Magnetic resonance imaging derived biomarkers in multiple sclerosis
Date
2007
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Several mechanisms contribute to the complex pathophysiology of multiple sclerosis (MS). This calls for biomarkers to characterize the heterogeneity of MS in individual subjects. The advancement in magnetic resonance imaging (MRI) technology over past decades makes it the most attractive biomarker candidate in MS. Texture analysis was applied to quantify subtle abnormalities on the MRI from people with MS. A classical statistical method (gray level co-occurrence matrix) was able to detect a tread yet not significant difference of therapeutic responses between different tissue types. A novel time-frequency based technique (polar Stockwell Transform, PST) was then investigated. The increased PST texture was shown to represent inflammation and demyelination in a murine model of MS. PST texture altered significantly when tissue MRI evolved from normal appearing white matter to MS lesions. It decreased significantly when an active lesion became inactive. This suggests that the PST texture may be a MRI surrogate to characterize subtle and early abnormalities existed in MS tissue. MS is also a neurodegenerative disease in the central nervous system (CNS) affecting both white matter and grey matter (GM). Abnormally decreased signal intensity (black T2, BT2) in the deep GM of MS patients was noted on 1.5 T MRI. Due to the iron deposition phenomenon in its underlying tissue, 3 T MRI was more sensitive to BT2 detection than 1.5 T MRI. A higher correlation was obtained between patient disability and deep GM BT2 measured at 3 T than that at 1.5 T in MS. The association of 3 T BT2 with EDSS was greater than most of the MRI derived indices in MS. The small sample size limits broad conclusions. However, these results encourage further investigation of the clinical significance of BT2 as a biomarker for disability in MS at high field. This thesis provides evidence for proof of concept that the new developed techniques may have potential to become surrogate measures in MS diagnostics and treatment. However, these techniques need to be combined with other MRI matrices in order to obtain an integrated picture of MS.
Description
Bibliography: p. 143-172
Keywords
Citation
Zhang, Y. (2007). Magnetic resonance imaging derived biomarkers in multiple sclerosis (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/1033