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Schüre JR, Shrestha M, Breuer S, Deichmann R, Hattingen E, Wagner M, Pilatus U. The pH sensitivity of APT-CEST using phosphorus spectroscopy as a reference method. NMR IN BIOMEDICINE 2019; 32:e4125. [PMID: 31322308 DOI: 10.1002/nbm.4125] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 05/08/2019] [Accepted: 05/08/2019] [Indexed: 06/10/2023]
Abstract
The pH value is a potential physiological marker for clinical diagnosis as it is altered in pathologies such as tumors. While intracellular pH can be measured noninvasively via phosphorus spectroscopy (31 P MRSI), Amide Proton Transfer-Chemical Exchange Saturation Transfer (APT-CEST) MRI has been suggested as an alternative method for pH quantification. To assess the suitability of APT-CEST contrast for pH quantification, two approaches (magnetization transfer ratio asymmetry [MTRasym ] and Lorentzian difference analysis [LDA]) for analyzing the Z-spectrum have been correlated with pH values obtained by 31 P MRSI. Fourteen patients with glioblastoma and 12 healthy controls were included. In contrast to MTRasym , the LDA is modeling the direct water saturation and the semi-solid magnetization transfer, allowing a separate evaluation of the aliphatic nuclear Overhauser effect and the APT-CEST. The results of our study show that the pH values obtained by 31 P MRSI correspond well with both methods describing the APT-CEST contrast. Two-sample t-test showed significant differences in MTRasym , LDA and pH obtained by 31 P MRSI for regions of interest in glioblastoma, contralateral control areas and normal appearing white matter (P < 0.001). A slightly improved correlation between the amide signal and pH was found after performing LDA (r = 0.78) compared with MTRasym (r = 0.70). While both methods can be used to monitor pH changes, the LDA approach appears to be better suited.
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Affiliation(s)
- Jan-Rüdiger Schüre
- Department of Neuroradiology, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Manoj Shrestha
- Brain Imaging Center (BIC), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Stella Breuer
- Department of Neuroradiology, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Ralf Deichmann
- Brain Imaging Center (BIC), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Elke Hattingen
- Department of Neuroradiology, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Marlies Wagner
- Department of Neuroradiology, University Hospital Frankfurt, Frankfurt am Main, Germany
| | - Ulrich Pilatus
- Department of Neuroradiology, University Hospital Frankfurt, Frankfurt am Main, Germany
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Su C, Zhao L, Li S, Jiang J, Cai K, Shi J, Yao Y, Ao Q, Zhang G, Shen N, Hu S, Zhang J, Qin Y, Zhu W. Amid proton transfer (APT) and magnetization transfer (MT) MRI contrasts provide complimentary assessment of brain tumors similarly to proton magnetic resonance spectroscopy imaging (MRSI). Eur Radiol 2018; 29:1203-1210. [PMID: 30105412 DOI: 10.1007/s00330-018-5615-8] [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: 01/09/2018] [Revised: 05/18/2018] [Accepted: 06/18/2018] [Indexed: 02/03/2023]
Abstract
OBJECTIVES Using MRSI as comparison, we aimed to explore the difference between amide proton transfer (APT) MRI and conventional semi-solid magnetization transfer ratio (MTR) MRI, and to investigate if molecular APT and structural MTR can provide complimentary information in assessing brain tumors. METHODS Seventeen brain tumor patients and 17 age- and gender-matched volunteers were included and scanned with anatomical MRI, APT and MT-weighted MRI, and MRSI. Multi-voxel choline (Cho) and N-acetylaspartic acid (NAA) signals were quantified from MRSI and compared with MTR and MTRasym(3.5ppm) contrasts averaged from corresponding voxels. Correlations between contrasts were explored voxel-by-voxel by pooling values from all voxels into Pearson's correlation analysis. Differences in correlation coefficients were tested with the Z-test (set at p<0.05). RESULTS APT and MT provide good contrast and quantitative parameters in tumor imaging, as do the metabolite (Cho and NAA) maps. MTRasym(3.5ppm) significantly correlated with MTR (R=-0.61, p<0.0001), Cho (R=0.568, p<0.0001) and NAA (R=-0.619, p<0.0001) in tumors, and MTR also significantly correlated with Cho (R=-0.346, p<0.0001) and NAA (R=0.624, p<0.0001). In healthy volunteers, MTRasym(3.5ppm) was non-significantly correlated with MTR (R=-0.049, p=0.239), Cho (R=0.030, p=0.478) and NAA (R=-0.083, p=0.046). Significant correlations were found among MTR with Cho (R=0.199, p<0.0001) and NAA (R=0.263, p<0.0001) in the group of healthy volunteers with lower correlation R values than those in tumor patients. CONCLUSIONS APT and MT could provide independent and supplementary information for the comprehensive assessment of molecular and structural changes due to brain tumor cancerogenesis. KEY POINTS • MTR asym(3.5ppm) positively correlated with Cho while negatively with NAA in tumors. • MTR positively correlated with NAA while negatively with Cho in tumors. • Combining APT/MT provides molecular and structural information similarly to MRSI.
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Affiliation(s)
- Changliang Su
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Lingyun Zhao
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Shihui Li
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Jingjing Jiang
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Kejia Cai
- The Department of Radiology and Bioengineering, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Jingjing Shi
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Yihao Yao
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Qilin Ao
- Department of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Guiling Zhang
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Nanxi Shen
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Shan Hu
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Jiaxuan Zhang
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Yuanyuan Qin
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China
| | - Wenzhen Zhu
- Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 JieFang Avenue, Hankou, Wuhan, 430030, People's Republic of China.
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Garbow JR, Tsien CI, Beeman SC. Preclinical MRI: Studies of the irradiated brain. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 292:73-81. [PMID: 29705034 PMCID: PMC6029718 DOI: 10.1016/j.jmr.2018.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/20/2018] [Accepted: 03/28/2018] [Indexed: 06/08/2023]
Abstract
Radiation therapy (RT) plays a central role in the treatment of primary brain tumors. However, despite recent advances in RT treatment, local recurrences following therapy remain common. Radiation necrosis (RN) is a severe, late complication of radiation therapy in the brain. RN is a serious clinical problem often associated with devastating neurologic complications. Therapeutic strategies, including neuroprotectants, have been described, but have not been widely translated in routine clinical use. We have developed a mouse model that recapitulates all of the major pathologic features of late-onset RN for the purposes of characterizing the basic pathogenesis of RN, identifying non-invasive (imaging) biomarkers of RN that might allow for the radiologic discernment of tumor and RN, systematic testing of tumor and RN therapeutics, and exploring the complex interplay between RN pathogenesis and tumor recurrence. Herein, we describe the fundamental clinical challenges associated with RN and the progress made towards addressing these challenges by combining our novel mouse model of late-onset RN and magnetic resonance imaging (MRI). MRI techniques discussed include conventional T1- and T2-weighted imaging, diffusion-weighted imaging, magnetization transfer, and measures of tissue oxygenation. Studies of RN mitigation and neuroprotection are described, including the use of anti-VEGF antibodies, and inhibitors of GSK-3β, HIF-1α, and CXCR4. We conclude with some future perspectives on the irradiated brain and the study and treatment of recurrent tumor growing in an irradiated tumor microenvironment.
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Affiliation(s)
- Joel R Garbow
- Department of Radiology, Washington University, Saint Louis, MO, United States; The Alvin J. Siteman Cancer Center, Washington University, Saint Louis, MO, United States.
| | - Christina I Tsien
- Department of Radiation Oncology, Washington University, Saint Louis, MO, United States
| | - Scott C Beeman
- Department of Radiology, Washington University, Saint Louis, MO, United States
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4
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Ainsworth NL, McLean MA, McIntyre DJ, Honess DJ, Brown AM, Harden SV, Griffiths JR. Quantitative and textural analysis of magnetization transfer and diffusion images in the early detection of brain metastases. Magn Reson Med 2017; 77:1987-1995. [PMID: 27279574 PMCID: PMC5412685 DOI: 10.1002/mrm.26257] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 12/17/2022]
Abstract
PURPOSE The sensitivity of the magnetization transfer ratio (MTR) and apparent diffusion coefficient (ADC) for early detection of brain metastases was investigated in mice and humans. METHODS Mice underwent MRI twice weekly for up to 31 d following intracardiac injection of the brain-homing breast cancer cell line MDA-MB231-BR. Patients with small cell lung cancer underwent quarterly MRI for 1 year. MTR and ADC were measured in regions of metastasis and matched contralateral tissue at the final time point and in registered regions at earlier time points. Texture analysis and linear discriminant analysis were performed to detect metastasis-containing slices. RESULTS Compared with contralateral tissue, mouse metastases had significantly lower MTR and higher ADC at the final time point. Some lesions were visible at earlier time points on the MTR and ADC maps: 24% of these were not visible on corresponding T2 -weighted images. Texture analysis using the MTR maps showed 100% specificity and 98% sensitivity for metastasis at the final time point, with 77% sensitivity 2-4 d earlier and 46% 5-8 d earlier. Only 2 of 16 patients developed metastases, and their penultimate scans were normal. CONCLUSIONS Some brain metastases may be detected earlier on MTR than conventional T2 ; however, the small gain is unlikely to justify "predictive" MRI. Magn Reson Med 77:1987-1995, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
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Affiliation(s)
- Nicola L. Ainsworth
- Cancer Research UK Cambridge InstituteUniversity of CambridgeLi Ka Shing CentreRobinson WayCambridgeCB2 0RE
| | - Mary A. McLean
- Cancer Research UK Cambridge InstituteUniversity of CambridgeLi Ka Shing CentreRobinson WayCambridgeCB2 0RE
| | - Dominick J.O. McIntyre
- Cancer Research UK Cambridge InstituteUniversity of CambridgeLi Ka Shing CentreRobinson WayCambridgeCB2 0RE
| | - Davina J. Honess
- Cancer Research UK Cambridge InstituteUniversity of CambridgeLi Ka Shing CentreRobinson WayCambridgeCB2 0RE
| | - Anna M. Brown
- Cancer Research UK Cambridge InstituteUniversity of CambridgeLi Ka Shing CentreRobinson WayCambridgeCB2 0RE
| | - Susan V Harden
- Department of OncologyAddenbrooke's HospitalHills RoadCambridgeCB2 0QQ
| | - John R. Griffiths
- Cancer Research UK Cambridge InstituteUniversity of CambridgeLi Ka Shing CentreRobinson WayCambridgeCB2 0RE
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5
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Desmond KL, Mehrabian H, Chavez S, Sahgal A, Soliman H, Rola R, Stanisz GJ. Chemical exchange saturation transfer for predicting response to stereotactic radiosurgery in human brain metastasis. Magn Reson Med 2016; 78:1110-1120. [PMID: 27690156 DOI: 10.1002/mrm.26470] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 08/23/2016] [Accepted: 08/29/2016] [Indexed: 12/19/2022]
Abstract
PURPOSE The purpose of this work was to determine the predictive value of chemical exchange saturation transfer (CEST) metrics in brain metastases treated with stereotactic radiosurgery (SRS). METHODS CEST spectra at a radiofrequency power of 0.52 µT were collected on a 3 Tesla (T) magnetic resonance imaging from 25 patients at three time points: pretreatment, 1 week, and 1 month post-treatment. Amide proton transfer-weighted images and maps of the amplitude and width of Lorentzian-shaped CEST peaks and the relaxation-compensated AREX metric were constructed at the offset frequencies of amide, amine, and relayed nuclear Overhauser effect (NOE) from aliphatic groups as well as the broad magnetization transfer effect. Pretreatment CEST metrics, as well as CEST metric changes at 1 week post-treatment, were compared to changes in tumor volume at 1 month. RESULTS Significant (P < 0.05) 1-week predictive metrics included NOE peak amplitude (R = 0.69) in normal-appearing white matter (NAWM) and width (R = -0.55) in tumor. Baseline NOE in contralateral NAWM was negatively correlated (R = -0.69) with volume changes at 1 month. Metrics-defined outside tumor margins had higher correlation with volume changes than tumor regions of interest. CONCLUSION CEST metrics, in particular, the NOE peak amplitude, can predict volume changes 1 month post-SRS. Magn Reson Med 78:1110-1120, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Kimberly L Desmond
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Hatef Mehrabian
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.,Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Sofia Chavez
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Arjun Sahgal
- Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Hany Soliman
- Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Radoslaw Rola
- Department of Neurosurgery and Pediatric Neurosurgery, Medical University, Lublin, Poland
| | - Greg J Stanisz
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.,Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,Department of Neurosurgery and Pediatric Neurosurgery, Medical University, Lublin, Poland
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6
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Shiroishi MS, Cen SY, Tamrazi B, D'Amore F, Lerner A, King KS, Kim PE, Law M, Hwang DH, Boyko OB, Liu CSJ. Predicting Meningioma Consistency on Preoperative Neuroimaging Studies. Neurosurg Clin N Am 2016; 27:145-54. [PMID: 27012379 DOI: 10.1016/j.nec.2015.11.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
This article provides an overview of the neuroimaging literature focused on preoperative prediction of meningioma consistency. A validated, noninvasive neuroimaging method to predict tumor consistency can provide valuable information regarding neurosurgical planning and patient counseling. Most of the neuroimaging literature indicates conventional MRI using T2-weighted imaging may be helpful to predict meningioma consistency; however, further rigorous validation is necessary. Much less is known about advanced MRI techniques, such as diffusion MRI, MR elastography (MRE), and MR spectroscopy. Of these methods, MRE and diffusion tensor imaging appear particularly promising.
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Affiliation(s)
- Mark S Shiroishi
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
| | - Steven Y Cen
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Benita Tamrazi
- Pediatric Neuroradiology, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027, USA
| | - Francesco D'Amore
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Alexander Lerner
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Kevin S King
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Paul E Kim
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Meng Law
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Darryl H Hwang
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Orest B Boyko
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Chia-Shang J Liu
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
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7
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Garcia M, Gloor M, Bieri O, Radue EW, Lieb JM, Cordier D, Stippich C. Imaging of Primary Brain Tumors and Metastases with Fast Quantitative 3-Dimensional Magnetization Transfer. J Neuroimaging 2015; 25:1007-14. [PMID: 25702714 DOI: 10.1111/jon.12222] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 12/04/2014] [Accepted: 12/10/2014] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE This study assesses whether magnetization transfer (MT) imaging provides additive information to conventional MRI in brain tumors. METHODS MT data of 26 patients with neoplastic and metastatic brain tumors were analyzed at 1.5 T. For the 3 largest tumor groups investigated in this study--glioblastoma multiforme (GBM), meningiomas, and metastases-statistical comparisons were performed. Analyzed MT parameters included the magnetization transfer ratio (MTR) and 4 quantitative MT parameters (qMT): Relaxation times (T1, T2), exchange rate (kf), and macromolecular content (F). Total imaging time of high-resolution whole brain MTR and qMT imaging with balanced steady-state free precession required 9 minutes. Five ROIs were chosen: Contrast-enhancing (T1W-CE), noncontrast-enhancing (T1W-non-CE), proximal hyperintensity (T2W-pSI), distal hyperintensity (T2W-dSI), and a reference (ref). RESULTS Pathologies showed significant (P < .05) MT changes (MTR and qMT) compared to the reference. The T1W-CE, T1W-non-CE, and T2W-pSI ROIs of GBMs, meningiomas, and metastases showed significant differences in MTR and qMT estimates. Similar MTR with significant different qMT values were observed in several ROIs among different lesions. MT maps (MTR and qMT) indicated changes in tissue appearing unaffected on MRI in most glial tumors. CONCLUSIONS MTR and qMT imaging enables a better differentiation between brain tumors and provides additive information to MRI.
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Affiliation(s)
- Meritxell Garcia
- Division of Diagnostic & Interventional Neuroradiology, Department of Radiology, Clinic for Radiology & Nuclear Medicine, University of Basel Hospital, Basel, Switzerland
| | - Monika Gloor
- Division of Radiological Physics, Department of Radiology, Clinic for Radiology & Nuclear Medicine, University of Basel Hospital, Basel, Switzerland
| | - Oliver Bieri
- Division of Radiological Physics, Department of Radiology, Clinic for Radiology & Nuclear Medicine, University of Basel Hospital, Basel, Switzerland
| | - Ernst-Wilhelm Radue
- Medical Imaging Analysis Center, University of Basel Hospital, Basel, Switzerland
| | - Johanna M Lieb
- Division of Diagnostic & Interventional Neuroradiology, Department of Radiology, Clinic for Radiology & Nuclear Medicine, University of Basel Hospital, Basel, Switzerland
| | - Dominik Cordier
- Department of Neurosurgery, University of Basel Hospital, Basel, Switzerland
| | - Christoph Stippich
- Division of Diagnostic & Interventional Neuroradiology, Department of Radiology, Clinic for Radiology & Nuclear Medicine, University of Basel Hospital, Basel, Switzerland
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8
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Barker JW, Han PK, Choi SH, Bae KT, Park SH. Investigation of inter-slice magnetization transfer effects as a new method for MTR imaging of the human brain. PLoS One 2015; 10:e0117101. [PMID: 25664938 PMCID: PMC4321840 DOI: 10.1371/journal.pone.0117101] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 12/17/2014] [Indexed: 11/18/2022] Open
Abstract
We present a new method for magnetization transfer (MT) ratio imaging in the brain that requires no separate saturation pulse. Interslice MT effects that are inherent to multi-slice balanced steady-state free precession (bSSFP) imaging were controlled via an interslice delay time to generate MT-weighted (0 s delay) and reference images (5–8 s delay) for MT ratio (MTR) imaging of the brain. The effects of varying flip angle and phase encoding (PE) order were investigated experimentally in normal, healthy subjects. Values of up to ∼50% and ∼40% were observed for white and gray matter MTR. Centric PE showed larger MTR, higher SNR, and better contrast between white and gray matter than linear PE. Simulations of a two-pool model of MT agreed well with in vivo MTR values. Simulations were also used to investigate the effects of varying acquisition parameters, and the effects of varying flip angle, PE steps, and interslice delay are discussed. Lastly, we demonstrated reduced banding with a non-balanced SSFP-FID sequence and showed preliminary results of interslice MTR imaging of meningioma.
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Affiliation(s)
- Jeffrey W. Barker
- Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Paul Kyu Han
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Seung Hong Choi
- Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea
| | - Kyongtae Ty Bae
- Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Sung-Hong Park
- Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
- * E-mail:
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9
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Perez-Torres CJ, Engelbach JA, Cates J, Thotala D, Yuan L, Schmidt RE, Rich KM, Drzymala RE, Ackerman JJH, Garbow JR. Toward distinguishing recurrent tumor from radiation necrosis: DWI and MTC in a Gamma Knife--irradiated mouse glioma model. Int J Radiat Oncol Biol Phys 2014; 90:446-53. [PMID: 25104071 DOI: 10.1016/j.ijrobp.2014.06.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 05/05/2014] [Accepted: 06/04/2014] [Indexed: 11/18/2022]
Abstract
PURPOSE Accurate noninvasive diagnosis is vital for effective treatment planning. Presently, standard anatomical magnetic resonance imaging (MRI) is incapable of differentiating recurring tumor from delayed radiation injury, as both lesions are hyperintense in both postcontrast T1- and T2-weighted images. Further studies are therefore necessary to identify an MRI paradigm that can differentially diagnose these pathologies. Mouse glioma and radiation injury models provide a powerful platform for this purpose. METHODS AND MATERIALS Two MRI contrasts that are widely used in the clinic were chosen for application to a glioma/radiation-injury model: diffusion weighted imaging, from which the apparent diffusion coefficient (ADC) is obtained, and magnetization transfer contrast, from which the magnetization transfer ratio (MTR) is obtained. These metrics were evaluated longitudinally, first in each lesion type alone-glioma versus irradiation - and then in a combined irradiated glioma model. RESULTS MTR was found to be consistently decreased in all lesions compared to nonlesion brain tissue (contralateral hemisphere), with limited specificity between lesion types. In contrast, ADC, though less sensitive to the presence of pathology, was increased in radiation injury and decreased in tumors. In the irradiated glioma model, ADC also increased immediately after irradiation, but decreased as the tumor regrew. CONCLUSIONS ADC is a better metric than MTR for differentiating glioma from radiation injury. However, MTR was more sensitive to both tumor and radiation injury than ADC, suggesting a possible role in detecting lesions that do not enhance strongly on T1-weighted images.
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Affiliation(s)
| | - John A Engelbach
- Department of Radiology, Washington University, St. Louis, Missouri
| | - Jeremy Cates
- Department of Radiation Oncology, Washington University, St. Louis, Missouri
| | - Dinesh Thotala
- Department of Radiation Oncology, Washington University, St. Louis, Missouri
| | - Liya Yuan
- Department of Neurosurgery, Washington University, St. Louis, Missouri
| | - Robert E Schmidt
- Department of Neuropathology, Washington University, St. Louis, Missouri
| | - Keith M Rich
- Department of Radiation Oncology, Washington University, St. Louis, Missouri; Department of Neurosurgery, Washington University, St. Louis, Missouri
| | - Robert E Drzymala
- Department of Radiation Oncology, Washington University, St. Louis, Missouri
| | - Joseph J H Ackerman
- Department of Chemistry, Washington University, St. Louis, Missouri; Department of Radiology, Washington University, St. Louis, Missouri; Department of Internal Medicine, Washington University, St. Louis, Missouri
| | - Joel R Garbow
- Department of Radiology, Washington University, St. Louis, Missouri.
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10
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Scheidegger R, Wong ET, Alsop DC. Contributors to contrast between glioma and brain tissue in chemical exchange saturation transfer sensitive imaging at 3 Tesla. Neuroimage 2014; 99:256-68. [PMID: 24857712 DOI: 10.1016/j.neuroimage.2014.05.036] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 04/30/2014] [Accepted: 05/14/2014] [Indexed: 11/26/2022] Open
Abstract
Off-resonance saturation transfer images have shown intriguing differences in intensity in glioma compared to normal brain tissues. Interpretation of these differences is complicated, however, by the presence of multiple sources of exchanging magnetization including amide, amine, and hydroxyl protons, asymmetric magnetization transfer contrast (MTC) from macromolecules, and various protons with resonances in the aliphatic spectral region. We report a study targeted at separating these components and identifying their relative contributions to contrast in glioma. Off-resonance z-spectra at several saturation powers and durations were obtained from 6 healthy controls and 8 patients with high grade glioma. Results indicate that broad macromolecular MTC in normal brain tissue is responsible for the majority of contrast with glioma. Amide exchange could be detected with lower saturation power than has previously been reported in glioma, but it was a weak signal source with no detectable contrast from normal brain tissue. At higher saturation powers, amine proton exchange was a major contributor to the observed signal but showed no significant difference from normal brain. Robust acquisition strategies that effectively isolate the contributions of broad macromolecular MTC asymmetry from amine exchange were demonstrated that may provide improved contrast between glioma and normal tissue.
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Affiliation(s)
- Rachel Scheidegger
- Harvard-MIT Division of Health Sciences and Technology, 77 Massachusetts Ave E25, Cambridge, MA 02139, USA; Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Ave., Boston, MA 02215, USA.
| | - Eric T Wong
- Brain Tumor Center and Neuro-Oncology Unit, Beth Israel Deaconess Medical Center, 330 Brookline Ave., Boston, MA 02215, USA; Neurology, Harvard Medical School, Boston, MA 02115, USA.
| | - David C Alsop
- Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Ave., Boston, MA 02215, USA; Radiology, Harvard Medical School, Boston, MA 02115, USA.
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11
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Li W, Zhang Z, Nicolai J, Yang GY, Omary RA, Larson AC. Quantitative magnetization transfer MRI of desmoplasia in pancreatic ductal adenocarcinoma xenografts. NMR IN BIOMEDICINE 2013; 26:1688-95. [PMID: 23940016 PMCID: PMC3838498 DOI: 10.1002/nbm.3004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 06/26/2013] [Accepted: 06/27/2013] [Indexed: 05/15/2023]
Abstract
Quantitative assessment of desmoplasia in pancreatic ductal adenocarcinoma (PDAC) may be critical for staging or prediction of response to therapy. We performed quantitative magnetization transfer (qMT) MRI measurements in 18 mouse xenograft tumors generated from three PDAC cell lines. The qMT parameter bound proton fraction (BPF) was found to be significantly higher in tumors grown using the BxPC-3 cell line (5.31 ± 0.87, mean ± standard deviation) compared with the BPF measured for tumors grown from Panc-1 (3.65 ± 0.60) and Capan-1 (1.50 ± 0.58) cell lines (P < 0.05 for each comparison). Histologic measurements demonstrated a similar trend; BxPC-3 tumors had significantly higher fibrosis levels (percentage of fibrotic tissue area, 6.21 ± 2.10) compared with Panc-1 (2.88 ± 1.13) and Capan-1 (1.69 ± 1.01) tumors. BPF was well correlated with quantitative fibrosis levels (r = 0.77, P < 0.01). Our results indicate that qMT measurements offer the potential to noninvasively quantify fibrosis levels in PDAC mouse xenograft models and thus serve as a valuable in vivo biomarker of desmoplasia in PDAC.
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Affiliation(s)
- Weiguo Li
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Zhuoli Zhang
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA
| | - Jodi Nicolai
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Guang-Yu Yang
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA
- Department of Pathology, Northwestern University, Chicago, IL, 60611, USA
| | - Reed A. Omary
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Andrew C. Larson
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA
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12
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Fast high-resolution brain imaging with balanced SSFP: Interpretation of quantitative magnetization transfer towards simple MTR. Neuroimage 2012; 59:202-11. [DOI: 10.1016/j.neuroimage.2011.07.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 07/12/2011] [Indexed: 11/17/2022] Open
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13
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Bell LK, Ainsworth NL, Lee SH, Griffiths JR. MRI & MRS assessment of the role of the tumour microenvironment in response to therapy. NMR IN BIOMEDICINE 2011; 24:612-35. [PMID: 21567513 DOI: 10.1002/nbm.1720] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 02/28/2011] [Accepted: 03/07/2011] [Indexed: 05/30/2023]
Abstract
MRI and MRS techniques are being applied to the characterisation of various aspects of the tumour microenvironment and to the assessment of tumour response to therapy. For example, kinetic parameters describing tumour blood vessel flow and permeability can be derived from dynamic contrast-enhanced MRI data and have been correlated with a positive tumour response to antivascular therapies. The ongoing development and validation of noninvasive, high-resolution anatomical/molecular MR techniques will equip us with the means to detect specific tumour biomarkers early on, and then to monitor the efficacy of cancer treatments efficiently and reliably, all within a clinically relevant time frame. Reliable tumour microenvironment imaging biomarkers will provide obvious advantages by enabling tumour-specific treatment tailoring and potentially improving patient outcome. However, for routine clinical application across many disease types, such imaging biomarkers must be quantitative, robust, reproducible, sufficiently sensitive and cost-effective. These characteristics are all difficult to achieve in practice, but image biomarker development and validation have been greatly facilitated by an increasing number of pertinent preclinical in vivo cancer models. Emphasis must now be placed on discovering whether the preclinical results translate into an improvement in patient care and, therefore, overall survival.
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Affiliation(s)
- Leanne K Bell
- Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
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14
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Zhao X, Wen Z, Huang F, Lu S, Wang X, Hu S, Zu D, Zhou J. Saturation power dependence of amide proton transfer image contrasts in human brain tumors and strokes at 3 T. Magn Reson Med 2011; 66:1033-41. [PMID: 21394783 DOI: 10.1002/mrm.22891] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 01/29/2011] [Accepted: 01/31/2011] [Indexed: 11/10/2022]
Abstract
Amide proton transfer (APT) imaging is capable of detecting mobile cellular proteins and peptides in tumor and monitoring pH effects in stroke, through the saturation transfer between irradiated amide protons and water protons. In this work, four healthy subjects, eight brain tumor patients (four with high-grade glioma, one with lung cancer metastasis, and three with meningioma), and four stroke patients (average 4.3 ± 2.5 days after the onset of the stroke) were scanned at 3 T, using different radiofrequency saturation powers. The APT effect was quantified using the magnetization transfer ratio (MTR) asymmetry at 3.5 ppm with respect to the water resonance. At a saturation power of 2 μT, the measured APT-MRI signal of the normal brain tissue was almost zero, due to the contamination of the negative conventional magnetization transfer ratio asymmetry. This irradiation power caused an optimal hyperintense APT-MRI signal in the tumor and an optimal hypointense signal in the stroke, compared to the normal brain tissue. The results suggest that the saturation power of 2 μT is ideal for APT imaging of these two pathologies at 3 T with the existing clinical hardware.
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15
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Abstract
MRI offers a tremendous armamentarium of different methods that can be employed in brain tumor characterization. MR diffusion imaging has become a widely accepted method to probe for the presence of fluid pools and molecular tissue water mobility. For most clinical applications of diffusion imaging, it is assumed that the diffusion signal vs diffusion weighting factor b decays monoexponentially. Within this framework, the measurement of a single diffusion coefficient in brain tumors permits an approximate categorization of tumor type and, for some tumors, definitive diagnosis. In most brain tumors, when compared with normal brain tissue, the diffusion coefficient is elevated. The presence of peritumoral edema, which also exhibits an elevated diffusion coefficient, often precludes the delineation of the tumor on the basis of diffusion information alone. Serially obtained diffusion data are useful to document and even predict the cellular response to drug or radiation therapy. Diffusion measurements in tissues over an extended range of b factors have clearly shown that the monoparametric description of the MR diffusion signal decay is incomplete. Very high diffusion weighting on clinical systems requires substantial compromise in spatial resolution. However, after suitable analysis, superior separation of malignant brain tumors, peritumoral edema and normal brain tissue can be achieved. These findings are also discussed in the light of tissue-specific differences in membrane structure and the restrictions exerted by membranes on diffusion. Finally, measurement of the directional dependence of diffusion permits the assessment of white matter integrity and dislocation. Such information, particularly in conjunction with advanced post-processing, is considered to be immensely useful for therapy planning. Diffusion imaging, which permits monoexponential analysis and provides directional diffusion information, is performed routinely in brain tumor patients. More advanced methods require improvement in acquisition speed and spatial resolution to gain clinical acceptance.
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Affiliation(s)
- Stephan E Maier
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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16
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MTR variations in normal adult brain structures using balanced steady-state free precession. Neuroradiology 2010; 53:159-67. [DOI: 10.1007/s00234-010-0714-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 04/30/2010] [Indexed: 11/25/2022]
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17
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Zhou J, Blakeley JO, Hua J, Kim M, Laterra J, Pomper MG, van Zijl PCM. Practical data acquisition method for human brain tumor amide proton transfer (APT) imaging. Magn Reson Med 2009; 60:842-9. [PMID: 18816868 DOI: 10.1002/mrm.21712] [Citation(s) in RCA: 270] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Amide proton transfer (APT) imaging is a type of chemical exchange-dependent saturation transfer (CEST) magnetic resonance imaging (MRI) in which amide protons of endogenous mobile proteins and peptides in tissue are detected. Initial studies have shown promising results for distinguishing tumor from surrounding brain in patients, but these data were hampered by magnetic field inhomogeneity and a low signal-to-noise ratio (SNR). Here a practical six-offset APT data acquisition scheme is presented that, together with a separately acquired CEST spectrum, can provide B(0)-inhomogeneity corrected human brain APT images of sufficient SNR within a clinically relevant time frame. Data from nine brain tumor patients at 3T shows that APT intensities were significantly higher in the tumor core, as assigned by gadolinium-enhancement, than in contralateral normal-appearing white matter (CNAWM) in patients with high-grade tumors. Conversely, APT intensities in tumor were indistinguishable from CNAWM in patients with low-grade tumors. In high-grade tumors, regions of increased APT extended outside of the core into peripheral zones, indicating the potential of this technique for more accurate delineation of the heterogeneous areas of brain cancers.
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Affiliation(s)
- Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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18
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Salhotra A, Lal B, Laterra J, Sun PZ, van Zijl PCM, Zhou J. Amide proton transfer imaging of 9L gliosarcoma and human glioblastoma xenografts. NMR IN BIOMEDICINE 2008; 21:489-97. [PMID: 17924591 PMCID: PMC2943209 DOI: 10.1002/nbm.1216] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Amide proton transfer (APT) imaging is a variant of magnetization transfer (MT) imaging, in which the contrast is determined by a change in water intensity due to chemical exchange with saturated amide protons of endogenous mobile proteins and peptides. In this study, eight Fisher 344 rats implanted with 9L gliosarcoma cells and six nude rats implanted with human glioblastoma cells were imaged at 4.7 T. There were increased signal intensities in tumors in the APT-weighted images. The contrast of APT imaging between the tumor and contralateral brain tissue was about 3.9% in water intensity (1.49 +/- 0.66% vs -2.36 +/- 0.19%) for the more uniformly hypercellular 9L brain tumors, and it was reduced to 1.6% (-1.18 +/- 0.60% vs -2.77 +/- 0.42%) for the human glioblastoma xenografts that contained hypocellular zones of necrosis. The preliminary results show that the APT technique at the protein level may provide a unique MRI contrast for the characterization of brain tumors.
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Affiliation(s)
- Amandeep Salhotra
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Neurology, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Bachchu Lal
- Department of Neurology, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - John Laterra
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Neurology, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Phillip Zhe Sun
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Peter C. M. van Zijl
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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Filippi M, Rocca MA. Magnetization transfer magnetic resonance imaging of the brain, spinal cord, and optic nerve. Neurotherapeutics 2007; 4:401-13. [PMID: 17599705 PMCID: PMC7479733 DOI: 10.1016/j.nurt.2007.03.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Magnetic resonance imaging is highly sensitive in revealing CNS abnormalities associated with several neurological conditions, but lacks specificity for their pathological substrates. In addition, MRI does not allow evaluation of the presence and extent of damage in regions that appear normal on conventional MRI sequences and that postmortem studies have shown to be affected by pathology. Quantitative MR-based techniques with increased pathological specificity to the heterogeneous substrates of CNS pathology have the potential to overcome such limitations. Among these techniques, one of the most extensively used for the assessment of CNS disorders is magnetization transfer MRI (MT-MRI). The application of this technique for the assessment of damage in macroscopic lesions, in normal-appearing white and gray matter, and in the spinal cord and optic nerve of patients with several neurological conditions is providing important in vivo information-dramatically improving our understanding of the factors associated with the appearance of clinical symptoms and the accumulation of irreversible disability. MT-MRI also has the potential to contribute to the diagnostic evaluation of several neurological conditions and to improve our ability to monitor treatment efficacy in experimental trials.
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Affiliation(s)
- Massimo Filippi
- Neuroimaging Research Unit, Department of Neurology, Scientific Institute and University Hospital San Raffaele, Milan, Italy.
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Abdullah JM, Farizan A, Asmarina K, Zainuddin N, Ghazali MM, Jaafar H, Isa MN, Naing NN. Association of loss of heterozygosity and PTEN gene abnormalities with paraclinical, clinical modalities and survival time of glioma patients in Malaysia. Asian J Surg 2006; 29:274-82. [PMID: 17098662 DOI: 10.1016/s1015-9584(09)60102-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND The pattern of allelic loss of heterozygosity (LOH) and PTEN mutations appear to be associated with the progression of gliomas leading to a decrement in the survival rate of patients. This present study was carried out to determine the LOH and PTEN mutational status in glioma patients and its association with patients' survival. METHODS Thirty-seven Malaysian glioma patients of the Malay race were subject to PTEN mutational analysis and the presence of LOH using the cold single-strand conformation polymorphism method, and their clinical and paraclinical response were correlated. RESULTS Among analysed glioma patients, seven (21.6%) cases with PTEN mutations were detected and 12 (32.4%) of 37 patients showed presence of LOH. Univariate analysis showed that tumour grade, vascularization, PTEN mutation, LOH and combination of both PTEN mutation and LOH were significantly associated with glioma patients' survival. Multivariate analysis revealed that no factors contributed to survival time. CONCLUSION The results show that PTEN mutation and LOH are quite frequent in Malaysian glioma patients. However, they have no impact on the survival outcome of patients.
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Affiliation(s)
- Jafri Malin Abdullah
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia.
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21
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Pui MH, Wang Y. Diffusion and magnetization transfer MRI of brain infarct, infection, and tumor in children. Clin Imaging 2005; 29:162-71. [PMID: 15855060 DOI: 10.1016/j.clinimag.2004.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2004] [Revised: 07/20/2004] [Indexed: 11/30/2022]
Abstract
The purpose of this study was to determine the efficacy of diffusion-weighted imaging (DWI) and magnetization transfer imaging (MTI) in the differential diagnosis of brain infarct, infection, hamartoma, and tumor in 106 children. The apparent diffusion coefficients (ADCs) and magnetization transfer ratios (MTRs) of the lesions were compared using nonparametric tests. There was an inverse relationship between ADC and MTR in subacute/chronic infarct, infection, hamartoma, arachnoid cyst, and tumor relative to normal brain parenchyma. Both ADC and MTR were reduced in acute infarct. DWI and MTI had a complementary role in the differential diagnosis of acute infarct from infection with lower MTR, from hamartoma with higher ADC, and from low-grade gliomas and benign tumors that had higher ADCs and lower MTRs. ADCs increased and MTRs decreased with the duration of infarct and lower tumor grade.
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Affiliation(s)
- Margaret H Pui
- Department of Radiology, McMaster University Medical Centre, Hamilton, Ontario, Canada L8N 3Z5.
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Filippi M, Rocca MA. Magnetization Transfer Magnetic Resonance Imaging in the Assessment of Neurological Diseases. J Neuroimaging 2004. [DOI: 10.1111/j.1552-6569.2004.tb00255.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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23
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Abstract
Magnetic resonance imaging (MRI) is often divided into structural MRI and functional MRI (fMRI). The former is a widely used imaging technique in research as well as in clinical practice. This review describes the more important developments in structural MRI in recent years, including high resolution imaging, T2 relaxation measurement, T2*-weighted imaging, T1 relaxation measurement, magnetisation transfer imaging, and diffusion imaging. The principles underlying these techniques, as well as their use in research and in clinical practice, will be discussed.
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Affiliation(s)
- M Symms
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, London, UK
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24
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Abstract
Continuous technologic developments and research have increased the clinical applications of MT, HASTE, and FLAIR imaging in neuroradiology. HASTE has become the MR imaging sequence of choice for fetal neuroimaging. Other promising uses, such as for diffusion-weighted imaging, have not been fully exploited. FLAIR has been firmly established as one of the cornerstones of brain imaging; however, post-contrast FLAIR images have not offered a clear advantage over standard T1-weighted images as suggested by early studies. FLAIR imaging with echoplanar acquisition is not considered advantageous, because the decreased imaging times are obtained at the expense of lower sensitivity. For a number of applications, diffusion-weighted imaging has surpassed FLAIR. Nevertheless, FLAIR images may be more sensitive for the detection of acute brain infarction. Recently described methods for the elimination of CSF flow artifacts may lead to improved quality and reliability of FLAIR images for subarachnoid space disease. MT preparation is now routinely incorporated in time-of-flight MR angiography and gradient-echo T2*-weighted spine imaging sequences and provides increased sensitivity for postcontrast MR imaging. These applications may not be advantageous in all clinical settings. MTR analysis offers valuable information for an increasing number of pathologic processes but has not yet gained wide clinical acceptance owing to sophisticated postprocessing and significant intercenter variations. Different modifications of these techniques are being evaluated, and further developments are expected.
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Affiliation(s)
- Zoran Rumboldt
- Department of Radiology, Medical University of South Carolina, 169 Ashley Avenue, Post Office Box 250322, Charlestown, SC 29425, USA.
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Tambasco N, Pelliccioli GP, Chiarini P, Montanari GE, Leone F, Mancini ML, Paciaroni M, Gallai V. Magnetization transfer changes of grey and white matter in Parkinson's disease. Neuroradiology 2003; 45:224-30. [PMID: 12687305 DOI: 10.1007/s00234-002-0925-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2002] [Accepted: 11/25/2002] [Indexed: 11/28/2022]
Abstract
Since the attempt to evidence structural brain damage in Parkinson's disease (PD) by conventional magnetic resonance imaging (MRI) is usually disappointing, we have investigated whether the magnetization transfer ratio (MTR) can reflect changes in grey and white matter of PD patients. MTR was quantified in 44 regions of interest (ROIs) in both grey and white matter of 11 non-demented PD patients, ranging from 2 to 4 on the Hoehn and Yahr Scale, and eight age-matched healthy subjects. MTR differences between patients and controls were found in the supratentorial white matter and in the brainstem. In particular, lower MTR values were found in the paraventricular white matter of PD patients (p<0.05) while no differences were observed in corpus callosum, frontal, parietal, occipital lobes or centrum semiovalis. Lower MTR values were found in substantia nigra (p<0.001), red nucleus (p<0.05) and pons (p<0.05) of the patient group. No differences were discovered in basal ganglia and thalamus. These findings suggest that MTR measurements in the paraventricular white matter and brainstem may help to recognize a marker for probable PD.
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Affiliation(s)
- N Tambasco
- Department of Neuroscience, University of Perugia, via Enrico dal Pozzo, 06126 Perugia, Italy.
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26
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Vahlensieck M, Träber F, Giesecke J, Schild H. [Magnetization transfer contrast (MTC): optimizing off-resonance and on-resonance frequency MTC methods at 0.5 and 1.5 T]. BIOMED ENG-BIOMED TE 2001; 46:10-7. [PMID: 11258135 DOI: 10.1515/bmte.2001.46.1-2.10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIM To compare technical parameters and clinically relevant aspects of on- and off-resonance MTC sequences in mid- and high-field MR systems. MATERIAL AND METHODS Both on- and off-resonance techniques were combined with an FFE sequence using 0.5 and 1.5 Tesla superconducting systems. Parameters were systematically measured by scanning a cadaveric knee joint. Signal-to-noise ratios and MT ratios for fat, cartilage and reference solution (copper sulphate) were determined. Minimal TR and the energy absorption rate were also compared. RESULTS The MT effect at 1.5 T was more pronounced. However, using optimized parameters, clinically adequate MT contrast was achieved with both techniques and both MT units. The most important parameters for the off-resonance method are pulse angle and off-centre frequency; for the on-resonance method, pulse angle and number of composite pulse elements. Energy absorption was below 2 W/kg. Minimal TR was prolonged by up to 400%. CONCLUSION In order to produce MTC images, optimized parameters should be applied. Using optimized pulse parameters, adequate MTC imaging is achievable with mid- and high-field systems using on- and off-resonance techniques. To ensure comparability of MTC studies, the pulse parameters need to be given, and, ideally, standardized.
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