Longitudinal assessment of spinal cord injuries in nonhuman primates with quantitative magnetization transfer

• Published in: Magnetic resonance in medicine Vol. 75; no. 4; pp. 1685 - 1696
• Main Authors: Wang, Feng, Li, Ke, Mishra, Arabinda, Gochberg, Daniel, Min Chen, Li, Gore, John C.
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.04.2016; Wiley Subscription Services, Inc
• Subjects: 9.4T; Animals; Anisotropy; Brain - diagnostic imaging; Brain - pathology; cyst; Cysts; Demyelinating Diseases - diagnostic imaging; Demyelination; Diffusion coefficient; Diffusion rate; Image Processing, Computer-Assisted - methods; Injuries; Lesions; Macromolecules; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Magnetization; Male; MRI; Parameter robustness; quantitative magnetization transfer (qMT); Reproducibility; Saimiri; Spinal cord injuries; Spinal Cord Injuries - diagnostic imaging; Spinal Cord Injuries - pathology; spinal cord injury; Substantia alba; Substantia grisea; spinal cord injury; cyst; quantitative magnetization transfer (qMT); MRI; demyelination; 9.4T
• ISSN: 0740-3194; 1522-2594; 1522-2594
• DOI: 10.1002/mrm.25725

Purpose This study aimed to evaluate the reproducibility and specificity of quantitative magnetization transfer (qMT) imaging for monitoring spinal cord injuries (SCIs). Methods MRI scans were performed in anesthetized monkeys at 9.4T, before and serially after a unilateral lesion of the cervical spinal cord. A two‐pool fitting model was used to derive qMT parameters. Results qMT measures were reproducible across normal subjects, with an average pool size ratio (PSR) of 0.086 ± 0.003 (mean ± SD) for gray matter, and 0.120 ± 0.005 for white matter, respectively. Compared with normal gray matter, the PSR of abnormal tissues rostral and caudal to the injury site decreased by 19.5% (P < 0.05), while the PSR of the cyst‐like volume decreased drastically weeks after SCI. Strong correlations in cyst‐like regions were observed between PSR and other MRI measures including longitudinal relaxation rate (R1), apparent diffusion coefficient and fractional anisotropy (FA). Decreased PSR and FA values correlated well with demyelination in abnormal tissues. Conclusion The qMT parameters provide robust and specific information about the molecular and cellular changes produced by SCI. PSR detected demyelination and loss of macromolecules in abnormal tissue regions rostral and caudal to the cyst/lesion sites. Magn Reson Med 75:1685–1696, 2016. © 2015 Wiley Periodicals, Inc.