101
|
Liu R, Zhang H, Niu W, Lai C, Ding Q, Chen W, Liang S, Zhou J, Wu D, Zhang Y. Improved chemical exchange saturation transfer imaging with real-time frequency drift correction. Magn Reson Med 2019; 81:2915-2923. [PMID: 30697813 DOI: 10.1002/mrm.27663] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 12/10/2018] [Accepted: 12/28/2018] [Indexed: 01/24/2023]
Abstract
PURPOSE To investigate the effects of frequency drift on chemical exchange saturation transfer (CEST) imaging at 3T, and to propose a new sequence for correcting artifacts attributed to B0 drift in real time. THEORY AND METHODS A frequency-stabilized CEST (FS-CEST) imaging sequence was proposed by adding a frequency stabilization module to the conventional non-frequency-stabilized CEST (NFS-CEST) sequence, which consisted of a small tip angle radiofrequency excitation pulse and readout of three non-phase-encoded k-space lines. Experiments were performed on an egg white phantom and 26 human subjects on a heavy-duty clinical scanner, in order to compare the difference of FS-CEST and NFS-CEST sequences for generating the z-spectrum, magnetization transfer ratio asymmetry (MTRasym ) spectrum, and amide proton transfer weighted (APTw) image. RESULTS The B0 drift in CEST imaging, if not corrected, would cause APTw images and MTRasym spectra from both the phantom and volunteers to be either significantly higher or lower than the true values, depending on the status of the scanner. The FS-CEST sequence generated substantially more stable MTRasym spectra and APTw images than the conventional NFS-CEST sequence. Quantitatively, the compartmental-average APTw signals (mean ± standard deviation) from frontal white matter regions of all 26 human subjects were -0.32% ± 2.32% for the NFS-CEST sequence and -0.14% ± 0.37% for the FS-CEST sequence. CONCLUSIONS The proposed FS-CEST sequence provides an effective approach for B0 drift correction without additional scan time and should be adopted on heavy-duty MRI scanners.
Collapse
Affiliation(s)
- Ruibin Liu
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hongxi Zhang
- Department of Radiology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Weiming Niu
- Department of Radiology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Can Lai
- Department of Radiology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Qiuping Ding
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | | | - Sayuan Liang
- Clinical Research Board, Philips Research China, Shanghai, China
| | - Jinyuan Zhou
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Dan Wu
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Yi Zhang
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| |
Collapse
|
102
|
Sun H, Xin J, Zhou J, Lu Z, Guo Q. Applying Amide Proton Transfer MR Imaging to Hybrid Brain PET/MR: Concordance with Gadolinium Enhancement and Added Value to [ 18F]FDG PET. Mol Imaging Biol 2019; 20:473-481. [PMID: 29063304 DOI: 10.1007/s11307-017-1136-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE The purpose of this study is to evaluate the diagnostic concordance and metric correlations of amide proton transfer (APT) imaging with gadolinium-enhanced magnetic resonance imaging (MRI) and 2-deoxy-2-[18F-]fluoro-D-glucose ([18F]FDG) positron emission tomography (PET), using hybrid brain PET/MRI. PROCEDURES Twenty-one subjects underwent brain gadolinium-enhanced [18F]FDG PET/MRI prospectively. Imaging accuracy was compared between unenhanced MRI, MRI with enhancement, APT-weighted (APTW) images, and PET based on six diagnostic criteria. Among tumors, the McNemar test was further used for concordance assessment between gadolinium-enhanced imaging, APT imaging, and [18F]FDG PET. As well, the relation of metrics between APT imaging and PET was analyzed by the Pearson correlation analysis. RESULTS APT imaging and gadolinium-enhanced MRI showed superior and similar diagnostic accuracy. APTW signal intensity and gadolinium enhancement were concordant in 19 tumors (100 %), while high [18F]FDG avidity was shown in only 12 (63.2 %). For the metrics from APT imaging and PET, there was significant correlation for 13 hypermetabolic tumors (P < 0.05) and no correlation for the remaining six [18F]FDG-avid tumors. CONCLUSIONS APT imaging can be used to increase diagnostic accuracy with no need to administer gadolinium chelates. APT imaging may provide an added value to [18F]FDG PET in the evaluation of tumor metabolic activity during brain PET/MR studies.
Collapse
Affiliation(s)
- Hongzan Sun
- Department of Radiology, Shengjing Hospital of China Medical University, Sanhao Street No. 36, Heping District, Shenyang, 110004, Liaoning, People's Republic of China
| | - Jun Xin
- Department of Radiology, Shengjing Hospital of China Medical University, Sanhao Street No. 36, Heping District, Shenyang, 110004, Liaoning, People's Republic of China.
| | - Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University, 600 N. Wolfe Street, Park 336, Baltimore, MD, 21287, USA
| | - Zaiming Lu
- Department of Radiology, Shengjing Hospital of China Medical University, Sanhao Street No. 36, Heping District, Shenyang, 110004, Liaoning, People's Republic of China
| | - Qiyong Guo
- Department of Radiology, Shengjing Hospital of China Medical University, Sanhao Street No. 36, Heping District, Shenyang, 110004, Liaoning, People's Republic of China
| |
Collapse
|
103
|
Zhou J, Heo HY, Knutsson L, van Zijl PCM, Jiang S. APT-weighted MRI: Techniques, current neuro applications, and challenging issues. J Magn Reson Imaging 2019; 50:347-364. [PMID: 30663162 DOI: 10.1002/jmri.26645] [Citation(s) in RCA: 199] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/26/2018] [Accepted: 12/27/2018] [Indexed: 02/06/2023] Open
Abstract
Amide proton transfer-weighted (APTw) imaging is a molecular MRI technique that generates image contrast based predominantly on the amide protons in mobile cellular proteins and peptides that are endogenous in tissue. This technique, the most studied type of chemical exchange saturation transfer imaging, has been used successfully for imaging of protein content and pH, the latter being possible due to the strong dependence of the amide proton exchange rate on pH. In this article we briefly review the basic principles and recent technical advances of APTw imaging, which is showing promise clinically, especially for characterizing brain tumors and distinguishing recurrent tumor from treatment effects. Early applications of this approach to stroke, Alzheimer's disease, Parkinson's disease, multiple sclerosis, and traumatic brain injury are also illustrated. Finally, we outline the technical challenges for clinical APT-based imaging and discuss several controversies regarding the origin of APTw imaging signals in vivo. Level of Evidence: 3 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;50:347-364.
Collapse
Affiliation(s)
- Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Hye-Young Heo
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Linda Knutsson
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Peter C M van Zijl
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Shanshan Jiang
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| |
Collapse
|
104
|
Heo HY, Han Z, Jiang S, Schär M, van Zijl PCM, Zhou J. Quantifying amide proton exchange rate and concentration in chemical exchange saturation transfer imaging of the human brain. Neuroimage 2019; 189:202-213. [PMID: 30654175 DOI: 10.1016/j.neuroimage.2019.01.034] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 01/09/2019] [Accepted: 01/13/2019] [Indexed: 12/31/2022] Open
Abstract
Current chemical exchange saturation transfer (CEST) neuroimaging protocols typically acquire CEST-weighted images, and, as such, do not essentially provide quantitative proton-specific exchange rates (or brain pH) and concentrations. We developed a dictionary-free MR fingerprinting (MRF) technique to allow CEST parameter quantification with a reduced data set. This was accomplished by subgrouping proton exchange models (SPEM), taking amide proton transfer (APT) as an example, into two-pool (water and semisolid macromolecules) and three-pool (water, semisolid macromolecules, and amide protons) models. A variable radiofrequency saturation scheme was used to generate unique signal evolutions for different tissues, reflecting their CEST parameters. The proposed MRF-SPEM method was validated using Bloch-McConnell equation-based digital phantoms with known ground-truth, which showed that MRF-SPEM can achieve a high degree of accuracy and precision for absolute CEST parameter quantification and CEST phantoms. For in-vivo studies at 3 T, using the same model as in the simulations, synthetic Z-spectra were generated using rates and concentrations estimated from the MRF-SPEM reconstruction and compared with experimentally measured Z-spectra as the standard for optimization. The MRF-SPEM technique can provide rapid and quantitative human brain CEST mapping.
Collapse
Affiliation(s)
- Hye-Young Heo
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
| | - Zheng Han
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Shanshan Jiang
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Michael Schär
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Peter C M van Zijl
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| |
Collapse
|
105
|
Nishie A, Asayama Y, Ishigami K, Ushijima Y, Takayama Y, Okamoto D, Fujita N, Tsurumaru D, Togao O, Sagiyama K, Manabe T, Oki E, Kubo Y, Hida T, Hirahashi-Fujiwara M, Keupp J, Honda H. Amide proton transfer imaging to predict tumor response to neoadjuvant chemotherapy in locally advanced rectal cancer. J Gastroenterol Hepatol 2019; 34:140-146. [PMID: 29900583 DOI: 10.1111/jgh.14315] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/28/2018] [Accepted: 06/02/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIM The amount of proteins and peptides can be estimated with amide proton transfer (APT) imaging. Previous studies demonstrated the usefulness of APT imaging to predict tumor malignancy. We determined whether APT imaging can predict the tumor response to neoadjuvant chemotherapy (NAC) in patients with locally advanced rectal cancer (LARC). METHODS Seventeen patients with LARC who underwent a pretherapeutic magnetic resonance examination including APT imaging and NAC (at least two courses) were enrolled. The APT-weighted imaging (WI) signal intensity (SI) (%) was defined as magnetization transfer ratio asymmetry (MTRasym ) at the offset of 3.5 ppm. Each tumor was histologically evaluated for the degree of degeneration and necrosis and then classified as one of five histological Grades (0, none; 1a, less than 1/3; 1b, 1/3 to 2/3; 2, more than 2/3; 3, all). We compared the mean APTWI SIs of the tumors between the Grade 0/1a/1b (low-response group) and Grade 2/3 (high-response group) by Student's t-test. We used receiver operating characteristics curves to determine the diagnostic performance of the APTWI SI for predicting the tumor response. RESULTS The mean APTWI SI of the low-response group (n = 12; 3.05 ± 1.61%) was significantly higher than that of the high-response group (n = 5; 1.14 ± 1.13%) (P = 0.029). The area under the curve for predicting the tumor response using the APTWI SI was 0.87. When ≥2.75% was used as an indicator of low-response status, 75% sensitivity and 100% specificity of the APTWI SI were obtained. CONCLUSION Pretherapeutic APT imaging can predict the tumor response to NAC in patients with LARC.
Collapse
Affiliation(s)
- Akihiro Nishie
- Department of Clinical Radiology, Kyushu University, Fukuoka, Japan
| | - Yoshiki Asayama
- Department of Clinical Radiology, Kyushu University, Fukuoka, Japan
| | - Kousei Ishigami
- Department of Clinical Radiology, Kyushu University, Fukuoka, Japan
| | | | - Yukihisa Takayama
- Department of Radiology Informatics and Network, Kyushu University, Fukuoka, Japan
| | - Daisuke Okamoto
- Department of Clinical Radiology, Kyushu University, Fukuoka, Japan
| | - Nobuhiro Fujita
- Department of Clinical Radiology, Kyushu University, Fukuoka, Japan
| | | | - Osamu Togao
- Department of Clinical Radiology, Kyushu University, Fukuoka, Japan
| | - Koji Sagiyama
- Department of Clinical Radiology, Kyushu University, Fukuoka, Japan
| | - Tatsuya Manabe
- Department of Surgery and Oncology, Kyushu University, Fukuoka, Japan
| | - Eiji Oki
- Department of Surgery and Science, Kyushu University, Fukuoka, Japan
| | - Yuichiro Kubo
- Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomoyuki Hida
- Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Minako Hirahashi-Fujiwara
- Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | | | - Hiroshi Honda
- Department of Clinical Radiology, Kyushu University, Fukuoka, Japan
| |
Collapse
|
106
|
Windschuh J, Zaiss M, Ehses P, Lee JS, Jerschow A, Regatte RR. Assessment of frequency drift on CEST MRI and dynamic correction: application to gagCEST at 7 T. Magn Reson Med 2019; 81:573-582. [PMID: 29851141 PMCID: PMC6258338 DOI: 10.1002/mrm.27367] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 02/02/2023]
Abstract
PURPOSE To investigate the effect of a frequency drift of the static magnetic field on 3D CEST MRI based on glycosaminoglycans (GAGs) of articular cartilage at 7 T and to introduce a retrospective correction method that uses the phase images of the gradient-echo readout. METHODS Repeated gagCEST and B0 measurements were performed in a glucose model solution and in vivo in the knee joint of 3 healthy volunteers at 7 T. Phase images of the modified 3D rectangular spiral centric-reordered gradient-echo CEST sequence were used to quantify and compensate the apparent frequency drift in repeated gagCEST measurements. RESULTS The frequency drift of the MRI scanner strongly influences the gagCEST signal in the articular cartilage of the human knee joint. The gagCEST signal in the articular cartilage is changed by 0.18%/Hz while an average drift of 0.7 ± 0.2 Hz/minute was observed. The proposed correction method can be applied retrospectively without the need of additional measurements and provides improved comparability and reproducibility for gagCEST studies. This correction method may also be of interest for other applications of CEST MRI. CONCLUSION Prospective or retrospective correction of the frequency drift of the MRI scanner is essential for reproducible gagCEST measurements. The proposed retrospective correction method fulfills this requirement without the need of additional measurements.
Collapse
Affiliation(s)
- Johannes Windschuh
- New York University Langone Medical Center, Department of Radiology, Center for Biomedical Imaging, 660 First Avenue, New York, NY 10013, USA
| | - Moritz Zaiss
- Max Planck Institute for Biological Cybernetics, High-field Magnetic Resonance Center, Spemannstr. 41, 72076 Tübingen, Germany
| | - Philipp Ehses
- German Center for Neurodegenerative Diseases, Department of MR Physics, Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Jae-Seung Lee
- New York University Langone Medical Center, Department of Radiology, Center for Biomedical Imaging, 660 First Avenue, New York, NY 10013, USA
- New York University, Department of Chemistry, 100 Washington Square East, New York, NY 10003, USA
| | - Alexej Jerschow
- New York University, Department of Chemistry, 100 Washington Square East, New York, NY 10003, USA
| | - Ravinder R Regatte
- New York University Langone Medical Center, Department of Radiology, Center for Biomedical Imaging, 660 First Avenue, New York, NY 10013, USA
| |
Collapse
|
107
|
Qamar S, King AD, Ai QY, Law BKH, Chan JSM, Poon DMC, Tong M, Mo FKF, Chen W, Bhatia KS, Ahuja AT, Ma BBY, Yeung DKW, Wang YX, Yuan J. Amide proton transfer MRI detects early changes in nasopharyngeal carcinoma: providing a potential imaging marker for treatment response. Eur Arch Otorhinolaryngol 2018; 276:505-512. [DOI: 10.1007/s00405-018-5231-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 11/28/2018] [Indexed: 01/05/2023]
|
108
|
Simegn GL, Van der Kouwe AJW, Robertson FC, Meintjes EM, Alhamud A. Real-time simultaneous shim and motion measurement and correction in glycoCEST MRI using double volumetric navigators (DvNavs). Magn Reson Med 2018; 81:2600-2613. [PMID: 30506877 DOI: 10.1002/mrm.27597] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 10/13/2018] [Accepted: 10/16/2018] [Indexed: 11/11/2022]
Abstract
PURPOSE CEST MRI allows for indirect detection of molecules with exchangeable protons, measured as a reduction in water signal because of continuous transfer of saturated protons. CEST requires saturation pulses on the order of a second, as well as repeated acquisitions at different offset frequencies. The resulting extended scan time makes CEST susceptible to subject motion, which introduces field inhomogeneity, shifting offset frequencies and causing distortions in CEST spectra that resemble true CEST effects. This is a particular problem for molecules that resonate close to water, such as hydroxyl group in glycogen. To address this, a technique for real-time measurement and correction of motion and field inhomogeneity is proposed. METHODS A CEST sequence was modified to include double volumetric navigators (DvNavs) for real-time simultaneous motion and shim correction. Phantom tests were conducted to investigate the effects of motion and shim changes on CEST quantification and to validate the accuracy of DvNav motion and shim estimates. To evaluate DvNav shim and motion correction in vivo, acquisitions including 5 experimental conditions were performed in the calf muscle of 2 volunteers. RESULTS Phantom data show that DvNav-CEST accurately estimates frequency and linear gradient changes because of motion and corrects resulting image distortions. In addition, DvNav-CEST improves CEST quantification in vivo in the presence of motion. CONCLUSION The proposed technique allows for real-time simultaneous motion and shim correction with no additional scanning time, enabling accurate CEST quantification even in the presence of motion and field inhomogeneity.
Collapse
Affiliation(s)
- Gizeaddis L Simegn
- UCT Medical Imaging Research Unit, Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa
| | - Andre J W Van der Kouwe
- UCT Medical Imaging Research Unit, Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa.,Athinoula A. Martinos Center for Biomedical Imaging/MGH, Charlestown, Massachusetts.,Department of Radiology, Harvard Medical School, Boston, Massachusetts
| | - Frances C Robertson
- UCT Medical Imaging Research Unit, Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa.,Cape Universities Body Imaging Centre (CUBIC-UCT), Cape Town, South Africa
| | - Ernesta M Meintjes
- UCT Medical Imaging Research Unit, Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa.,Cape Universities Body Imaging Centre (CUBIC-UCT), Cape Town, South Africa
| | - Ali Alhamud
- UCT Medical Imaging Research Unit, Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa.,Cape Universities Body Imaging Centre (CUBIC-UCT), Cape Town, South Africa
| |
Collapse
|
109
|
Lin EC, Li H, Zu Z, Louie EA, Lankford CL, Dortch RD, Does MD, Gore JC, Gochberg DF. Chemical exchange rotation transfer (CERT) on human brain at 3 Tesla. Magn Reson Med 2018; 80:2609-2617. [PMID: 29802641 PMCID: PMC6252284 DOI: 10.1002/mrm.27365] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 03/23/2018] [Accepted: 04/24/2018] [Indexed: 12/14/2022]
Abstract
PURPOSE To test the ability of a novel pulse sequence applied in vivo at 3 Tesla to separate the contributions to the water signal from amide proton transfer (APT) and relayed nuclear Overhauser enhancement (rNOE) from background direct water saturation and semisolid magnetization transfer (MT). The lack of such signal source isolation has confounded conventional chemical exchange saturation transfer (CEST) imaging. METHODS We quantified APT and rNOE signals using a chemical exchange rotation transfer (CERT) metric, MTRdouble . A range of duty cycles and average irradiation powers were applied, and results were compared with conventional CEST analyses using asymmetry (MTRasym ) and extrapolated magnetization transfer (EMR). RESULTS Our results indicate that MTRdouble is more specific than MTRasym and, because it requires as few as 3 data points, is more rapid than methods requiring a complete Z-spectrum, such as EMR. In white matter, APT (1.5 ± 0.5%) and rNOE (2.1 ± 0.7%) were quantified by using MTRdouble with a 30% duty cycle and a 0.5-µT average power. In addition, our results suggest that MTRdouble is insensitive to B0 inhomogeneity, further magnifying its speed advantage over CEST metrics that require a separate B0 measurement. However, MTRdouble still has nontrivial sensitivity to B1 inhomogeneities. CONCLUSION We demonstrated that MTRdouble is an alternative metric to evaluate APT and rNOE, which is fast, robust to B0 inhomogeneity, and easy to process.
Collapse
Affiliation(s)
- Eugene C. Lin
- Vanderbilt University Institute of Imaging Science, Nashville, TN
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN
| | - Hua Li
- Vanderbilt University Institute of Imaging Science, Nashville, TN
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN
| | - Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Nashville, TN
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN
| | - Elizabeth A. Louie
- Vanderbilt University Institute of Imaging Science, Nashville, TN
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN
| | - Chris L. Lankford
- Vanderbilt University Institute of Imaging Science, Nashville, TN
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN
| | - Richard D. Dortch
- Vanderbilt University Institute of Imaging Science, Nashville, TN
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN
| | - Mark D. Does
- Vanderbilt University Institute of Imaging Science, Nashville, TN
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN
| | - John C. Gore
- Vanderbilt University Institute of Imaging Science, Nashville, TN
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN
- Deparment of Physics and Astronomy, Vanderbilt University, Nashville, TN
- Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Daniel F. Gochberg
- Vanderbilt University Institute of Imaging Science, Nashville, TN
- Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN
- Deparment of Physics and Astronomy, Vanderbilt University, Nashville, TN
| |
Collapse
|
110
|
Wu Y, Chen Y, Zhao Y, Yang S, Zhao J, Zhou J, Chen Z, Sun PZ, Zheng H. Direct radiofrequency saturation corrected amide proton transfer tumor MRI at 3T. Magn Reson Med 2018; 81:2710-2719. [DOI: 10.1002/mrm.27562] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/13/2018] [Accepted: 09/16/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Yin Wu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen Guangdong China
| | - Yinsheng Chen
- Department of Neurosurgery Cancer Center, Sun Yat‐Sen University Guangzhou Guangdong China
| | - Yiying Zhao
- Department of Neurosurgery Cancer Center, Sun Yat‐Sen University Guangzhou Guangdong China
| | - Shasha Yang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen Guangdong China
| | - Jing Zhao
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen Guangdong China
| | - Jian Zhou
- Department of Medical Imaging Cancer Center, Sun Yat‐Sen University Guangzhou Guangdong China
| | - Zhongping Chen
- Department of Neurosurgery Cancer Center, Sun Yat‐Sen University Guangzhou Guangdong China
| | - Phillip Zhe Sun
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology Massachusetts General Hospital and Harvard Medical School Charlestown Massachusetts
- Yerkes Imaging Center Yerkes National Primate Research Center, Emory University Atlanta Georgia
- Department of Radiology Emory University School of Medicine Atlanta Georgia
| | - Hairong Zheng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen Guangdong China
| |
Collapse
|
111
|
Roussel T, Rosenberg JT, Grant SC, Frydman L. Brain investigations of rodent disease models by chemical exchange saturation transfer at 21.1 T. NMR IN BIOMEDICINE 2018; 31:e3995. [PMID: 30052292 PMCID: PMC6419096 DOI: 10.1002/nbm.3995] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 06/08/2018] [Accepted: 06/09/2018] [Indexed: 05/08/2023]
Abstract
This study explores opportunities opened up by ultrahigh fields for in vivo saturation transfer brain magnetic resonance imaging experiments. Fast spin-echo images weighted by chemical exchange saturation transfer (CEST) effects were collected on Sprague-Dawley rats at 21.1 T, focusing on two neurological models. One involved a middle cerebral artery occlusion emulating ischemic stroke; the other involved xenografted glioma cells that were followed over the course of several days as they developed into brain tumors. A remarkably strong saturation-derived contrast was observed for the growing tumors when calculating magnetization transfer ratios at c. 3.8 ppm. This large contrast originated partially from an increase in the contribution of the amide CEST effect, but mostly from strong decreases in the Overhauser and magnetization transfer contributions to the upfield region, whose differential attenuations could be clearly discerned thanks to the ultrahigh field. The high spectral separation arising at 21.1 T also revealed numerous CEST signals usually overlapping at lower fields. Ischemic lesions were also investigated but, remarkably, magnetization and saturation transfer contrasts were nearly absent when computing transfer asymmetries using either high or low saturation power schemes. These behaviors were consistently observed at 24 hours post-occlusion, regardless of the data processing approach assayed. Considerations related to how various parameters defining these experiments depend on the magnetic field, primarily chemical shifts and T1 values, are discussed.
Collapse
Affiliation(s)
- Tangi Roussel
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | | | - Samuel C. Grant
- National High Magnetic Field Laboratory, Tallahassee, Florida
- Department of Chemical & Biomedical Engineering, FAMU-FSU College of Engineering, The Florida State University, Tallahassee, Florida
| | - Lucio Frydman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
- National High Magnetic Field Laboratory, Tallahassee, Florida
| |
Collapse
|
112
|
Jiang S, Eberhart CG, Lim M, Heo HY, Zhang Y, Blair L, Wen Z, Holdhoff M, Lin D, Huang P, Qin H, Quinones-Hinojosa A, Weingart JD, Barker PB, Pomper MG, Laterra J, van Zijl PCM, Blakeley JO, Zhou J. Identifying Recurrent Malignant Glioma after Treatment Using Amide Proton Transfer-Weighted MR Imaging: A Validation Study with Image-Guided Stereotactic Biopsy. Clin Cancer Res 2018; 25:552-561. [PMID: 30366937 DOI: 10.1158/1078-0432.ccr-18-1233] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 09/06/2018] [Accepted: 10/22/2018] [Indexed: 12/13/2022]
Abstract
PURPOSE To quantify the accuracy of amide proton transfer-weighted (APTw) MRI for identifying active glioma after treatment via radiographically guided stereotactic tissue validation.Experimental Design: Twenty-one patients who were referred for surgery for MRI features concerning for tumor progression versus treatment effect underwent preoperative APTw imaging. Stereotactic biopsy samples were taken from regions of interest with varying APTw signal intensities. The relationship between final clinical pathology and the histopathology of each of the 64 specimens was analyzed relative to APTw results. Analysis of confirmed recurrent tumor or treatment effect tissue was used to perform ROC analysis. RESULTS Eighteen of 21 patients had recurrent tumor, and 3 had treatment effect on clinical pathology. In 12 patients, there were multiple histopathologic assignments confirmed within the same tumor. Of the 64 total specimens, 20 specimens were active glioma, 27 mixed active and quiescent glioma, and 17 quiescent/no identifiable tumor. APTw signal intensity and histopathologic assignment, cellularity, and proliferation index had significant positive correlations (R = 0.651, 0.580, and 0.458, respectively; all P < 0.001). ROC analysis with a 1.79% APTw intensity cutoff differentiated active from nonactive tumor (AUC of 0.881) with 85.1% sensitivity and 94.1% specificity. Analysis of clinical pathology showed the mean APTw intensity for each patient had 94.4% sensitivity and 100% positive predictive value for identifying recurrent glioma at this cutoff. CONCLUSIONS APTw imaging hyperintensity may be a marker of active malignant glioma. It is able to distinguish between regions of heterogeneous abnormality on anatomic brain MRI with high sensitivity and specificity.
Collapse
Affiliation(s)
- Shanshan Jiang
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | | | - Michael Lim
- Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland
| | - Hye-Young Heo
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Yi Zhang
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Lindsay Blair
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland
| | - Zhibo Wen
- Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Matthias Holdhoff
- Department of Oncology, Johns Hopkins University, Baltimore, Maryland
| | - Doris Lin
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Peng Huang
- Department of Oncology, Johns Hopkins University, Baltimore, Maryland
| | - Huamin Qin
- Department of Pathology, Johns Hopkins University, Baltimore, Maryland
| | | | - Jon D Weingart
- Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland
| | - Peter B Barker
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Martin G Pomper
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - John Laterra
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland.,Department of Oncology, Johns Hopkins University, Baltimore, Maryland.,Department of Neuroscience, Johns Hopkins University, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Peter C M van Zijl
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | | | - Jinyuan Zhou
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland. .,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| |
Collapse
|
113
|
Kamimura K, Nakajo M, Yoneyama T, Takumi K, Kumagae Y, Fukukura Y, Yoshiura T. Amide proton transfer imaging of tumors: theory, clinical applications, pitfalls, and future directions. Jpn J Radiol 2018; 37:109-116. [DOI: 10.1007/s11604-018-0787-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 10/10/2018] [Indexed: 12/16/2022]
|
114
|
Nishie A, Takayama Y, Asayama Y, Ishigami K, Ushijima Y, Okamoto D, Fujita N, Tsurumaru D, Togao O, Manabe T, Oki E, Kubo Y, Hida T, Hirahashi-Fujiwara M, Keupp J, Honda H. Amide proton transfer imaging can predict tumor grade in rectal cancer. Magn Reson Imaging 2018; 51:96-103. [DOI: 10.1016/j.mri.2018.04.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 04/28/2018] [Accepted: 04/28/2018] [Indexed: 01/28/2023]
|
115
|
Yao J, Ruan D, Raymond C, Liau LM, Salamon N, Pope WB, Nghiemphu PL, Lai A, Cloughesy TF, Ellingson BM. Improving B 0 Correction for pH-Weighted Amine Proton Chemical Exchange Saturation Transfer (CEST) Imaging by Use of k-Means Clustering and Lorentzian Estimation. ACTA ACUST UNITED AC 2018; 4:123-137. [PMID: 30320212 PMCID: PMC6173788 DOI: 10.18383/j.tom.2018.00017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Amine chemical exchange saturation transfer (CEST) echoplanar imaging (EPI) provides unique pH and amino acid MRI contrast, enabling sensitive detection of altered microenvironment properties in various diseases. However, CEST contrast is sensitive to static magnetic field (B0) inhomogeneities. Here we propose 2 new B0 correction algorithms for use in correcting pH-weighted amine CEST EPI based on k-means clustering and Lorentzian fitting of CEST data: the iterative downsampling estimation using Lorentzian fitting and the 2-stage Lorentzian estimation with 4D polynomial fitting. Higher quality images of asymmetric magnetization transfer ratio (MTRasym) at 3.0 ppm could be obtained with the proposed algorithms than with the existing B0 correction methods. In particular, the proposed methods are shown to improve the intertissue consistency, interpatient consistency, and tumor region signal-to-noise ratio of MTRasym at 3.0 ppm images, with nonexcessive computation time.
Collapse
Affiliation(s)
- Jingwen Yao
- UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA.,Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA.,Department of Bioengineering, Henry Samueli School of Engineering and Applied Science, University of California Los Angeles, Los Angeles, CA
| | - Dan Ruan
- Departments of Radiation Oncology
| | - Catalina Raymond
- UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA.,Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Linda M Liau
- Neurosurgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Noriko Salamon
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | - Whitney B Pope
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| | | | | | | | - Benjamin M Ellingson
- UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA
| |
Collapse
|
116
|
Law BKH, King AD, Ai QY, Poon DMC, Chen W, Bhatia KS, Ahuja AT, Ma BB, Ka-Wai Yeung D, Fai Mo FK, Wang YX, Yuan J. Head and Neck Tumors: Amide Proton Transfer MRI. Radiology 2018; 288:782-790. [DOI: 10.1148/radiol.2018171528] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
117
|
Heo HY, Zhang Y, Jiang S, Zhou J. Influences of experimental parameters on chemical exchange saturation transfer (CEST) metrics of brain tumors using animal models at 4.7T. Magn Reson Med 2018; 81:316-330. [PMID: 30125383 DOI: 10.1002/mrm.27389] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 05/08/2018] [Accepted: 05/12/2018] [Indexed: 01/22/2023]
Abstract
PURPOSE To investigate the dependence of magnetization transfer ratio asymmetry at 3.5 ppm (MTRasym (3.5 ppm)), quantitative amide proton transfer (APT# ), and nuclear Overhauser enhancement (NOE# ) signals or contrasts on experimental imaging parameters. METHODS Modified Bloch equation-based simulations using 2-pool and 5-pool exchange models and in vivo rat brain tumor experiments at 4.7T were performed with varied RF saturation power levels, saturation lengths, and relaxation delays. The MTRasym (3.5 ppm), APT# , and NOE# contrasts between tumor and normal tissues were compared among different experimental parameters. RESULTS The MTRasym (3.5 ppm) image contrasts between tumor and normal tissues initially increased with the RF saturation length, and the maxima occurred at 1.6-2 s under relatively high RF saturation powers (>2.1 μT) and at a longer saturation length under relatively low RF saturation powers (<1.3 μT). The APT# contrasts also increased with the RF saturation length but peaked at longer RF saturation lengths relative to MTRasym (3.5 ppm). The NOE# contrasts were either positive or negative, depending on the experimental parameters applied. CONCLUSION Tumor MTRasym (3.5 ppm), APT# , and NOE# contrasts can be maximized at different saturation parameters. The maximum MTRasym (3.5 ppm) contrast can be obtained with a relatively longer RF saturation length (several seconds) at a relatively lower RF saturation power.
Collapse
Affiliation(s)
- Hye-Young Heo
- Divison of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Yi Zhang
- Divison of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland.,Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Shanshan Jiang
- Divison of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Jinyuan Zhou
- Divison of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| |
Collapse
|
118
|
Krikken E, Khlebnikov V, Zaiss M, Jibodh RA, van Diest PJ, Luijten PR, Klomp DWJ, van Laarhoven HWM, Wijnen JP. Amide chemical exchange saturation transfer at 7 T: a possible biomarker for detecting early response to neoadjuvant chemotherapy in breast cancer patients. Breast Cancer Res 2018; 20:51. [PMID: 29898745 PMCID: PMC6001024 DOI: 10.1186/s13058-018-0982-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 05/10/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The purpose of this work was to investigate noninvasive early detection of treatment response of breast cancer patients to neoadjuvant chemotherapy (NAC) using chemical exchange saturation transfer (CEST) measurements sensitive to amide proton transfer (APT) at 7 T. METHODS CEST images were acquired in 10 tumors of nine breast cancer patients treated with NAC. APT signals in the tumor, before and after the first cycle of NAC, were quantified using a three-pool Lorentzian fit of the z-spectra in the region of interest. The changes in APT were subsequently related to pathological response after surgery defined by the Miller-Payne system. RESULTS Significant differences (P < 0.05, unpaired Mann-Whitney test) were found in the APT signal before and after the first cycle of NAC in six out of 10 lesions, of which two showed a pathological complete response. Of the remaining four lesions, one showed a pathological complete response. No significant difference in changes of APT signal were found between the different pathological responses to NAC treatment (P > 0.05, Kruskal-Wallis test). CONCLUSIONS This preliminary study shows the feasibility of using APT CEST magnetic resonance imaging as a noninvasive biomarker to assess the effect of NAC in an early stage of NAC treatment of breast cancer patients. TRIAL REGISTRATION Registration number, NL49333.041.14/ NTR4980 . Registered on 16 October 2014.
Collapse
Affiliation(s)
- Erwin Krikken
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Vitaliy Khlebnikov
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Moritz Zaiss
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Rajni A. Jibodh
- Department of Medical Oncology, Academic Medical Centre Amsterdam, Amsterdam, The Netherlands
| | - Paul J. van Diest
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Peter R. Luijten
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W. J. Klomp
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Jannie P. Wijnen
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| |
Collapse
|
119
|
Lim H, Albatany M, Martínez-Santiesteban F, Bartha R, Scholl TJ. Longitudinal Measurements of Intra- and Extracellular pH Gradient in a Rat Model of Glioma. ACTA ACUST UNITED AC 2018; 4:46-54. [PMID: 30206544 PMCID: PMC6127347 DOI: 10.18383/j.tom.2018.00001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This study presents the first longitudinal measurement of the intracellular/extracellular pH gradient in a rat glioma model using noninvasive magnetic resonance imaging. The acid–base balance in the brain is tightly controlled by endogenous buffers. Tumors often express a positive pH gradient (pHi – pHe) compared with normal tissue that expresses a negative gradient. Alkaline pHi in tumor cells increases activity of several enzymes that drive cellular proliferation. In contrast, acidic pHe is established because of increased lactic acid production and subsequent active transport of protons out of the cell. pHi was mapped using chemical exchange saturation transfer, whereas regional pHe was determined using hyperpolarized 13C bicarbonate magnetic resonance spectroscopic imaging. pHi and pHe were measured at days 8, 12, and 15 postimplantation of C6 glioma cells into rat brains. Measurements were made in tumors and compared to brain tissue without tumor. Overall, average pH gradient in the tumor changed from −0.02 ± 0.12 to 0.10 ± 0.21 and then 0.19 ± 0.16. Conversely, the pH gradient of contralateral brain tissue changed from −0.45 ± 0.16 to −0.25 ± 0.21 and then −0.34 ± 0.25 (average pH ± 1 SD) Spatial heterogeneity of tumor pH gradient was apparent at later time points and may be useful to predict local areas of treatment resistance. Overall, the intracellular/extracellular pH gradients in this rat glioma model were noninvasively measured to a precision of ∼0.1 pH units at 3 time points. Because most therapeutic agents are weak acids or bases, a priori knowledge of the pH gradient may help guide choice of therapeutic agent for precision medicine.
Collapse
Affiliation(s)
- Heeseung Lim
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada
| | - Mohammed Albatany
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada
| | | | - Robert Bartha
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada.,Robarts Research Institute, University of Western Ontario, London, ON, Canada, and
| | - Timothy J Scholl
- Department of Medical Biophysics, University of Western Ontario, London, ON, Canada.,Robarts Research Institute, University of Western Ontario, London, ON, Canada, and.,Ontario Institute for Cancer Research, Toronto, ON, Canada
| |
Collapse
|
120
|
Luna A, Martín Noguerol T, Mata LA. Bases de la imagen funcional II: técnicas emergentes de resonancia magnética y nuevos métodos de análisis. RADIOLOGIA 2018. [DOI: 10.1016/j.rx.2018.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
121
|
Wech T, Köstler H. Robust motion correction in CEST imaging exploiting low-rank approximation of the z-spectrum. Magn Reson Med 2018; 80:1979-1988. [PMID: 29656510 DOI: 10.1002/mrm.27206] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 02/16/2018] [Accepted: 03/12/2018] [Indexed: 11/07/2022]
Abstract
PURPOSE To introduce and evaluate an image registration technique for robust quantification of CEST acquisitions corrupted by motion. METHODS The proposed iterative algorithm exploits a low-rank approximation of the z-spectrum (LRAZ), to gradually separate the contrast variation due to saturation at different off-resonance frequencies and accompanying motion. This registration method was first tested in a creatine CEST analysis of a phantom with simulated rigid motion. Subsequently, creatine CEST acquisitions in the human thigh during exercise were exemplarily corrected. RESULTS The z-spectrum obtained by applying LRAZ to the corrupted phantom series exhibited a normalized RMS error with respect to the noncorrupted gold standard series of less than 4%. The corresponding creatine map resulting from an asymmetry analysis of the registered data showed only little difference with regard to the noncorrupted determination, too. A comparable performance was observed exploiting LRAZ for the correction of nonrigid motion within the dynamic CEST acquisitions in skeletal muscles. While for the phantom simulations, high-quality registration was also possible by using a single reference image for the whole series and mutual information as similarity metric, this conventional approach resulted in inappropriate correction of the more complicated motion of the human thigh. CONCLUSION The newly introduced method allows for a robust registration of CEST image series, which are corrupted by rigid and nonrigid motion of the investigated organ. The technique therefore improves the diagnostic value in various applications of CEST.
Collapse
Affiliation(s)
- Tobias Wech
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany
- Comprehensive Heart Failure Center, University of Würzburg, Germany
| | - Herbert Köstler
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany
- Comprehensive Heart Failure Center, University of Würzburg, Germany
| |
Collapse
|
122
|
Zaiss M, Ehses P, Scheffler K. Snapshot-CEST: Optimizing spiral-centric-reordered gradient echo acquisition for fast and robust 3D CEST MRI at 9.4 T. NMR IN BIOMEDICINE 2018; 31:e3879. [PMID: 29372571 DOI: 10.1002/nbm.3879] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 06/07/2023]
Abstract
Gradient echo (GRE)-based acquisition provides a robust readout method for chemical exchange saturation transfer (CEST) at ultrahigh field (UHF). To develop a snapshot-CEST approach, the transient GRE signal and point spread function were investigated in detail, leading to optimized measurement parameters and reordering schemes for fast and robust volumetric CEST imaging. Simulation of the transient GRE signal was used to determine the optimal sequence parameters and the maximum feasible number of k-space lines. Point spread function analysis provided an insight into the induced k-space filtering and the performance of different rectangular reordering schemes in terms of blurring, signal-to-noise ratio (SNR) and relaxation dependence. Simulation results were confirmed in magnetic resonance imaging (MRI) measurements of healthy subjects. Minimal repetition time (TR) is beneficial for snapshot-GRE readout. At 9.4 T, for TR = 4 ms and optimal flip angle close to the Ernst angle, a maximum of 562 k-space lines can be acquired after a single presaturation, providing decent SNR with high image quality. For spiral-centric reordered k-space acquisition, the image quality can be further improved using a rectangular spiral reordering scheme adjusted to the field of view. Application of the derived snapshot-CEST sequence for fast imaging acquisition in the human brain at 9.4 T shows excellent image quality in amide and nuclear Overhauser enhancement (NOE), and enables guanidyl CEST detection. The proposed snapshot-CEST establishes a fast and robust volumetric CEST approach ready for the imaging of known and novel exchange-weighted contrasts at UHF.
Collapse
Affiliation(s)
- Moritz Zaiss
- High-field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Philipp Ehses
- High-field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Klaus Scheffler
- High-field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Department of Biomedical Magnetic Resonance, Eberhard-Karls University Tübingen, Tübingen, Germany
| |
Collapse
|
123
|
Takayama Y, Nishie A, Togao O, Asayama Y, Ishigami K, Ushijima Y, Okamoto D, Fujita N, Sonoda K, Hida T, Ohishi Y, Keupp J, Honda H. Amide Proton Transfer MR Imaging of Endometrioid Endometrial Adenocarcinoma: Association with Histologic Grade. Radiology 2018; 286:909-917. [DOI: 10.1148/radiol.2017170349] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Yukihisa Takayama
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Akihiro Nishie
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Osamu Togao
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Yoshiki Asayama
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Kousei Ishigami
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Yasuhiro Ushijima
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Daisuke Okamoto
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Nobuhiro Fujita
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Kenzo Sonoda
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Tomoyuki Hida
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Yoshihiro Ohishi
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Jochen Keupp
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| | - Hiroshi Honda
- From the Department of Radiology, Kitakyushu Municipal Medical Center, Kitakyushu, Japan (Y.T.); Departments of Clinical Radiology (Y.T., A.N., O.T., K.I., Y.U., D.O., N.F., H.H.), Advanced Imaging and Interventional Radiology (Y.A.), Gynecology and Obstetrics (K.S.), and Anatomic Pathology (T.H., Y.O.), Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka 812-8582, Japan; and Philips Research, Hamburg, Germany (J.K.)
| |
Collapse
|
124
|
Zhang S, Seiler S, Wang X, Madhuranthakam AJ, Keupp J, Knippa EE, Lenkinski RE, Vinogradov E. CEST-Dixon for human breast lesion characterization at 3 T: A preliminary study. Magn Reson Med 2018; 80:895-903. [PMID: 29322559 DOI: 10.1002/mrm.27079] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 11/24/2017] [Accepted: 12/17/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Shu Zhang
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Stephen Seiler
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Xinzeng Wang
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Ananth J Madhuranthakam
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | | | - Emily E Knippa
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Robert E Lenkinski
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Elena Vinogradov
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| |
Collapse
|
125
|
Zou T, Yu H, Jiang C, Wang X, Jiang S, Rui Q, Mei Y, Zhou J, Wen Z. Differentiating the histologic grades of gliomas preoperatively using amide proton transfer-weighted (APTW) and intravoxel incoherent motion MRI. NMR IN BIOMEDICINE 2018; 31:10.1002/nbm.3850. [PMID: 29098732 PMCID: PMC5757627 DOI: 10.1002/nbm.3850] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 09/15/2017] [Accepted: 09/25/2017] [Indexed: 06/07/2023]
Abstract
The purpose of this work was to investigate the diagnostic performance of amide proton transfer-weighted (APTW) and intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) in the preoperative grading of gliomas. Fifty-one patients with suspected gliomas were recruited and underwent a preoperative MRI examination that included APTW and IVIM sequences. All cases were confirmed by postsurgical histopathology. APTW signal intensity, true diffusion coefficient (D), perfusion fraction (f) and pseudo-diffusion coefficient (D*) were applied to assess the solid tumor component and contralateral normal-appearing white matter. The relative APTW signal intensity (rAPTW) was also used. Independent-sample and paired-sample t-tests were used to compare differences in MRI parameters between low-grade glioma (LGG) and high-grade glioma (HGG) groups. The diagnostic performance was assessed with the receiver operating characteristic curve. Twenty-six patients were pathologically diagnosed with LGG and 25 were diagnosed with HGG. APTW, rAPTW and f values were significantly higher (all p < 0.001), whereas D values were significantly lower (p < 0.001) in the HGG group than in the LGG group. There was no significant difference between D* values for the two groups. rAPTW had an area under the curve (AUC) of 0.957, with a sensitivity of 100% and a specificity of 84.6%, followed by APTW, f, D and D*. The combined use of APTW and IVIM showed the best diagnostic performance, with an AUC of 0.986. In conclusion, APTW and IVIM, as two promising supplementary sequences for routine MRI, could be valuable in differentiating LGGs from HGGs.
Collapse
Affiliation(s)
- Tianyu Zou
- Department of Radiology, Zhujiang Hospital, Southern Medical University, 253 Gongye Middle Avenue, Haizhu District, Guangzhou, Guangdong, 510282, P.R. China
| | - Hao Yu
- Department of Radiology, Zhujiang Hospital, Southern Medical University, 253 Gongye Middle Avenue, Haizhu District, Guangzhou, Guangdong, 510282, P.R. China
| | - Chunxiu Jiang
- Department of Radiology, Zhujiang Hospital, Southern Medical University, 253 Gongye Middle Avenue, Haizhu District, Guangzhou, Guangdong, 510282, P.R. China
| | - Xianlong Wang
- Department of Radiology, Zhujiang Hospital, Southern Medical University, 253 Gongye Middle Avenue, Haizhu District, Guangzhou, Guangdong, 510282, P.R. China
| | - Shanshan Jiang
- Department of Radiology, Zhujiang Hospital, Southern Medical University, 253 Gongye Middle Avenue, Haizhu District, Guangzhou, Guangdong, 510282, P.R. China
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, 600N. Wolfe Street, Baltimore, Maryland 21287, USA
| | - Qihong Rui
- Department of Radiology, Zhujiang Hospital, Southern Medical University, 253 Gongye Middle Avenue, Haizhu District, Guangzhou, Guangdong, 510282, P.R. China
| | - Yingjie Mei
- Philips Healthcare, Guangzhou, Guangdong, P.R. China
| | - Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, 600N. Wolfe Street, Baltimore, Maryland 21287, USA
| | - Zhibo Wen
- Department of Radiology, Zhujiang Hospital, Southern Medical University, 253 Gongye Middle Avenue, Haizhu District, Guangzhou, Guangdong, 510282, P.R. China
| |
Collapse
|
126
|
Discriminating MGMT promoter methylation status in patients with glioblastoma employing amide proton transfer-weighted MRI metrics. Eur Radiol 2017; 28:2115-2123. [PMID: 29234914 DOI: 10.1007/s00330-017-5182-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 10/30/2017] [Accepted: 11/06/2017] [Indexed: 02/07/2023]
Abstract
OBJECTIVES To explore the feasibility of using amide proton transfer-weighted (APTw) MRI metrics as surrogate biomarkers to identify the O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status in glioblastoma (GBM). METHODS Eighteen newly diagnosed GBM patients, who were previously scanned at 3T and had a confirmed MGMT methylation status, were retrospectively analysed. For each case, a histogram analysis in the tumour mass was performed to evaluate several quantitative APTw MRI metrics. The Mann-Whitney test was used to evaluate the difference in APTw parameters between MGMT methylated and unmethylated GBMs, and the receiver-operator-characteristic analysis was further used to assess diagnostic performance. RESULTS Ten GBMs were found to harbour a methylated MGMT promoter, and eight GBMs were unmethylated. The mean, variance, 50th percentile, 90th percentile and Width10-90 APTw values were significantly higher in the MGMT unmethylated GBMs than in the MGMT methylated GBMs, with areas under the receiver-operator-characteristic curves of 0.825, 0.837, 0.850, 0856 and 0.763, respectively, for the discrimination of MGMT promoter methylation status. CONCLUSIONS APTw signal metrics have the potential to serve as valuable imaging biomarkers for identifying MGMT methylation status in the GBM population. KEY POINTS • APTw-MRI is applied to predict MGMT promoter methylation status in GBMs. • GBMs with unmethylated MGMT promoter present higher APTw-MRI than methylated GBMs. • Multiple APTw histogram metrics can identify MGMT methylation status. • Mean APTw values showed the highest diagnostic accuracy (AUC = 0.825).
Collapse
|
127
|
Zhou IY, Wang E, Cheung JS, Lu D, Ji Y, Zhang X, Fulci G, Sun PZ. Direct saturation-corrected chemical exchange saturation transfer MRI of glioma: Simplified decoupling of amide proton transfer and nuclear overhauser effect contrasts. Magn Reson Med 2017; 78:2307-2314. [PMID: 29030880 PMCID: PMC5744877 DOI: 10.1002/mrm.26959] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 09/15/2017] [Accepted: 09/16/2017] [Indexed: 12/27/2022]
Abstract
PURPOSE Chemical exchange saturation transfer (CEST) MRI has shown promise in tissue characterization in diseases like stroke and tumor. However, in vivo CEST imaging such as amide proton transfer (APT) MRI is challenging because of concomitant factors such as direct water saturation, macromolecular magnetization transfer, and nuclear overhauser effect (NOE), which lead to a complex contrast in the commonly used asymmetry analysis (MTRasym). Here, we propose a direct saturation-corrected CEST (DISC-CEST) analysis for simplified decoupling and quantification of in vivo CEST effects. METHODS CEST MRI and relaxation measurements were carried out on a classical 2-pool creatine-gel CEST phantom and normal rat brains (N = 6) and a rat model of glioma (N = 8) at 4.7T. The proposed DISC-CEST quantification was carried out and compared with conventional MTRasym and the original three-offset method. RESULTS We demonstrated that the DISC-CEST contrast in the phantom had much stronger correlation with MTRasym than the three-offset method, which showed substantial underestimation. In normal rat brains, the DISC-CEST approach revealed significantly stronger APT effect in gray matter and higher NOE effect in white matter. Furthermore, the APT and NOE maps derived from DISC-CEST showed significantly higher APT effect in the tumors than contralateral normal tissue but no apparent difference in NOE. CONCLUSION The proposed DISC-CEST method, by correction of nonlinear direct water saturation effect, serves as a promising alternative to both the commonly used MTRasym and the simplistic three-offset analyses. It provides simple yet reliable in vivo CEST quantification such as APT and NOE mapping in brain tumor, which is promising for clinical translation. Magn Reson Med 78:2307-2314, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Iris Yuwen Zhou
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Enfeng Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
- Department of Radiology, 3 Affiliated Hospital, Zhengzhou University, Henan, China
| | - Jerry S Cheung
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Dongshuang Lu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Yang Ji
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Xiaoan Zhang
- Department of Radiology, 3 Affiliated Hospital, Zhengzhou University, Henan, China
| | - Giulia Fulci
- Molecular Neuro-oncology Laboratories, Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02124, USA
| | - Phillip Zhe Sun
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| |
Collapse
|
128
|
Cancer Metabolism and Tumor Heterogeneity: Imaging Perspectives Using MR Imaging and Spectroscopy. CONTRAST MEDIA & MOLECULAR IMAGING 2017; 2017:6053879. [PMID: 29114178 PMCID: PMC5654284 DOI: 10.1155/2017/6053879] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Revised: 07/31/2017] [Accepted: 08/27/2017] [Indexed: 12/26/2022]
Abstract
Cancer cells reprogram their metabolism to maintain viability via genetic mutations and epigenetic alterations, expressing overall dynamic heterogeneity. The complex relaxation mechanisms of nuclear spins provide unique and convertible tissue contrasts, making magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) pertinent imaging tools in both clinics and research. In this review, we summarized MR methods that visualize tumor characteristics and its metabolic phenotypes on an anatomical, microvascular, microstructural, microenvironmental, and metabolomics scale. The review will progress from the utilities of basic spin-relaxation contrasts in cancer imaging to more advanced imaging methods that measure tumor-distinctive parameters such as perfusion, water diffusion, magnetic susceptibility, oxygenation, acidosis, redox state, and cell death. Analytical methods to assess tumor heterogeneity are also reviewed in brief. Although the clinical utility of tumor heterogeneity from imaging is debatable, the quantification of tumor heterogeneity using functional and metabolic MR images with development of robust analytical methods and improved MR methods may offer more critical roles of tumor heterogeneity data in clinics. MRI/MRS can also provide insightful information on pharmacometabolomics, biomarker discovery, disease diagnosis and prognosis, and treatment response. With these future directions in mind, we anticipate the widespread utilization of these MR-based techniques in studying in vivo cancer biology to better address significant clinical needs.
Collapse
|
129
|
Systematic Evaluation of Amide Proton Chemical Exchange Saturation Transfer at 3 T: Effects of Protein Concentration, pH, and Acquisition Parameters. Invest Radiol 2017; 51:635-46. [PMID: 27272542 DOI: 10.1097/rli.0000000000000292] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE The goal of this work was to systematically evaluate the reproducibility of amide proton transfer chemical exchange saturation transfer (APT-CEST) at 3 T and its signal dependence on pH, protein concentration, and acquisition parameters. An in vitro system based on bovine serum albumin (BSA) was used, and its limitations were tested by comparing it to in vivo measurements. The contribution of small endogenous metabolites on the APT-CEST signal at 3 T was also investigated. In addition, the reliability of different z-spectrum interpolations as well as the use of only a few frequency offset data points instead of a whole z-spectrum were tested. MATERIALS AND METHODS We created both a BSA phantom at different concentrations and pH values and a metabolite phantom with different small molecules. Chemical exchange saturation transfer data were acquired using a 2-dimensional fast spoiled gradient-echo sequence with pulsed CEST preparation at different saturation durations and power levels. Healthy volunteer measurements were taken for comparison. Z-spectra were interpolated using a 24th-order polynomial (Poly), an eighth-order Fourier series (Fourier), and a smoothing Spline (sSpline) algorithm. To evaluate reduced data sets, only 6 to 14 frequency offsets of the z-spectrum were used and interpolated via a cubic Spline. Region of interest (ROI) evaluations were used to investigate the reproducibility of amide magnetization transfer ratio asymmetry [MTRasym(3.5 ppm)] and to analyze the MTRasym and z-spectra. RESULTS Interscan standard deviations of MTRasym(3.5 ppm) were always below 0.3%. MTRasym(3.5 ppm) increased when the BSA concentrations increased and decreased when the pH increased. The amine MTRasym signal of small molecules was very small compared with BSA and was only detectable using short saturation times and higher power levels. The MTRasym(3.5 ppm) between BSA concentration steps and between nearly all pH steps was significantly different for all 3 fitting methods. The Fourier and sSpline methods showed no statistically significant differences; however, the results for the Poly method were significantly higher at some concentrations and pH values. Using only few frequency offsets resulted in less significant differences compared with fitting the complete z-spectrum. In general, MTRasym(3.5 ppm) of gray matter, white matter, and ventricle ROIs from volunteer scans increased with an increase in saturation power and partially decreased with an increase in saturation duration. Intra-ROI covariances of MTRasym(3.5 ppm) revealed the highest variations for Poly, whereas using reduced spectral data resulted in an increased signal variation. CONCLUSIONS Amide proton transfer-CEST imaging is a highly reproducible method in which absolute signal differences of approximately 0.5% are detectable in principle. For in vivo applications, Fourier or sSpline interpolations of z-spectra are preferable. Using reduced data sets delivers similar results but with increased variation and therefore decreased (pH/concentration) differentiation capability. Differentiation capability increases with increases in the saturation duration and power level. The results from the in vitro BSA system cannot be directly transferred to the in vivo situation due to different chemical environments resulting in, for example, higher asymmetric macromolecular cMT effects in vivo. Amine signals from small molecules are unlikely to contribute to APT-CEST at 3 T (except for creatine); however, signals can be enhanced by using short saturation times and higher power levels.
Collapse
|
130
|
Zhang H, Wang W, Jiang S, Zhang Y, Heo HY, Wang X, Peng Y, Wang J, Zhou J. Amide proton transfer-weighted MRI detection of traumatic brain injury in rats. J Cereb Blood Flow Metab 2017; 37:3422-3432. [PMID: 28128026 PMCID: PMC5624391 DOI: 10.1177/0271678x17690165] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The purpose of this study was to explore the capability and uniqueness of amide proton transfer-weighted (APTw) imaging in the detection of primary and secondary injury after controlled cortical impact (CCI)-induced traumatic brain injury (TBI) in rats. Eleven adult rats had craniotomy plus CCI surgery under isoflurane anesthesia. Multi-parameter MRI data were acquired at 4.7 T, at eight time points (1, 6 h, and 1, 2, 3, 7, 14, and 28 days after TBI). At one and six hours post-injury, average APTw signal intensities decreased significantly in the impacted and peri-lesional areas due to tissue acidosis. A slightly high APTw signal was seen in the core lesion area with respect to the peri-lesional area, which was due to hemorrhage, as shown by T2*w. After the initial drop, the APTw signals dramatically increased in some peri-lesional areas at two and three days post-injury, likely due to the secondary inflammatory response. The use of APTw MRI has the potential to introduce a novel molecular neuroimaging approach for the simultaneous detection of ischemia, hemorrhage, and neuroinflammation in TBI.
Collapse
Affiliation(s)
- Hong Zhang
- 1 Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA.,2 Department of Radiology, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Wenzhu Wang
- 3 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA.,4 Department of Integrated Chinese and West Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shanshan Jiang
- 1 Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Yi Zhang
- 1 Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Hye-Young Heo
- 1 Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Xianlong Wang
- 1 Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Yun Peng
- 2 Department of Radiology, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Jian Wang
- 3 Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Jinyuan Zhou
- 1 Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| |
Collapse
|
131
|
Jones KM, Pollard AC, Pagel MD. Clinical applications of chemical exchange saturation transfer (CEST) MRI. J Magn Reson Imaging 2017; 47:11-27. [PMID: 28792646 DOI: 10.1002/jmri.25838] [Citation(s) in RCA: 184] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 05/30/2017] [Indexed: 02/06/2023] Open
Abstract
Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) has been developed and employed in multiple clinical imaging research centers worldwide. Selective radiofrequency (RF) saturation pulses with standard 2D and 3D MRI acquisition schemes are now routinely performed, and CEST MRI can produce semiquantitative results using magnetization transfer ratio asymmetry (MTRasym ) analysis while accounting for B0 inhomogeneity. Faster clinical CEST MRI acquisition methods and more quantitative acquisition and analysis routines are under development. Endogenous biomolecules with amide, amine, and hydroxyl groups have been detected during clinical CEST MRI studies, and exogenous CEST agents have also been administered to patients. These CEST MRI tools show promise for contributing to assessments of cerebral ischemia, neurological disorders, lymphedema, osteoarthritis, muscle physiology, and solid tumors. This review summarizes the salient features of clinical CEST MRI protocols and critically evaluates the utility of CEST MRI for these clinical imaging applications. LEVEL OF EVIDENCE 5 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:11-27.
Collapse
Affiliation(s)
- Kyle M Jones
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA
| | | | - Mark D Pagel
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA.,Department of Chemistry, Rice University, Houston, Texas, USA.,Department of Cancer Systems Imaging, MD Anderson Cancer Center, Houston, Texas, USA
| |
Collapse
|
132
|
Wang F, Takahashi K, Li H, Zu Z, Li K, Xu J, Harris RC, Takahashi T, Gore JC. Assessment of unilateral ureter obstruction with multi-parametric MRI. Magn Reson Med 2017; 79:2216-2227. [PMID: 28736875 DOI: 10.1002/mrm.26849] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/29/2017] [Accepted: 07/03/2017] [Indexed: 12/13/2022]
Abstract
PURPOSE Quantitative multi-parametric MRI (mpMRI) methods may allow the assessment of renal injury and function in a sensitive and objective manner. This study aimed to evaluate an array of MRI methods that exploit endogenous contrasts including relaxation rates, pool size ratio (PSR) derived from quantitative magnetization transfer (qMT), chemical exchange saturation transfer (CEST), nuclear Overhauser enhancement (NOE), and apparent diffusion coefficient (ADC) for their sensitivity and specificity in detecting abnormal features associated with kidney disease in a murine model of unilateral ureter obstruction (UUO). METHODS MRI scans were performed in anesthetized C57BL/6N mice 1, 3, or 6 days after UUO at 7T. Paraffin tissue sections were stained with Masson trichrome following MRI. RESULTS Compared to contralateral kidneys, the cortices of UUO kidneys showed decreases of relaxation rates R1 and R2 , PSR, NOE, and ADC. No significant changes in CEST effects were observed for the cortical region of UUO kidneys. The MRI parametric changes in renal cortex are related to tubular cell death, tubular atrophy, tubular dilation, urine retention, and interstitial fibrosis in the cortex of UUO kidneys. CONCLUSION Measurements of multiple MRI parameters provide comprehensive information about the molecular and cellular changes produced by UUO. Magn Reson Med 79:2216-2227, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Feng Wang
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Keiko Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University, Nashville, Tennessee, USA
| | - Hua Li
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Ke Li
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Junzhong Xu
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Raymond C Harris
- Division of Nephrology and Hypertension, Vanderbilt University, Nashville, Tennessee, USA
| | - Takamune Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University, Nashville, Tennessee, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| |
Collapse
|
133
|
Su C, Liu C, Zhao L, Jiang J, Zhang J, Li S, Zhu W, Wang J. Amide Proton Transfer Imaging Allows Detection of Glioma Grades and Tumor Proliferation: Comparison with Ki-67 Expression and Proton MR Spectroscopy Imaging. AJNR Am J Neuroradiol 2017; 38:1702-1709. [PMID: 28729292 DOI: 10.3174/ajnr.a5301] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 05/07/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Prognosis in glioma depends strongly on tumor grade and proliferation. In this prospective study of patients with untreated primary cerebral gliomas, we investigated whether amide proton transfer-weighted imaging could reveal tumor proliferation and reliably distinguish low-grade from high-grade gliomas compared with Ki-67 expression and proton MR spectroscopy imaging. MATERIALS AND METHODS This study included 42 patients with low-grade (n = 28) or high-grade (n = 14) glioma, all of whom underwent conventional MR imaging, proton MR spectroscopy imaging, and amide proton transfer-weighted imaging on the same 3T scanner within 2 weeks before surgery. We assessed metabolites of choline and N-acetylaspartate from proton MR spectroscopy imaging and the asymmetric magnetization transfer ratio at 3.5 ppm from amide proton transfer-weighted imaging and compared them with histopathologic grade and immunohistochemical expression of the proliferation marker Ki-67 in the resected specimens. RESULTS The asymmetric magnetization transfer ratio at 3.5 ppm values measured by different readers showed good concordance and were significantly higher in high-grade gliomas than in low-grade gliomas (3.61% ± 0.155 versus 2.64% ± 0.185, P = .0016), with sensitivity and specificity values of 92.9% and 71.4%, respectively, at a cutoff value of 2.93%. The asymmetric magnetization transfer ratio at 3.5 ppm values correlated with tumor grade (r = 0.506, P = .0006) and Ki-67 labeling index (r = 0.502, P = .002). For all patients, the asymmetric magnetization transfer ratio at 3.5 ppm correlated positively with choline (r = 0.43, P = .009) and choline/N-acetylaspartate ratio (r = 0.42, P = .01) and negatively with N-acetylaspartate (r = -0.455, P = .005). These correlations held for patients with low-grade gliomas versus those with high-grade gliomas, but the correlation coefficients were higher in high-grade gliomas (choline: r = 0.547, P = .053; N-acetylaspartate: r = -0.644, P = .017; choline/N-acetylaspartate: r = 0.583, P = .036). CONCLUSIONS The asymmetric magnetization transfer ratio at 3.5 ppm may serve as a potential biomarker not only for assessing proliferation, but also for predicting histopathologic grades in gliomas.
Collapse
Affiliation(s)
- C Su
- From the Department of Radiology (C.S., C.L., L.Z., J.J., J.Z., S.L., W.Z.), Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Hankou, Wuhan, People's Republic of China
| | - C Liu
- From the Department of Radiology (C.S., C.L., L.Z., J.J., J.Z., S.L., W.Z.), Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Hankou, Wuhan, People's Republic of China
| | - L Zhao
- From the Department of Radiology (C.S., C.L., L.Z., J.J., J.Z., S.L., W.Z.), Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Hankou, Wuhan, People's Republic of China
| | - J Jiang
- From the Department of Radiology (C.S., C.L., L.Z., J.J., J.Z., S.L., W.Z.), Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Hankou, Wuhan, People's Republic of China
| | - J Zhang
- From the Department of Radiology (C.S., C.L., L.Z., J.J., J.Z., S.L., W.Z.), Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Hankou, Wuhan, People's Republic of China
| | - S Li
- From the Department of Radiology (C.S., C.L., L.Z., J.J., J.Z., S.L., W.Z.), Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Hankou, Wuhan, People's Republic of China
| | - W Zhu
- From the Department of Radiology (C.S., C.L., L.Z., J.J., J.Z., S.L., W.Z.), Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Hankou, Wuhan, People's Republic of China
| | - J Wang
- Department of Radiation Physics (J.W.), The University of Texas MD Anderson Cancer Center, Houston, Texas
| |
Collapse
|
134
|
Jiang S, Zou T, Eberhart CG, Villalobos MAV, Heo HY, Zhang Y, Wang Y, Wang X, Yu H, Du Y, van Zijl PCM, Wen Z, Zhou J. Predicting IDH mutation status in grade II gliomas using amide proton transfer-weighted (APTw) MRI. Magn Reson Med 2017; 78:1100-1109. [PMID: 28714279 DOI: 10.1002/mrm.26820] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/31/2017] [Accepted: 06/11/2017] [Indexed: 12/24/2022]
Abstract
PURPOSE To assess the amide proton transfer-weighted (APTw) MRI features of isocitrate dehydrogenase (IDH)-wildtype and IDH-mutant grade II gliomas and to test the hypothesis that the APTw signal is a surrogate imaging marker for identifying IDH mutation status preoperatively. METHODS Twenty-seven patients with pathologically confirmed low-grade glioma, who were previously scanned at 3T, were retrospectively analyzed. The Mann-Whitney test was used to evaluate relationships between APTw intensities for IDH-mutant and IDH-wildtype groups, and receiver operator characteristic (ROC) analysis was used to assess the diagnostic performance of APTw. RESULTS Based on histopathology and molecular analysis, seven cases were diagnosed as IDH-wildtype grade II gliomas and 20 cases as IDH-mutant grade II gliomas. The maximum and minimum APTw values, based on multiple regions of interest, as well as the whole-tumor histogram-based mean and 50th percentile APTw values, were significantly higher in the IDH-wildtype gliomas than in the IDH-mutant groups. This corresponded to the areas under the ROC curves of 0.89, 0.76, 0.75, and 0.75, respectively, for the prediction of the IDH mutation status. CONCLUSION IDH-wildtype lesions typically were associated with relatively high APTw signal intensities as compared with IDH-mutant lesions. The APTw signal could be a valuable imaging biomarker by which to identify IDH1 mutation status in grade II gliomas. Magn Reson Med 78:1100-1109, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Shanshan Jiang
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China.,Department of Radiology, Futian Traditional Chinese Medicine Hospital, Shenzhen, Guangdong, China
| | - Tianyu Zou
- Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Charles G Eberhart
- Department of Pathology, Johns Hopkins University, Baltimore, Maryland, USA
| | | | - Hye-Young Heo
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Yi Zhang
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Yu Wang
- Department of Pathology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Xianlong Wang
- Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Hao Yu
- Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Yongxing Du
- Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Peter C M van Zijl
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Zhibo Wen
- Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| |
Collapse
|
135
|
Jiang S, Eberhart CG, Zhang Y, Heo HY, Wen Z, Blair L, Qin H, Lim M, Quinones-Hinojosa A, Weingart JD, Barker PB, Pomper MG, Laterra J, van Zijl PCM, Blakeley JO, Zhou J. Amide proton transfer-weighted magnetic resonance image-guided stereotactic biopsy in patients with newly diagnosed gliomas. Eur J Cancer 2017; 83:9-18. [PMID: 28704644 DOI: 10.1016/j.ejca.2017.06.009] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 05/31/2017] [Accepted: 06/11/2017] [Indexed: 01/03/2023]
Abstract
PURPOSE Pathological assessment using World Health Organization (WHO) criteria is the gold standard for diagnosis of gliomas. However, the accuracy of diagnosis is limited by tissue sampling, particularly for infiltrating, heterogeneous tumours. We assessed the accuracy of amide proton transfer-weighted (APTw) magnetic resonance imaging (MRI)-guided tissue sampling to identify regions of high-grade glioma via radiographic-histopathologic correlation in patients with newly suspected glioma. PATIENTS AND METHODS Twenty-four patients with previously undiagnosed gliomas underwent a volumetric APTw MRI prior to their first neurosurgical procedure. A total of 70 specimens were collected via APTw image-directed stereotactic biopsy. Cellularity, necrosis, proliferation and glioma WHO grade were analysed for all specimens and correlated with corresponding APTw signal intensities. RESULTS Thirty-three specimens displayed grade-II pathology, 14 grade-III, 15 grade-IV, and eight specimens revealed only peritumoural oedema. Multiple glioma grades were found within a single lesion in six patients. APTw signal intensities of the biopsied sites and the maximum APTw values across all biopsied sites in each patient were significantly higher for high-grade versus low-grade specimens. APTw signal intensities were significantly positively correlated with cellularity (R = 0.757) and proliferation (R = 0.538). Multiple linear regression analysis showed that tumour cellularity and proliferation index were the best predictors of APTw signal intensities. CONCLUSION APTw imaging identified tumour areas of higher cellularity and proliferation, allowing identification of high-grade regions within heterogeneous gliomas. APTw imaging can be readily translated for more widespread use and can assist diagnostic neurosurgical procedures by increasing the accuracy of tumour sampling in patients with infiltrating gliomas.
Collapse
Affiliation(s)
- Shanshan Jiang
- Department of Radiology, Johns Hopkins University, Baltimore, MD, USA; Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | | | - Yi Zhang
- Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Hye-Young Heo
- Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Zhibo Wen
- Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Lindsay Blair
- Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
| | - Huamin Qin
- Department of Pathology, Johns Hopkins University, Baltimore, MD, USA
| | - Michael Lim
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, USA
| | | | - Jon D Weingart
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, USA
| | - Peter B Barker
- Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - Martin G Pomper
- Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
| | - John Laterra
- Department of Neurology, Johns Hopkins University, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Peter C M van Zijl
- Department of Radiology, Johns Hopkins University, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | | | - Jinyuan Zhou
- Department of Radiology, Johns Hopkins University, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
| |
Collapse
|
136
|
Joo B, Han K, Choi YS, Lee SK, Ahn SS, Chang JH, Kang SG, Kim SH, Zhou J. Amide proton transfer imaging for differentiation of benign and atypical meningiomas. Eur Radiol 2017; 28:331-339. [PMID: 28687916 DOI: 10.1007/s00330-017-4962-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 12/17/2022]
Abstract
PURPOSE To investigate the difference in amide proton transfer (APT)-weighted signals between benign and atypical meningiomas and determine the value of APT imaging for differentiating the two. METHODS Fifty-seven patients with pathologically diagnosed meningiomas (benign, 44; atypical, 13), who underwent preoperative MRI with APT imaging between December 2014 and August 2016 were included. We compared normalised magnetisation transfer ratio asymmetry (nMTR asym ) values between benign and atypical meningiomas on APT-weighted images. Conventional MRI features were qualitatively assessed. Both imaging features were evaluated by multivariable logistic regression analysis. The discriminative value of MRI with and without nMTR asym was evaluated. RESULTS The nMTR asym of atypical meningiomas was significantly greater than that of benign meningiomas (2.46% vs. 1.67%; P < 0.001). In conventional MR images, benign and atypical meningiomas exhibited significant differences in maximum tumour diameter, non-skull base location, and heterogeneous enhancement. On multivariable logistic regression analysis, high nMTR asym was an independent predictor of atypical meningiomas (adjusted OR, 11.227; P = 0.014). The diagnostic performance of MRI improved with nMTR asym for predicting atypical meningiomas. CONCLUSION Atypical meningiomas exhibited significantly higher APT-weighted signal intensities than benign meningiomas. The discriminative value of conventional MRI improved significantly when combined with APT imaging for diagnosis of atypical meningioma. KEY POINTS • APT imaging is useful for differentiating between atypical and benign meningiomas. • Atypical meningiomas exhibited high APT-weighted signal intensity than benign meningiomas. • The diagnostic performance of MRI improved with nMTR asym for predicting atypical meningiomas.
Collapse
Affiliation(s)
- Bio Joo
- Department of Radiology, The Armed Forces Capital Hospital, Seongnam, Gyeonggi-do, Korea
| | - Kyunghwa Han
- Department of Radiology and Research Institute of Radiological Science, College of Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Yoon Seong Choi
- Department of Radiology and Research Institute of Radiological Science, College of Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Seung-Koo Lee
- Department of Radiology and Research Institute of Radiological Science, College of Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Sung Soo Ahn
- Department of Radiology and Research Institute of Radiological Science, College of Medicine, Yonsei University College of Medicine, Seoul, Korea. .,Department of Radiology, College of Medicine, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korea.
| | - Jong Hee Chang
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
| | - Seok-Gu Kang
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
| | - Se Hoon Kim
- Department of Pathology, Yonsei University College of Medicine, Seoul, Korea
| | - Jinyuan Zhou
- Division of MRI Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|
137
|
Heo HY, Zhang Y, Burton TM, Jiang S, Zhao Y, van Zijl PCM, Leigh R, Zhou J. Improving the detection sensitivity of pH-weighted amide proton transfer MRI in acute stroke patients using extrapolated semisolid magnetization transfer reference signals. Magn Reson Med 2017. [PMID: 28639301 DOI: 10.1002/mrm.26799] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE To quantify amide protein transfer (APT) effects in acidic ischemic lesions and assess the spatial-temporal relationship among diffusion, perfusion, and pH deficits in acute stroke patients. METHODS Thirty acute stroke patients were scanned at 3 T. Quantitative APT (APT# ) effects in acidic ischemic lesions were measured using an extrapolated semisolid magnetization transfer reference signal technique and compared with commonly used MTRasym (3.5ppm) or APT-weighted parameters. RESULTS The APT# images showed clear pH deficits in the ischemic lesion, whereas the MTRasym (3.5ppm) signals were slightly hypointense. The APT# contrast between acidic ischemic lesions and normal tissue in acute stroke patients was more than three times larger than MTRasym (3.5ppm) contrast (-1.45 ± 0.40% for APT# versus -0.39 ± 0.52% for MTRasym (3.5ppm), P < 4.6 × 10-4 ). Hypoperfused and acidic areas without an apparent diffusion coefficient abnormality were observed and assigned to an ischemic acidosis penumbra. Hypoperfused areas at normal pH were also observed and assigned to benign oligemia. Hyperintense APT signals were observed in a hemorrhage area in one case. CONCLUSIONS The quantitative APT study using the extrapolated semisolid magnetization transfer reference signal approach enhances APT MRI sensitivity to pH compared with conventional APT-weighted MRI, allowing more reliable delineation of an ischemic acidosis in the penumbra. Magn Reson Med 78:871-880, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Hye-Young Heo
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Yi Zhang
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Tina M Burton
- Neuro Vascular Brain Imaging Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Shanshan Jiang
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | | | - Peter C M van Zijl
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Richard Leigh
- Neuro Vascular Brain Imaging Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| |
Collapse
|
138
|
Ji Y, Zhou IY, Qiu B, Sun PZ. Progress toward quantitative in vivo chemical exchange saturation transfer (CEST) MRI. Isr J Chem 2017. [DOI: 10.1002/ijch.201700025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Yang Ji
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital; Harvard Medical School; Rm 2301, 149 13 Street Charlestown MA 02129
- Center for Biomedical Engineering, Department of Electronic Science and Technology; University of Science and Technology of China; Hefei China
| | - Iris Yuwen Zhou
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital; Harvard Medical School; Rm 2301, 149 13 Street Charlestown MA 02129
| | - Bensheng Qiu
- Center for Biomedical Engineering, Department of Electronic Science and Technology; University of Science and Technology of China; Hefei China
| | - Phillip Zhe Sun
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital; Harvard Medical School; Rm 2301, 149 13 Street Charlestown MA 02129
| |
Collapse
|
139
|
Kanazawa Y, Fushimi Y, Sakashita N, Okada T, Arakawa Y, Miyazaki M. B 1 Power Optimization for Chemical Exchange Saturation Transfer Imaging: A Phantom Study Using Egg White for Amide Proton Transfer Imaging Applications in the Human Brain. Magn Reson Med Sci 2017; 17:86-94. [PMID: 28566586 PMCID: PMC5760238 DOI: 10.2463/mrms.tn.2016-0069] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The chemical exchange saturation transfer (CEST) effect on an egg white (EW) suspension was investigated for optimization of magnetization transfer (MT) power (B1,rms) and pH dependency with the addition of lactic acid. Applying a higher MT pulse, B1,rms, Z-spectrum shows higher asymmetry and the magnetisation transfer ratio (MTR)asym signal increases to around 1–3.5 ppm, indicating a higher CEST effect. Amide proton transfer (APT) at 3.5 ppm shows a signal elevation in MTRasym with the application of higher B1,rms power and high pH. In addition, the hydroxyl proton signal in MTRasym increases as pH is reduced by lactic acid. In Z-spectrum of B1,rms at 1.0 μT and 2.0 μT, the dependence on CEST effect of amide proton and hydroxyl proton could be observed by using an EW suspension phantom. The CEST MT power was optimized on the EW suspension phantom with pH dependency and further confirmed on volunteers. In addition, APT imaging at 3.5 ppm using B1,rms at 1.0 μT performed on two human brains with different pathophysiological conditions indicated appropriate ATP effect.
Collapse
Affiliation(s)
- Yuki Kanazawa
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University.,Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Yasutaka Fushimi
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University
| | | | - Tomohisa Okada
- Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University
| | - Yoshiki Arakawa
- Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto University
| | - Mitsue Miyazaki
- Toshiba Medical Systems Corporation.,Toshiba Medical Research Institute, 706 Deerpath Dr. Vernon Hills
| |
Collapse
|
140
|
Wang F, Zu Z, Wu R, Wu TL, Gore JC, Chen LM. MRI evaluation of regional and longitudinal changes in Z-spectra of injured spinal cord of monkeys. Magn Reson Med 2017; 79:1070-1082. [PMID: 28547862 DOI: 10.1002/mrm.26756] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 04/21/2017] [Accepted: 04/22/2017] [Indexed: 01/21/2023]
Abstract
PURPOSE In principle, MR methods that exploit magnetization transfer (MT) may be used to quantify changes in the molecular composition of tissues after injury. The ability to track such changes in injured spinal cord may allow more precise assessment of the state of neural tissues. METHODS Z-Spectra were obtained from the cervical spinal cord before and after a unilateral dorsal column lesion in monkeys at 9.4T. The amplitudes of chemical exchange saturation transfer (CEST) and nuclear Overhauser enhancement (NOE) effects from multiple proton pools, along with nonspecific semisolid MT effects from immobile macromolecules, were quantified using a five-peak Lorenzian fitting of each Z-spectrum. RESULTS Abnormal tissues/cysts that formed around lesion sites exhibited relatively low correlations between their Z-spectra and that of normal gray matter (GM). Compared with normal GM, cysts showed strong CEST but weak semisolid MT and NOE effects after injury. The abnormal tissues around lesion sites were heterogeneous and showed different regional Z-spectra. Different regional correlations between proton pools were observed. Longitudinally, injured spinal cord tissue exhibited remarkable recovery in all subjects. CONCLUSION Characterization of multiple proton pools from Z-spectra permitted noninvasive, regional, quantitative assessments of changes in tissue composition of injured spinal cord over time. Magn Reson Med 79:1070-1082, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Feng Wang
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Zhongliang Zu
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Ruiqi Wu
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Tung-Lin Wu
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - John C Gore
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Li Min Chen
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| |
Collapse
|
141
|
Khlebnikov V, Windschuh J, Siero JC, Zaiss M, Luijten PR, Klomp DW, Hoogduin H. On the transmit field inhomogeneity correction of relaxation-compensated amide and NOE CEST effects at 7 T. NMR IN BIOMEDICINE 2017; 30:e3687. [PMID: 28111824 PMCID: PMC5412922 DOI: 10.1002/nbm.3687] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 11/22/2016] [Accepted: 11/22/2016] [Indexed: 05/08/2023]
Abstract
High field MRI is beneficial for chemical exchange saturation transfer (CEST) in terms of high SNR, CNR, and chemical shift dispersion. These advantages may, however, be counter-balanced by the increased transmit field inhomogeneity normally associated with high field MRI. The relatively high sensitivity of the CEST contrast to B1 inhomogeneity necessitates the development of correction methods, which is essential for the clinical translation of CEST. In this work, two B1 correction algorithms for the most studied CEST effects, amide-CEST and nuclear Overhauser enhancement (NOE), were analyzed. Both methods rely on fitting the multi-pool Bloch-McConnell equations to the densely sampled CEST spectra. In the first method, the correction is achieved by using a linear B1 correction of the calculated amide and NOE CEST effects. The second method uses the Bloch-McConnell fit parameters and the desired B1 amplitude to recalculate the CEST spectra, followed by the calculation of B1 -corrected amide and NOE CEST effects. Both algorithms were systematically studied in Bloch-McConnell equations and in human data, and compared with the earlier proposed ideal interpolation-based B1 correction method. In the low B1 regime of 0.15-0.50 μT (average power), a simple linear model was sufficient to mitigate B1 inhomogeneity effects on a par with the interpolation B1 correction, as demonstrated by a reduced correlation of the CEST contrast with B1 in both the simulations and the experiments.
Collapse
Affiliation(s)
- Vitaliy Khlebnikov
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Johannes Windschuh
- Division of Medical Physics in RadiologyDeutsches Krebsforschungszentrum (DKFZ) [German Cancer Research Center]HeidelbergGermany
| | - Jeroen C.W. Siero
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
- Spinoza Centre for NeuroimagingAmsterdamThe Netherlands
| | - Moritz Zaiss
- Division of Medical Physics in RadiologyDeutsches Krebsforschungszentrum (DKFZ) [German Cancer Research Center]HeidelbergGermany
| | - Peter R. Luijten
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Dennis W.J. Klomp
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Hans Hoogduin
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| |
Collapse
|
142
|
van Zijl PCM, Lam WW, Xu J, Knutsson L, Stanisz GJ. Magnetization Transfer Contrast and Chemical Exchange Saturation Transfer MRI. Features and analysis of the field-dependent saturation spectrum. Neuroimage 2017; 168:222-241. [PMID: 28435103 DOI: 10.1016/j.neuroimage.2017.04.045] [Citation(s) in RCA: 205] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 11/30/2022] Open
Abstract
Magnetization Transfer Contrast (MTC) and Chemical Exchange Saturation Transfer (CEST) experiments measure the transfer of magnetization from molecular protons to the solvent water protons, an effect that becomes apparent as an MRI signal loss ("saturation"). This allows molecular information to be accessed with the enhanced sensitivity of MRI. In analogy to Magnetic Resonance Spectroscopy (MRS), these saturation data are presented as a function of the chemical shift of participating proton groups, e.g. OH, NH, NH2, which is called a Z-spectrum. In tissue, these Z-spectra contain the convolution of multiple saturation transfer effects, including nuclear Overhauser enhancements (NOEs) and chemical exchange contributions from protons in semi-solid and mobile macromolecules or tissue metabolites. As a consequence, their appearance depends on the magnetic field strength (B0) and pulse sequence parameters such as B1 strength, pulse shape and length, and interpulse delay, which presents a major problem for quantification and reproducibility of MTC and CEST effects. The use of higher B0 can bring several advantages. In addition to higher detection sensitivity (signal-to-noise ratio, SNR), both MTC and CEST studies benefit from longer water T1 allowing the saturation transferred to water to be retained longer. While MTC studies are non-specific at any field strength, CEST specificity is expected to increase at higher field because of a larger chemical shift dispersion of the resonances of interest (similar to MRS). In addition, shifting to a slower exchange regime at higher B0 facilitates improved detection of the guanidinium protons of creatine and the inherently broad resonances of the amine protons in glutamate and the hydroxyl protons in myoinositol, glycogen, and glucosaminoglycans. Finally, due to the higher mobility of the contributing protons in CEST versus MTC, many new pulse sequences can be designed to more specifically edit for CEST signals and to remove MTC contributions.
Collapse
Affiliation(s)
- Peter C M van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
| | - Wilfred W Lam
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Jiadi Xu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Linda Knutsson
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Greg J Stanisz
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, Lublin, Poland.
| |
Collapse
|
143
|
Zhang Y, Liu X, Zhou J, Bottomley PA. Ultrafast compartmentalized relaxation time mapping with linear algebraic modeling. Magn Reson Med 2017; 79:286-297. [PMID: 28401643 DOI: 10.1002/mrm.26675] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 02/17/2017] [Accepted: 02/19/2017] [Indexed: 12/28/2022]
Abstract
PURPOSE To dramatically accelerate compartmental-average longitudinal (T1 ) and transverse (T2 ) relaxation measurements using the minimal-acquisition linear algebraic modeling (SLAM) method, and to validate it in phantoms and humans. METHODS Relaxation times were imaged at 3 Tesla in phantoms, in the abdomens of six volunteers, and in six brain tumor patients using standard inversion recovery and multi-spin-echo sequences. k-space was fully sampled to provide reference T1 and T2 measurements, and SLAM was performed using a limited set of phase encodes from central k-space. Anatomical compartments were segmented on scout images post-acquisition, and SLAM reconstruction was implemented using two algorithms. Compartment-average T1 and T2 measurements were determined retroactively from fully sampled data sets, and proactively from SLAM data sets at acceleration factors of up to 16. Values were compared with reference measurements. The compartment's localization properties were analyzed using the discrete spatial response function. RESULTS At 16-fold acceleration, compartment-average SLAM T1 measurements agreed with the full k-space compartment-average results to within 0.0% ± 0.7%, 1.4% ± 3.4%, and 0.5% ± 2.9% for phantom, abdominal, and brain T1 measurements, respectively. The corresponding T2 measurements agreed within 0.2% ± 1.9%, 0.9% ± 7.9%, and 0.4% ± 5.8%, respectively. CONCLUSION SLAM can dramatically accelerate relaxation time measurements when compartmental or lesion-average values can suffice, or when standard relaxometry is precluded by scan-time limitations. Magn Reson Med 79:286-297, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Yi Zhang
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Xiaoyang Liu
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Paul A Bottomley
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
| |
Collapse
|
144
|
Ma X, Bai Y, Lin Y, Hong X, Liu T, Ma L, Haacke EM, Zhou J, Wang J, Wang M. Amide proton transfer magnetic resonance imaging in detecting intracranial hemorrhage at different stages: a comparative study with susceptibility weighted imaging. Sci Rep 2017; 7:45696. [PMID: 28374764 PMCID: PMC5379544 DOI: 10.1038/srep45696] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 03/03/2017] [Indexed: 02/08/2023] Open
Abstract
Amide proton transfer (APT) imaging is a noninvasive molecular magnetic resonance imaging (MRI) technique based on the chemical exchange-dependent saturation transfer mechanism. The purpose of this study was to investigate the diagnostic performance of APT MRI in detecting intracranial hemorrhage (ICH) at hyperacute, acute and subacute stages by comparing with susceptibility weighted imaging (SWI). APT MRI and SWI were performed on 33 included patients with ICH by using a 3-T MRI unit. A two-sided Mann-Whitney U test was used to detect differences in APT-weighted (APTw) and SWI signal intensities of ICH at hyperacute, acute and subacute stages. Receiver operating characteristic analysis was used to assess the diagnostic utilities of APT MRI and SWI. Our results showed that APT MRI could detect ICH at hyperacute, acute and subacute stages. Therefore, APTw signal intensity may serve as a reliable, noninvasive imaging biomarker for detecting ICH at hyperacute, acute and subacute stages. Moreover, APT MRI could provide additional information for the ICH compared with SWI.
Collapse
Affiliation(s)
- Xiaoyue Ma
- Department of Radiology, Zhengzhou University People's Hospital &Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - Yan Bai
- Department of Radiology, Zhengzhou University People's Hospital &Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - Yusong Lin
- Cooperative Innovation Center of Internet Healthcare &School of Software and Applied Technology, Zhengzhou, Henan, China
| | - Xiaohua Hong
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Taiyuan Liu
- Department of Radiology, Zhengzhou University People's Hospital &Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - Lun Ma
- Department of Radiology, Zhengzhou University People's Hospital &Henan Provincial People's Hospital, Zhengzhou, Henan, China
| | - E Mark Haacke
- Department of Radiology, Wayne State University, Detroit, Michigan, USA
| | - Jinyuan Zhou
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jian Wang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Meiyun Wang
- Department of Radiology, Zhengzhou University People's Hospital &Henan Provincial People's Hospital, Zhengzhou, Henan, China
| |
Collapse
|
145
|
Zheng Y, Wang XM. Measurement of Lactate Content and Amide Proton Transfer Values in the Basal Ganglia of a Neonatal Piglet Hypoxic-Ischemic Brain Injury Model Using MRI. AJNR Am J Neuroradiol 2017; 38:827-834. [PMID: 28154122 DOI: 10.3174/ajnr.a5066] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 11/06/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE As amide proton transfer imaging is sensitive to protein content and intracellular pH, it has been widely used in the nervous system, including brain tumors and stroke. This work aimed to measure the lactate content and amide proton transfer values in the basal ganglia of a neonatal piglet hypoxic-ischemic brain injury model by using MR spectroscopy and amide proton transfer imaging. MATERIALS AND METHODS From 58 healthy neonatal piglets (3-5 days after birth; weight, 1-1.5 kg) selected initially, 9 piglets remained in the control group and 43 piglets, in the hypoxic-ischemic brain injury group. Single-section amide proton transfer imaging was performed at the coronal level of the basal ganglia. Amide proton transfer values of the bilateral basal ganglia were measured in all piglets. The ROI of MR spectroscopy imaging was the right basal ganglia, and the postprocessing was completed with LCModel software. RESULTS After hypoxic-ischemic insult, the amide proton transfer values immediately decreased, and at 0-2 hours, they remained at their lowest level. Thereafter, they gradually increased and finally exceeded those of the control group at 48-72 hours. After hypoxic-ischemic insult, the lactate content increased immediately, was maximal at 2-6 hours, and then gradually decreased to the level of the control group. The amide proton transfer values were negatively correlated with lactate content (r = -0.79, P < .05). CONCLUSIONS This observation suggests that after hypoxic-ischemic insult, the recovery of pH was faster than that of lactate homeostasis.
Collapse
Affiliation(s)
- Y Zheng
- From the Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, PR China
| | - X-M Wang
- From the Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, PR China.
| |
Collapse
|
146
|
Jeong HK, Han K, Zhou J, Zhao Y, Choi YS, Lee SK, Ahn SS. Characterizing amide proton transfer imaging in haemorrhage brain lesions using 3T MRI. Eur Radiol 2017; 27:1577-1584. [PMID: 27380905 PMCID: PMC5746025 DOI: 10.1007/s00330-016-4477-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 05/14/2016] [Accepted: 06/20/2016] [Indexed: 12/12/2022]
Abstract
OBJECTIVES The aim of this study was to characterize amide proton transfer (APT)-weighted signals in acute and subacute haemorrhage brain lesions of various underlying aetiologies. METHODS Twenty-three patients with symptomatic haemorrhage brain lesions including tumorous (n = 16) and non-tumorous lesions (n = 7) were evaluated. APT imaging was performed and analyzed with magnetization transfer ratio asymmetry (MTR asym ). Regions of interest were defined as the enhancing portion (when present), acute or subacute haemorrhage, and normal-appearing white matter based on anatomical MRI. MTR asym values were compared among groups and components using a linear mixed model. RESULTS MTR asym values were 3.68 % in acute haemorrhage, 1.6 % in subacute haemorrhage, 2.65 % in the enhancing portion, and 0.38 % in normal white matter. According to the linear mixed model, the distribution of MTR asym values among components was not significantly different between tumour and non-tumour groups. MTR asym in acute haemorrhage was significantly higher than those in the other regions regardless of underlying pathology. CONCLUSIONS Acute haemorrhages showed high MTR asym regardless of the underlying pathology, whereas subacute haemorrhages showed lower MTR asym than acute haemorrhages. These results can aid in the interpretation of APT imaging in haemorrhage brain lesions. KEY POINTS • Acute haemorrhages show significantly higher MTR asym values than subacute haemorrhages. • MTR asym is higher in acute haemorrhage than in enhancing tumour tissue. • MTR asym in haemorrhage does not differ between tumorous and non-tumorous lesions.
Collapse
Affiliation(s)
- Ha-Kyu Jeong
- Philips Korea, Seoul, Korea
- Korea Basic Science Institute, Chungcheongbuk-do, Korea
| | - Kyunghwa Han
- Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korea
- Yonsei Biomedical Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Jinyuan Zhou
- Division of MRI Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yansong Zhao
- MR Clinical Science, Philips Healthcare, Cleveland, OH, USA
| | - Yoon Seong Choi
- Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korea
| | - Seung-Koo Lee
- Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korea
| | - Sung Soo Ahn
- Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korea.
| |
Collapse
|
147
|
Song G, Li C, Luo X, Zhao X, Zhang S, Zhang Y, Jiang S, Wang X, Chen Y, Chen H, Gong T, Zhou J, Chen M. Evolution of Cerebral Ischemia Assessed by Amide Proton Transfer-Weighted MRI. Front Neurol 2017; 8:67. [PMID: 28303115 PMCID: PMC5332413 DOI: 10.3389/fneur.2017.00067] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 02/15/2017] [Indexed: 12/25/2022] Open
Abstract
Amide proton transfer-weighted (APTW) magnetic resonance imaging (MRI) has recently become a potentially important tool for evaluating acidosis in ischemic stroke. The purpose of this study was to evaluate the dynamic pH-related changes in the lesions in patients with ischemia. Thirty-nine patients with ischemic stroke (symptom onset to imaging time ranging 2 h–7 days) were examined with a 3.0-T MRI system. Patients were divided into four groups: at the hyperacute stage (onset time ≤ 6 h), at the acute stage (6 h < onset time ≤ 48 h), at the early subacute stage (48 h < onset time ≤ 96 h), and at the late subacute stage (96 h < onset time ≤ 168 h). The APTW signal intensities were quantitatively measured in multiple ischemic regions for each patient. Compared with the contralateral normal white matter, APTW signals were significantly lower in ischemic tissue for all four stages (P < 0.05). The APTW signal intensities (APTWave and APTWmin) increased consistently with onset time (R2 = 0.11, P = 0.040; R2 = 0.13, P = 0.022, respectively). APTWmax–min showed a continued reduction with onset time (R2 = 0.44, P < 0.001). Our results suggest that persistent tissue acidification could occur after ischemia, and as the time from stroke onset increases, the acidotic environment would alleviate. APTW signal intensities could reflect pH-weighted properties in ischemic tissue at different stages and time points.
Collapse
Affiliation(s)
- Guodong Song
- Department of Radiology, Beijing Hospital, National Center of Gerontology, Beijing, China; Graduate School of Peking Union Medical College, Beijing, China
| | - Chunmei Li
- Department of Radiology, Beijing Hospital, National Center of Gerontology , Beijing , China
| | - Xiaojie Luo
- Department of Radiology, Beijing Hospital, National Center of Gerontology , Beijing , China
| | - Xuna Zhao
- Department of Radiology, Johns Hopkins University , Baltimore, MD , USA
| | - Shuai Zhang
- Department of Radiology, Beijing Hospital, National Center of Gerontology, Beijing, China; Graduate School of Peking Union Medical College, Beijing, China
| | - Yi Zhang
- Department of Radiology, Johns Hopkins University , Baltimore, MD , USA
| | - Shanshan Jiang
- Department of Radiology, Johns Hopkins University , Baltimore, MD , USA
| | - Xianlong Wang
- Department of Radiology, Zhujiang Hospital of Southern Medical University , Guangzhou , China
| | - Yuhui Chen
- Department of Neurology, Beijing Hospital, National Center of Gerontology , Beijing , China
| | - Haibo Chen
- Department of Neurology, Beijing Hospital, National Center of Gerontology , Beijing , China
| | - Tao Gong
- Department of Neurology, Beijing Hospital, National Center of Gerontology , Beijing , China
| | - Jinyuan Zhou
- Department of Radiology, Johns Hopkins University , Baltimore, MD , USA
| | - Min Chen
- Department of Radiology, Beijing Hospital, National Center of Gerontology, Beijing, China; Graduate School of Peking Union Medical College, Beijing, China
| |
Collapse
|
148
|
Magnetization Transfer and Amide Proton Transfer MRI of Neonatal Brain Development. BIOMED RESEARCH INTERNATIONAL 2016; 2016:3052723. [PMID: 27885356 PMCID: PMC5112326 DOI: 10.1155/2016/3052723] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 10/10/2016] [Indexed: 11/18/2022]
Abstract
Purpose. This study aims to evaluate the process of brain development in neonates using combined amide proton transfer (APT) imaging and conventional magnetization transfer (MT) imaging. Materials and Methods. Case data were reviewed for all patients hospitalized in our institution's neonatal ward. Patients underwent APT and MT imaging (a single protocol) immediately following the routine MR examination. Single-slice APT/MT axial imaging was performed at the level of the basal ganglia. APT and MT ratio (MTR) measurements were performed in multiple brain regions of interest (ROIs). Data was statistically analyzed in order to assess for significant differences between the different regions of the brain or correlation with patient gestational age. Results. A total of 38 neonates were included in the study, with ages ranging from 27 to 41 weeks' corrected gestational age. There were statistically significant differences in both APT and MTR measurements between the frontal lobes, basal ganglia, and occipital lobes (APT: frontal lobe versus occipital lobe P = 0.031 and other groups P = 0.00; MTR: frontal lobe versus occipital lobe P = 0.034 and other groups P = 0.00). Furthermore, APT and MTR in above brain regions exhibited positive linear correlations with patient gestational age. Conclusions. APT/MT imaging can provide valuable information about the process of the neonatal brain development at the molecular level.
Collapse
|
149
|
Khlebnikov V, Siero JCW, Wijnen J, Visser F, Luijten PR, Klomp DWJ, Hoogduin H. Is there any difference in Amide and NOE CEST effects between white and gray matter at 7T? JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 272:82-86. [PMID: 27662404 DOI: 10.1016/j.jmr.2016.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 09/14/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
Measurement of Chemical Exchange Saturation Transfer (CEST) is providing tissue physiology dependent contrast, e.g. by looking at Amide and NOE (Nuclear Overhauser Enhancement) effects. CEST is unique in providing quantitative metabolite information at high imaging resolution. However, direct comparison of Amide and NOE effects between different tissues may result in wrong conclusions on the metabolite concentration due to the additional contributors to the observed CEST contrast, such as water content (WC) and water T1 relaxation (T1w). For instance, there are multiple contradictory reports in the literature on Amide and NOE effects in white matter (WM) and gray matter (GM) at 7T. This study shows that at 7T, tissue water T1 relaxation is a stronger contributor to CEST contrasts than WC. After water T1 correction, there was no difference in Amide effects between WM and GM, whereas WM/GM contrast was enhanced for NOE effects.
Collapse
Affiliation(s)
- Vitaliy Khlebnikov
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Jeroen C W Siero
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jannie Wijnen
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Peter R Luijten
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hans Hoogduin
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| |
Collapse
|
150
|
Harris RJ, Cloughesy TF, Liau LM, Nghiemphu PL, Lai A, Pope WB, Ellingson BM. Simulation, phantom validation, and clinical evaluation of fast pH-weighted molecular imaging using amine chemical exchange saturation transfer echo planar imaging (CEST-EPI) in glioma at 3 T. NMR IN BIOMEDICINE 2016; 29:1563-1576. [PMID: 27717216 DOI: 10.1002/nbm.3611] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 07/14/2016] [Accepted: 07/29/2016] [Indexed: 06/06/2023]
Abstract
Acidity within the extracellular milieu is a hallmark of cancer. There is a current need for fast, high spatial resolution pH imaging techniques for clinical evaluation of cancers, including gliomas. Chemical exchange saturation transfer (CEST) MRI targeting fast-exchanging amine protons can be used to obtain high-resolution pH-weighted images, but conventional CEST acquisition strategies are slow. There is also a need for more accurate MR simulations to better understand the effects of amine CEST pulse sequence parameters on pH-weighted image contrast. In the current study we present a simulation of amine CEST contrast specific for a newly developed CEST echoplanar imaging (EPI) pulse sequence. The accuracy of the simulations was validated by comparing the exchange rates and Z-spectrum under a variety of conditions using physical phantoms of glutamine with different pH values. The effects of saturation pulse shapes, pulse durations, pulse train lengths, repetition times, and relaxation rates of bulk water and exchangeable amine protons on the CEST signal were explored for normal-appearing white matter (NAWM), glioma, and cerebrospinal fluid. Last, 18 patients with WHO II-IV gliomas were evaluated. Results showed that the Z-spectrum was highly dependent on saturation pulse shape, repetition time, saturation amplitude, magnetic field strength, and T2 within bulk water; however, the Z-spectrum was only minimally influenced by saturation pulse duration and the specific relaxation rates of amine protons. Results suggest that a Gaussian saturation pulse train consisting of 3 × 100 ms pulses using the minimum allowable repetition time is optimal for achieving over 90% available contrast across all tissues. Results also demonstrate that high saturation pulse amplitude and scanner field strength (>3 T) are necessary for adequate endogenous pH-weighted amine CEST contrast. pH-weighted amine CEST contrast increased with increasing tumor grade, with glioblastoma showing significantly higher contrast compared with WHO II or III gliomas.
Collapse
Affiliation(s)
- Robert J Harris
- UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Department of Physics and Biology in Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Timothy F Cloughesy
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Linda M Liau
- UCLA Brain Research Institute (BRI), David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- Department of Neurosurgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Phioanh L Nghiemphu
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Albert Lai
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
- UCLA Brain Research Institute (BRI), David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Whitney B Pope
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Benjamin M Ellingson
- UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.
- Department of Physics and Biology in Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.
- UCLA Brain Research Institute (BRI), David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.
- Department of Bioengineering, Henry Samueli School of Engineering and Applied Science, University of California Los Angeles, Los Angeles, California, USA.
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.
| |
Collapse
|