title: Normal-appearing white matter in multiple sclerosis has heterogeneous, diffusely prolonged T(2).
abstract: T(2) relaxation in normal-appearing white matter (NAWM) of multiple sclerosis (MS) patients was reexamined using more complete sampling and analysis of decay curves, and to assess focal vs. diffuse abnormalities. Nine MS patients and 10 controls were scanned using a single-slice 32-echo pulse sequence with a 10-ms echo spacing. Decay curves from outlined white and gray matter structures were analyzed using non-negative least-squares (NNLS). Resulting T(2) distributions were each summarized by the geometric mean T(2), T(2). Different white matter structures had different mean (over the subjects in a group) T(2). Mean T(2) in NAWM was always greater than that of controls. Differences were not caused by a few voxels with extreme T(2) (i.e., focal lesions), but rather by shifts of the entire T(2) distribution (diffuse prolongation). This T(2) increase suggests diffuse myelin or axonal pathology.
authors.affiliation: Department of Radiology, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Whittall
authors.forename: Alex L
authors.initials: AL
authors.lastname: MacKay
authors.forename: David K B
authors.initials: DK
authors.lastname: Li
authors.forename: Irene M
authors.initials: IM
authors.lastname: Vavasour
authors.forename: Craig K
authors.initials: CK
authors.lastname: Jones
authors.forename: Donald W
authors.initials: DW
authors.lastname: Paty
mesh_terms: D000328:Adult; D001369:Axons / Q000473:pathology; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020528:Multiple Sclerosis, Chronic Progressive / Q000175:diagnosis*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis*; D009186:Myelin Sheath / Q000473:pathology; D012680:Sensitivity and Specificity