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Investigation of quantitative magnetisation transfer parameters of lesions and normal appearing white matter in multiple sclerosis
Author(s) -
Cercignani M.,
Basile B.,
Spanò B.,
Comanducci G.,
Fasano F.,
Caltagirone C.,
Nocentini U.,
Bozzali M.
Publication year - 2009
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1379
Subject(s) - white matter , magnetization transfer , multiple sclerosis , expanded disability status scale , lesion , magnetic resonance imaging , nuclear magnetic resonance , medicine , pathology , nuclear medicine , physics , radiology , psychiatry
Abstract The aim of this study was to use quantitative magnetisation transfer (MT) imaging to assess the different pathological substrates of tissue damage in multiple sclerosis (MS) and examine whether the MT parameters may be used to explain the disability in relapsing remitting (RR) MS. Thirteen patients with RRMS and 14 healthy controls were prescribed conventional MRI and quantitative MT imaging at 3.0 T. A two‐pool model of MT (where A refers to the free pool and B to the macromolecular pool) was fitted to the data yielding a longitudinal relaxation rate R A , a relative size F of macromolecular pool, transverse relaxation times T 2 Aand T 2 Bfor the two pools and a forward exchange rate RM 0 B . The MT ratio (MTR) was also computed. The mean MT parameters of the normal appearing white matter (NAWM) and of lesions in patients, and of white matter in controls were estimated. MT parameters were significantly different between lesions and NAWM in patients, and between the NAWM and the white matter of controls (with the exception of T 2 Band the MTR). Two models were investigated using ordered logistic regression, with the expanded disability status scale (EDSS) as the dependent variable. In the first one, mean NAWM MT parameters and lesion load were entered as explanatory variables; in the second one, mean MT variables within lesions and lesion load were entered as explanatory variables. Unexpectedly, T 2 Bwas the parameter most significantly associated with EDSS in NAWM. This parameter might represent a weighted average of the relaxation times of spins with different molecular environments, and therefore its variation could indicate a change in the balance between subpopulations of macromolecular spins. Conversely, in lesions, RM 0 B , T 2 B , F , R A , and lesion load significantly predicted disability only when combined together. This might reflect the complex interaction between demyelination, remyelination, gliosis, inflammation and axonal loss taking place within lesions. Copyright © 2009 John Wiley & Sons, Ltd.