794, USA
| | - Stephen Probst
- Department of Anesthesiology, Stony Brook Medicine, Stony Brook, NY 11794, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester, NY 14604, USA
| | - Elliot A. Stein
- National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD 21224, USA
| | - Hanbing Lu
- National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD 21224, USA
| |
Collapse
|
31
|
Wang Y, Chen Y, Wu D, Wang Y, Sethi SK, Yang G, Xie H, Xia S, Haacke EM. STrategically Acquired Gradient Echo (STAGE) imaging, part II: Correcting for RF inhomogeneities in estimating T1 and proton density. Magn Reson Imaging 2017; 46:140-150. [PMID: 29061370 DOI: 10.1016/j.mri.2017.10.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 10/16/2017] [Accepted: 10/18/2017] [Indexed: 11/19/2022]
Abstract
PURPOSE To develop a method for mapping the B1 transmit (B1t) and B1 receive (B1r) fields from two gradient echo datasets each with a different flip angle and from these two images obtain accurate T1 and proton density (PD) maps of the brain. METHODS A strategically acquired gradient echo (STAGE) data set is collected using two flip angles each with multiple echoes. The B1t field extraction was based on forcing cortical gray matter and white matter to have specific T1 values and fitting the resulting B1t field to a quadratic function. The B1r field extraction was based on synthesizing isointense images despite there being two or three tissue types present in the brain. This method was tested on 10 healthy volunteers and 20 stroke patients from data acquired at 3.0Tesla. RESULTS With the knowledge of the B1t and B1r fields, the uniformity of tissue T1 and PD maps was considerably improved. T1 values were measured for both the midbrain and basal ganglia and found to be in good agreement with the literature. DISCUSSION AND CONCLUSIONS STAGE provides a practical way to assess the B1t and the B1r fields which can then be used to correct for spatial variations in the images.
Collapse
Affiliation(s)
- Yu Wang
- Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China
| | - Yongsheng Chen
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China; The MRI Institute for Biomedical Research, Detroit, MI, USA; Department of Radiology, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Dongmei Wu
- Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China
| | - Ying Wang
- Department of Biomedical Engineering, Wayne State University, Detroit, MI 48201, USA
| | - Sean K Sethi
- The MRI Institute for Biomedical Research, Detroit, MI, USA; Magnetic Resonance Innovations, Inc., Detroit, MI 48202, USA
| | - Guang Yang
- Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China
| | - Haibin Xie
- Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China
| | - Shuang Xia
- Tianjin First Central Hospital, Tianjin, China
| | - E Mark Haacke
- Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China; Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China; The MRI Institute for Biomedical Research, Detroit, MI, USA; Department of Radiology, School of Medicine, Wayne State University, Detroit, MI, USA; Department of Biomedical Engineering, Wayne State University, Detroit, MI 48201, USA; Magnetic Resonance Innovations, Inc., Detroit, MI 48202, USA.
| |
Collapse
|
32
|
Chao SL, Metens T, Lemort M. TumourMetrics: a comprehensive clinical solution for the standardization of DCE-MRI analysis in research and routine use. Quant Imaging Med Surg 2017; 7:496-510. [PMID: 29184762 DOI: 10.21037/qims.2017.09.02] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background A reliable analysis methodology is needed to provide valuable imaging biomarkers for clinical trials, with particular regards to dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) application using pharmacokinetic (PK) model analysis. In order to address this scientific challenge, we provided a comprehensive analysis solution that could overcome the impediments to clinical research and routine use. Methods TumourMetrics has been designed to meet the Quantitative Imaging Biomarkers Alliance (QIBA) v.1.0 profile. The quality performance was assessed using the QIBA test data and our customizable numeric phantom. The analysis workflow is made customizable to facilitate standardization of optimized protocol across centers. Results Our quantification workflow estimated the PK model parameters accurately. The method is robust, almost fully automatic and allows a direct integration of the results into the diagnostic workflow. Conclusions The analysis is easy-to-use and accessible for routine implementation of DCE-MRI into clinical practice.
Collapse
Affiliation(s)
- Shih-Li Chao
- Department of Radiology, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
| | - Thierry Metens
- Department of Radiology, Hôpital Erasme CUB, Ecole Polytechnique & Faculté de Médecine Université Libre de Bruxelles, Brussels, Belgium
| | - Marc Lemort
- Department of Radiology, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
| |
Collapse
|
33
|
Lee H, Mortensen K, Sanggaard S, Koch P, Brunner H, Quistorff B, Nedergaard M, Benveniste H. Quantitative Gd-DOTA uptake from cerebrospinal fluid into rat brain using 3D VFA-SPGR at 9.4T. Magn Reson Med 2017. [PMID: 28627037 DOI: 10.1002/mrm.26779] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE We propose a quantitative technique to assess solute uptake into the brain parenchyma based on dynamic contrast-enhanced MRI (DCE-MRI). With this approach, a small molecular weight paramagnetic contrast agent (Gd-DOTA) is infused in the cerebral spinal fluid (CSF) and whole brain gadolinium concentration maps are derived. METHODS We implemented a 3D variable flip angle spoiled gradient echo (VFA-SPGR) longitudinal relaxation time (T1) technique, the accuracy of which was cross-validated by way of inversion recovery rapid acquisition with relaxation enhancement (IR-RARE) using phantoms. Normal Wistar rats underwent Gd-DOTA infusion into CSF via the cisterna magna and continuous MRI for approximately 130 min using T1-weighted imaging. Dynamic Gd-DOTA concentration maps were calculated and parenchymal uptake was estimated. RESULTS In the phantom study, T1 discrepancies between the VFA-SPGR and IR-RARE sequences were approximately 6% with a transmit coil inhomogeneity correction. In the in vivo study, contrast transport profiles indicated maximal parenchymal retention of approximately 19% relative to the total amount delivered into the cisterna magna. CONCLUSION Imaging strategies for accurate 3D contrast concentration mapping at 9.4T were developed and whole brain dynamic concentration maps were derived to study solute transport via the glymphatic system. The newly developed approach will enable future quantitative studies of the glymphatic system in health and disease states. Magn Reson Med 79:1568-1578, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Kristian Mortensen
- Section for Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Simon Sanggaard
- Section for Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Palle Koch
- Section for Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hans Brunner
- Section for Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bjørn Quistorff
- Department of Biomedical Sciences, University of Copenhagen, The Panum Institute, Copenhagen, Denmark
| | - Maiken Nedergaard
- Section for Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Division of Glia Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, New York, USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut, USA
| |
Collapse
|
34
|
Shcherbakova Y, van den Berg CAT, Moonen CTW, Bartels LW. PLANET: An ellipse fitting approach for simultaneous T 1 and T 2 mapping using phase-cycled balanced steady-state free precession. Magn Reson Med 2017; 79:711-722. [PMID: 28543430 PMCID: PMC5811804 DOI: 10.1002/mrm.26717] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 03/23/2017] [Accepted: 03/26/2017] [Indexed: 11/09/2022]
Abstract
Purpose To demonstrate the feasibility of a novel, ellipse fitting approach, named PLANET, for simultaneous estimation of relaxation times T1 and T2 from a single 3D phase‐cycled balanced steady‐state free precession (bSSFP) sequence. Methods A method is presented in which the elliptical signal model is used to describe the phase‐cycled bSSFP steady‐state signal. The fitting of the model to the acquired data is reformulated into a linear convex problem, which is solved directly by a linear least squares method, specific to ellipses. Subsequently, the relaxation times T1 and T2, the banding free magnitude, and the off‐resonance are calculated from the fitting results. Results Maps of T1 and T2, as well as an off‐resonance and a banding free magnitude can be simultaneously, quickly, and robustly estimated from a single 3D phase‐cycled bSSFP sequence. The feasibility of the method was demonstrated in a phantom and in the brain of healthy volunteers on a clinical MR scanner. The results were in good agreement for the phantom, but a systematic underestimation of T1 was observed in the brain. Conclusion The presented method allows for accurate mapping of relaxation times and off‐resonance, and for the reconstruction of banding free magnitude images at realistic signal‐to‐noise ratios. Magn Reson Med 79:711–722, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
Collapse
Affiliation(s)
- Yulia Shcherbakova
- Center for Image Sciences, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Cornelis A T van den Berg
- Department of Radiotherapy, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Chrit T W Moonen
- Center for Image Sciences, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Lambertus W Bartels
- Center for Image Sciences, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| |
Collapse
|
35
|
Lee Y, Callaghan MF, Nagy Z. Analysis of the Precision of Variable Flip Angle T1 Mapping with Emphasis on the Noise Propagated from RF Transmit Field Maps. Front Neurosci 2017; 11:106. [PMID: 28337119 PMCID: PMC5343565 DOI: 10.3389/fnins.2017.00106] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 02/20/2017] [Indexed: 11/13/2022] Open
Abstract
In magnetic resonance imaging, precise measurements of longitudinal relaxation time (T1) is crucial to acquire useful information that is applicable to numerous clinical and neuroscience applications. In this work, we investigated the precision of T1 relaxation time as measured using the variable flip angle method with emphasis on the noise propagated from radiofrequency transmit field ([Formula: see text]) measurements. The analytical solution for T1 precision was derived by standard error propagation methods incorporating the noise from the three input sources: two spoiled gradient echo (SPGR) images and a [Formula: see text] map. Repeated in vivo experiments were performed to estimate the total variance in T1 maps and we compared these experimentally obtained values with the theoretical predictions to validate the established theoretical framework. Both the analytical and experimental results showed that variance in the [Formula: see text] map propagated comparable noise levels into the T1 maps as either of the two SPGR images. Improving precision of the [Formula: see text] measurements significantly reduced the variance in the estimated T1 map. The variance estimated from the repeatedly measured in vivoT1 maps agreed well with the theoretically-calculated variance in T1 estimates, thus validating the analytical framework for realistic in vivo experiments. We concluded that for T1 mapping experiments, the error propagated from the [Formula: see text] map must be considered. Optimizing the SPGR signals while neglecting to improve the precision of the [Formula: see text] map may result in grossly overestimating the precision of the estimated T1 values.
Collapse
Affiliation(s)
- Yoojin Lee
- Laboratory for Social and Neural Systems Research, University of ZürichZürich, Switzerland; Department of Information Technology and Electrical Engineering, Institute of Biomedical Engineering, ETH ZürichZürich, Switzerland
| | - Martina F Callaghan
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London London, UK
| | - Zoltan Nagy
- Laboratory for Social and Neural Systems Research, University of ZürichZürich, Switzerland; Department of Information Technology and Electrical Engineering, Institute of Biomedical Engineering, ETH ZürichZürich, Switzerland
| |
Collapse
|
36
|
Nataraj G, Nielsen JF, Fessler JA. Optimizing MR Scan Design for Model-Based ${T}_{1}$ , ${T}_{2}$ Estimation From Steady-State Sequences. IEEE TRANSACTIONS ON MEDICAL IMAGING 2017; 36:467-477. [PMID: 27893386 PMCID: PMC5378699 DOI: 10.1109/tmi.2016.2614967] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Rapid, reliable quantification of MR relaxation parameters T1 and T2 is desirable for many clinical applications. Steady-state sequences such as Spoiled Gradient-Recalled Echo (SPGR) and Dual-Echo Steady-State (DESS) are fast and well-suited for relaxometry because the signals they produce are quite sensitive to T1 and T2 variation. However, T1, T2 estimation with these sequences typically requires multiple scans with varied sets of acquisition parameters. This paper describes a systematic framework for selecting scan types (e.g., combinations of SPGR and DESS scans) and optimizing their respective parameters (e.g., flip angles and repetition times). The method is based on a Cramér-Rao Bound (CRB)-inspired min-max optimization that finds scan parameter combinations that robustly enable precise object parameter estimation. We apply this technique to optimize combinations of SPGR and DESS scans for T1, T2 relaxometry in white matter (WM) and grey matter (GM) regions of the human brain at 3T field strength. Phantom accuracy experiments show that SPGR/DESS scan combinations are in excellent agreement with reference measurements. Phantom precision experiments show that trends in T1,T2 pooled sample standard deviations reflect CRB-based predictions. In vivo experiments show that in WM and GM, T1 and T2 estimates from a pair of optimized DESS scans exhibit precision (but not necessarily accuracy) comparable to that of optimized combinations of SPGR and DESS scans. To our knowledge, T1 maps from DESS acquisitions alone are new. This example application illustrates that scan optimization may help reveal new parameter mapping techniques from combinations of established pulse sequences.
Collapse
|
37
|
Correction of T1 Effects in Calculation of Relative Recirculation in Ischemic Stroke Patients. J Med Biol Eng 2016. [DOI: 10.1007/s40846-016-0167-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
38
|
Kallehauge JF, Sourbron S, Irving B, Tanderup K, Schnabel JA, Chappell MA. Comparison of linear and nonlinear implementation of the compartmental tissue uptake model for dynamic contrast-enhanced MRI. Magn Reson Med 2016; 77:2414-2423. [PMID: 27605429 PMCID: PMC5484345 DOI: 10.1002/mrm.26324] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/10/2016] [Accepted: 06/08/2016] [Indexed: 12/14/2022]
Abstract
Purpose Fitting tracer kinetic models using linear methods is much faster than using their nonlinear counterparts, although this comes often at the expense of reduced accuracy and precision. The aim of this study was to derive and compare the performance of the linear compartmental tissue uptake (CTU) model with its nonlinear version with respect to their percentage error and precision. Theory and Methods The linear and nonlinear CTU models were initially compared using simulations with varying noise and temporal sampling. Subsequently, the clinical applicability of the linear model was demonstrated on 14 patients with locally advanced cervical cancer examined with dynamic contrast‐enhanced magnetic resonance imaging. Results Simulations revealed equal percentage error and precision when noise was within clinical achievable ranges (contrast‐to‐noise ratio >10). The linear method was significantly faster than the nonlinear method, with a minimum speedup of around 230 across all tested sampling rates. Clinical analysis revealed that parameters estimated using the linear and nonlinear CTU model were highly correlated (ρ ≥ 0.95). Conclusion The linear CTU model is computationally more efficient and more stable against temporal downsampling, whereas the nonlinear method is more robust to variations in noise. The two methods may be used interchangeably within clinical achievable ranges of temporal sampling and noise. Magn Reson Med 77:2414–2423, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Collapse
Affiliation(s)
- Jesper F Kallehauge
- Institute of Biomedical Engineering, Department of Engineering Science University of Oxford, Oxford, United Kingdom
| | - Steven Sourbron
- Division of Biomedical Imaging, University of Leeds, Leeds, United Kingdom
| | - Benjamin Irving
- Institute of Biomedical Engineering, Department of Engineering Science University of Oxford, Oxford, United Kingdom
| | - Kari Tanderup
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Julia A Schnabel
- Division of Imaging Science and Biomedical Engineering, King's College London, London, United Kingdom
| | - Michael A Chappell
- Institute of Biomedical Engineering, Department of Engineering Science University of Oxford, Oxford, United Kingdom
| |
Collapse
|
39
|
Zhang JL, Conlin CC, Carlston K, Xie L, Kim D, Morrell G, Morton K, Lee VS. Optimization of saturation-recovery dynamic contrast-enhanced MRI acquisition protocol: monte carlo simulation approach demonstrated with gadolinium MR renography. NMR IN BIOMEDICINE 2016; 29:969-77. [PMID: 27200499 PMCID: PMC5206992 DOI: 10.1002/nbm.3553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 03/13/2016] [Accepted: 04/11/2016] [Indexed: 05/18/2023]
Abstract
Dynamic contrast-enhanced (DCE) MRI is widely used for the measurement of tissue perfusion and to assess organ function. MR renography, which is acquired using a DCE sequence, can measure renal perfusion, filtration and concentrating ability. Optimization of the DCE acquisition protocol is important for the minimization of the error propagation from the acquired signals to the estimated parameters, thus improving the precision of the parameters. Critical to the optimization of contrast-enhanced T1 -weighted protocols is the balance of the T1 -shortening effect across the range of gadolinium (Gd) contrast concentration in the tissue of interest. In this study, we demonstrate a Monte Carlo simulation approach for the optimization of DCE MRI, in which a saturation-recovery T1 -weighted gradient echo sequence is simulated and the impact of injected dose (D) and time delay (TD, for saturation recovery) is tested. The results show that high D and/or high TD cause saturation of the peak arterial signals and lead to an overestimation of renal plasma flow (RPF) and glomerular filtration rate (GFR). However, the use of low TD (e.g. 100 ms) and low D leads to similar errors in RPF and GFR, because of the Rician bias in the pre-contrast arterial signals. Our patient study including 22 human subjects compared TD values of 100 and 300 ms after the injection of 4 mL of Gd contrast for MR renography. At TD = 100 ms, we computed an RPF value of 157.2 ± 51.7 mL/min and a GFR of 33.3 ± 11.6 mL/min. These results were all significantly higher than the parameter estimates at TD = 300 ms: RPF = 143.4 ± 48.8 mL/min (p = 0.0006) and GFR = 30.2 ± 11.5 mL/min (p = 0.0015). In conclusion, appropriate optimization of the DCE MRI protocol using simulation can effectively improve the precision and, potentially, the accuracy of the measured parameters. Copyright © 2016 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Jeff L. Zhang
- Correspondence to: J. L. Zhang, University of Utah School of Medicine, Department of Radiology, 729 Arapeend Dr., Salt Lake City, UT 84108, USA.
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Aryal MP, Chenevert TL, Cao Y. Impact of uncertainty in longitudinal T1 measurements on quantification of dynamic contrast-enhanced MRI. NMR IN BIOMEDICINE 2016; 29:411-419. [PMID: 27358934 PMCID: PMC4929815 DOI: 10.1002/nbm.3482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The objective of this study was to assess the uncertainty in T1 measurement, by estimating the repeatability coefficient (RC) from two repeated scans, in normal appearing brain tissues employing two different T1 mapping methods. All brain MRI scans were performed on a 3 T MR scanner in 10 patients who had low grade/benign tumors and partial brain radiation therapy (RT) without chemotherapy, at pre-RT, 3 weeks into RT, end RT (6 weeks) and 11, 33, and 85 weeks after RT. T1-weighted images were acquired using (1) a spoiled gradient echo sequence with two flip angles (2FA: 5° and 15°) and (2) a progressive saturation recovery sequence (pSR) with five different TR values (100-2000 ms). Manually drawn volumes of interest (VOIs) included left and right normal putamen and thalamus in gray matter, and frontal and parietal white matter, which were distant from tumors and received a total of accumulated radiation doses less than 5 Gy at 3 weeks. No significant changes or even trends in mean T1 from pre-RT to 3 weeks into RT in these VOIs (p ≥ 0.11, Wilcoxon sign test) allowed us to calculate the repeatability statistics of between-subject means of squares, within-subject means of squares, F-score, and RC. The 2FA method produced RCs in the range of (9.7-11.7)% in gray matter and (12.2-14.5)% in white matter; while the pSR method led to RCs ranging from 10.9 to 17.9% in gray matter and 7.5 to 10.3% in white matter. The overall mean (±SD) RCs produced by the two methods, 12.0 (±1.6)% for 2FA and 12.0 (±3.8)% for pSR, were not significantly different (p = 0.97). A similar repeatability in T1 measurement produced by the time efficient 2FA method compared with the time consuming pSR method demonstrates that the 2FA method is desirable to integrate into dynamic contrast-enhanced MRI for rapid acquisition.
Collapse
Affiliation(s)
- Madhava P. Aryal
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | | | - Yue Cao
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
41
|
Lewis CM, Hurley SA, Meyerand ME, Koay CG. Data-driven optimized flip angle selection for T1 estimation from spoiled gradient echo acquisitions. Magn Reson Med 2015; 76:792-802. [PMID: 26361720 DOI: 10.1002/mrm.25920] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/12/2015] [Accepted: 08/14/2015] [Indexed: 11/06/2022]
Abstract
PURPOSE Define criteria for selection of optimal flip angle sets for T1 estimation and evaluate effects on T1 mapping. THEORY AND METHODS Flip angle sets for spoiled gradient echo-based T1 mapping were selected by minimizing T1 estimate variance weighted by the joint density of M0 and T1 in an initial acquisition. The effect of optimized flip angle selection on T1 estimate error was measured using simulations and experimental data in the human and rat brain. RESULTS For two-point acquisitions, optimized angle sets were similar to those proposed by other groups and, therefore, performed similarly. For multipoint acquisitions, optimal angle sets for T1 mapping in the brain consisted of a repetition of two angles. Implementation of optimal angles reduced T1 estimate variance by 30-40% compared with a multipoint acquisition using a range of angles. Performance of the optimal angle set was equivalent to that of a repetition of the two-angle set selected using criteria proposed by other researchers. CONCLUSION Repetition of two carefully selected flip angles notably improves the precision of resulting T1 estimates compared with acquisitions using a range of flip angles. This work provides a flexible and widely applicable optimization method of particular use for those who repeatedly perform T1 estimation. Magn Reson Med 76:792-802, 2016. © 2015 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Christina M Lewis
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Samuel A Hurley
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - M Elizabeth Meyerand
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Cheng Guan Koay
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| |
Collapse
|
42
|
Drisis S, Metens T, Ignatiadis M, Stathopoulos K, Chao SL, Lemort M. Quantitative DCE-MRI for prediction of pathological complete response following neoadjuvant treatment for locally advanced breast cancer: the impact of breast cancer subtypes on the diagnostic accuracy. Eur Radiol 2015; 26:1474-84. [DOI: 10.1007/s00330-015-3948-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/27/2015] [Accepted: 07/27/2015] [Indexed: 10/23/2022]
|
43
|
Heule R, Ganter C, Bieri O. Variable flip angle T1 mapping in the human brain with reduced T2 sensitivity using fast radiofrequency-spoiled gradient echo imaging. Magn Reson Med 2015; 75:1413-22. [PMID: 25980525 DOI: 10.1002/mrm.25668] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 01/08/2015] [Accepted: 02/02/2015] [Indexed: 11/06/2022]
Abstract
PURPOSE Variable flip angle (VFA) T1 quantification using three-dimensional (3D) radiofrequency (RF) spoiled gradient echo imaging offers the acquisition of whole-brain T1 maps in clinically acceptable times. However, conventional VFA T1 relaxometry is biased by incomplete spoiling (i.e., residual T2 dependency). A new postprocessing approach is proposed to overcome this T2-related bias. METHODS T1 is quantified from the signal ratio of two spoiled gradient echo (SPGR) images acquired at different flip angles using an analytical solution for the RF-spoiled steady-state signal in combination with a global T2 guess. T1 accuracy is evaluated from simulations and in vivo 3D SPGR imaging of the human brain at 3 Tesla. RESULTS The simulations demonstrated that the sensitivity of VFA T1 mapping to T2 can considerably be reduced using a global T2 guess. The method proved to deliver reliable and accurate T1 values in vivo for white and gray matter in good agreement with inversion recovery reference measurements. CONCLUSION Based on a global T2 estimate, the accuracy of VFA T1 relaxometry in the human brain can substantially be improved compared with conventional approaches which rely on the generally wrong assumption of ideal spoiling.
Collapse
Affiliation(s)
- Rahel Heule
- Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Basel, Switzerland
| | - Carl Ganter
- Department of Radiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Oliver Bieri
- Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Basel, Switzerland
| |
Collapse
|
44
|
Lescher S, Jurcoane A, Veit A, Bähr O, Deichmann R, Hattingen E. Quantitative T1 and T2 mapping in recurrent glioblastomas under bevacizumab: earlier detection of tumor progression compared to conventional MRI. Neuroradiology 2014; 57:11-20. [DOI: 10.1007/s00234-014-1445-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 09/25/2014] [Indexed: 11/28/2022]
|
45
|
Rauscher I, Bender B, Grözinger G, Luz O, Pohmann R, Erb M, Schick F, Martirosian P. Assessment of T1, T1ρ, and T2 values of the ulnocarpal disc in healthy subjects at 3 tesla. Magn Reson Imaging 2014; 32:1085-90. [PMID: 24960365 DOI: 10.1016/j.mri.2014.05.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 04/03/2014] [Accepted: 05/26/2014] [Indexed: 11/17/2022]
Abstract
OBJECTIVE The purpose of this study was to implement clinically feasible imaging techniques for determination of T1, T1ρ, and T2 values of the ulnocarpal disc and to assess those values in a cohort of asymptomatic subjects at 3 tesla. Resulting values were compared between different age groups, since former histological findings of the ulnocarpal disc indicated frequent early degenerative changes of this tissue starting in the third decade of life, even in asymptomatic subjects. MATERIALS AND METHODS Twenty-seven healthy subjects were included in this study. T1 measurements were performed using 3D spoiled gradient-echo (GRE) sequence with variable flip angle. A series of T1ρ and T2-weighted images was acquired by a 3D GRE sequence after suitable magnetization preparation. T1,T1ρ, and T2 maps of the ulnocarpal disc were calculated pixel-wise. Representative mean values from extended regions were analysed. RESULTS Mean T1 values of the ulnocarpal disc ranged from 722 ms in a 39 year-old subject to 1264 ms in a 65 year-old subject, T1ρ ranged from 9.2 ms (26 year-old subject) to 25.9 ms (65 year-old subject). Calculated T2 values showed a large range from 4.1 ms to 22.3 ms. T1ρ and T1 values tended to increase with age (p<0.05), whereas T2 did not. CONCLUSIONS MR relaxometry of the ulnocarpal disc is feasible, and T1,T1ρ, and T2 values show modest variance in asymptomatic subjects. The potential of relaxation mapping to reveal relevant structural changes in patients has to be investigated in further studies.
Collapse
Affiliation(s)
- Isabel Rauscher
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University Tübingen, Tübingen, Germany
| | - Benjamin Bender
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University Tübingen, Tübingen, Germany; Department of Diagnostic and Interventional Neuroradiology, Eberhard-Karls University Tübingen, Tübingen, Germany
| | - Gerd Grözinger
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University Tübingen, Tübingen, Germany
| | - Oliver Luz
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University Tübingen, Tübingen, Germany
| | - Rolf Pohmann
- Max Planck Institute for Biological Cybernetics, Magnetic Resonance Center, Tübingen, Germany
| | - Michael Erb
- Department of Biomedical Magnetic Resonance, Eberhard-Karls University Tübingen, Tübingen, Germany
| | - Fritz Schick
- Section on Experimental Radiology, Eberhard-Karls University Tübingen, Tübingen, Germany
| | - Petros Martirosian
- Section on Experimental Radiology, Eberhard-Karls University Tübingen, Tübingen, Germany.
| |
Collapse
|
46
|
Fast water concentration mapping to normalize (1)H MR spectroscopic imaging. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2014; 28:87-100. [PMID: 24908199 DOI: 10.1007/s10334-014-0451-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 05/12/2014] [Accepted: 05/12/2014] [Indexed: 10/25/2022]
Abstract
OBJECT To propose a fast and robust acquisition and post-processing pipeline that is time-compatible with clinical explorations to obtain a proton density (ρ) map used as a reference for metabolic map normalization. This allows inter-subject and inter-group comparisons of magnetic resonance spectroscopic imaging (MRSI) data and longitudinal follow-up for single subjects. MATERIALS AND METHODS A multi-echo T 2 (*) mapping sequence, the XEP sequence for B 1 (+) -mapping and Driven Equilibrium Single Pulse Observation of T 1-an optimized variable flip angle method for T 1 mapping used for both B 1 (-) -mapping and M 0 calculation-were used to determine correction factors leading to quantitative water proton density maps at 3T. Normalized metabolite maps were obtained on a phantom and nine healthy volunteers. To show the potential use of this technique at the individual level, we also explored one patient with low-grade glioma. RESULTS Accurate ρ maps were obtained both on phantom and volunteers. After signal normalization with the generated ρ maps, metabolic concentrations determined by the present method differed from theory by <7 % in the phantom and were in agreement with data from the literature for the healthy controls. Using these normalized metabolic values, it was possible to demonstrate in the patient with brain glioma, metabolic abnormalities in normalized N-acetyl aspartate, choline and creatine levels; illustrating the potential for direct use of this technique in clinical studies. CONCLUSION The proposed combination of sequences provides a robust ρ map that can be used to normalize metabolic maps in clinical MRSI studies.
Collapse
|
47
|
In vivo performance of a microfabricated catheter for intraparenchymal delivery. J Neurosci Methods 2014; 229:76-83. [PMID: 24747536 DOI: 10.1016/j.jneumeth.2014.03.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 03/27/2014] [Accepted: 03/28/2014] [Indexed: 11/22/2022]
Abstract
BACKGROUND Convection-enhanced delivery (CED) is currently the only effective clinical technique to deliver biological therapeutic agents that would otherwise not cross the blood-brain barrier. Despite the promise of CED, several technical problems have limited its effectiveness. NEW METHOD Brain infusions into a large mammal (pig) were performed with a catheter that was fabricated using micro-electro-mechanical systems (MEMS) technology (Olbricht et al., 2010). The performance of the catheter was evaluated for infusions at increasing infusion rates. Magnetic resonance (MR) images were acquired in real time to examine the distribution of infused tracers in the parenchyma. RESULTS Both backflow and the distribution of CED of infusates into a variety of cytoarchitectures in porcine brain were quantified. Concentration profiles were determined for several MR contrast reagents as well as a fluorescent dye that are the sizes of small molecules, therapeutic proteins and an adeno-associated virus (AAV). The reagents can serve as surrogates for assessing the convective distribution of active molecules. Infusion rates up to 20μL/min were attained without evidence of backflow along the catheter. COMPARISON WITH EXISTING METHODS The device performed well in terms of both backflow and infusion, superior to that of many studies reported in the literature on other catheters. All infused molecules had comparable ratios of distribution to infusion volumes. CONCLUSIONS The catheter described in this report appears able to target tissue structures with precision, deliver therapeutics at high infusion rates, and resist backflow that can compromise the efficacy of CED therapy. The technology allows development of "smart" catheters for future applications.
Collapse
|
48
|
Dieringer MA, Deimling M, Santoro D, Wuerfel J, Madai VI, Sobesky J, von Knobelsdorff-Brenkenhoff F, Schulz-Menger J, Niendorf T. Rapid parametric mapping of the longitudinal relaxation time T1 using two-dimensional variable flip angle magnetic resonance imaging at 1.5 Tesla, 3 Tesla, and 7 Tesla. PLoS One 2014; 9:e91318. [PMID: 24621588 PMCID: PMC3951399 DOI: 10.1371/journal.pone.0091318] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 02/08/2014] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Visual but subjective reading of longitudinal relaxation time (T1) weighted magnetic resonance images is commonly used for the detection of brain pathologies. For this non-quantitative measure, diagnostic quality depends on hardware configuration, imaging parameters, radio frequency transmission field (B1+) uniformity, as well as observer experience. Parametric quantification of the tissue T1 relaxation parameter offsets the propensity for these effects, but is typically time consuming. For this reason, this study examines the feasibility of rapid 2D T1 quantification using a variable flip angles (VFA) approach at magnetic field strengths of 1.5 Tesla, 3 Tesla, and 7 Tesla. These efforts include validation in phantom experiments and application for brain T1 mapping. METHODS T1 quantification included simulations of the Bloch equations to correct for slice profile imperfections, and a correction for B1+. Fast gradient echo acquisitions were conducted using three adjusted flip angles for the proposed T1 quantification approach that was benchmarked against slice profile uncorrected 2D VFA and an inversion-recovery spin-echo based reference method. Brain T1 mapping was performed in six healthy subjects, one multiple sclerosis patient, and one stroke patient. RESULTS Phantom experiments showed a mean T1 estimation error of (-63±1.5)% for slice profile uncorrected 2D VFA and (0.2±1.4)% for the proposed approach compared to the reference method. Scan time for single slice T1 mapping including B1+ mapping could be reduced to 5 seconds using an in-plane resolution of (2×2) mm2, which equals a scan time reduction of more than 99% compared to the reference method. CONCLUSION Our results demonstrate that rapid 2D T1 quantification using a variable flip angle approach is feasible at 1.5T/3T/7T. It represents a valuable alternative for rapid T1 mapping due to the gain in speed versus conventional approaches. This progress may serve to enhance the capabilities of parametric MR based lesion detection and brain tissue characterization.
Collapse
Affiliation(s)
- Matthias A. Dieringer
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, HELIOS Clinics Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
- * E-mail:
| | - Michael Deimling
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- Siemens Healthcare, Erlangen, Germany
| | - Davide Santoro
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Jens Wuerfel
- Institute of Neuroradiology, University Medicine Göttingen, Göttingen, Germany
- NeuroCure Clinical Research Center, Charité University Medicine Berlin, Berlin, Germany
| | - Vince I. Madai
- Clinic for Neurology & Center for Stroke Research Berlin, Charité Medical Faculty Berlin, Berlin, Germany
| | - Jan Sobesky
- Clinic for Neurology & Center for Stroke Research Berlin, Charité Medical Faculty Berlin, Berlin, Germany
| | - Florian von Knobelsdorff-Brenkenhoff
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, HELIOS Clinics Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
| | - Jeanette Schulz-Menger
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, HELIOS Clinics Berlin Buch, Department of Cardiology and Nephrology, Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| |
Collapse
|
49
|
Zhang T, Pauly JM, Levesque IR. Accelerating parameter mapping with a locally low rank constraint. Magn Reson Med 2014; 73:655-61. [PMID: 24500817 DOI: 10.1002/mrm.25161] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 09/09/2013] [Accepted: 09/20/2013] [Indexed: 11/06/2022]
Abstract
PURPOSE To accelerate MR parameter mapping using a locally low rank (LLR) constraint, and the combination of parallel imaging and the LLR constraint. THEORY AND METHODS An LLR method is developed for MR parameter mapping and compared with a globally low rank method in a multiecho spin-echo T2 mapping experiment. For acquisition with coil arrays, a combined LLR and parallel imaging method is proposed. The proposed method is evaluated in a variable flip angle T1 mapping experiment and compared with the LLR method and parallel imaging alone. RESULTS In the multiecho spin-echo T2 mapping experiment, the LLR method is more accurate than the globally low rank method for acceleration factors 2 and 3, especially for tissues with high T2 values. Variable flip angle T1 mapping is achieved by acquiring datasets with 10 flip angles, each dataset accelerated by a factor of 6, and reconstructed by the proposed method with a small normalized root mean square error of 0.025. CONCLUSIONS The LLR method is likely superior to the globally low rank method for MR parameter mapping. The proposed combined LLR and parallel imaging method has better performance than the two methods alone, especially with highly accelerated acquisition.
Collapse
Affiliation(s)
- Tao Zhang
- Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA
| | | | | |
Collapse
|
50
|
Osting S, Bennett A, Power S, Wackett J, Hurley SA, Alexander AL, Agbandje-Mckena M, Burger C. Differential effects of two MRI contrast agents on the integrity and distribution of rAAV2 and rAAV5 in the rat striatum. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2014; 1:4. [PMID: 26015943 PMCID: PMC4365861 DOI: 10.1038/mtm.2013.4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 10/30/2013] [Indexed: 11/10/2022]
Abstract
Intraoperative magnetic resonance imaging (MRI) has been proposed as a method to optimize intracerebral targeting and for tracking infusate distribution in gene therapy trials for nervous system disorders. We thus investigated possible effects of two MRI contrast agents, gadoteridol (Gd) and galbumin (Gab), on the distribution and levels of transgene expression in the rat striatum and their effect on integrity and stability of recombinant adeno-associated virus (rAAV) particles. MRI studies showed that contrast agent distribution did not predict rAAV distribution. However, green fluorescent protein (GFP) immunoreactivity revealed an increase in distribution of rAAV5-GFP, but not rAAV2-GFP, in the presence of Gd when compared with viral vector injected alone. In contrast, Gab increased the distribution of rAAV2-GFP not rAAV5-GFP. These observations pointed to a direct effect of infused contrast agent on the rAAV particles. Negative-stain electron microscopy (EM), DNAase treatment, and differential scanning calorimetry (DSC) were used to monitor rAAV2 and rAAV5 particle integrity and stability following contrast agent incubation. EMs of rAAV2-GFP and rAAV5-GFP particles pretreated with Gd appear morphologically similar to the untreated sample; however, Gab treatment resulted in surface morphology changes and aggregation. A compromise of particle integrity was suggested by sensitivity of the packaged genome to DNAase treatment following Gab incubation but not Gd for both vectors. However, neither agent significantly affected particle stability when analyzed by DSC. An increase in T m was observed for AAV2 in lactated Ringer's buffer. These results thus highlight potential interactions between MRI contrast agents and AAV that might affect vector distribution and stability, as well as the stabilizing effect of lactated Ringer's solution on AAV2.
Collapse
Affiliation(s)
- Sue Osting
- Department of Neurology, University of Wisconsin , Madison, Wisconsin, USA
| | - Antonette Bennett
- Department of Biochemistry, University of Florida , Gainesville, Florida, USA
| | - Shelby Power
- Department of Neurology, University of Wisconsin , Madison, Wisconsin, USA
| | - Jordan Wackett
- Department of Neurology, University of Wisconsin , Madison, Wisconsin, USA
| | - Samuel A Hurley
- Department of Medical Physics, University of Wisconsin , Madison, Wisconsin, USA
| | - Andrew L Alexander
- Department of Medical Physics, University of Wisconsin , Madison, Wisconsin, USA ; Department of Psychiatry, University of Wisconsin , Madison, Wisconsin, USA ; Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin , Madison, Wisconsin, USA
| | | | - Corinna Burger
- Department of Neurology, University of Wisconsin , Madison, Wisconsin, USA
| |
Collapse
|