Normal-appearing white matter changes vary with distance to lesions in Multiple Sclerosis
Vrenken H, Geurts J, Barkhof F, Knol D, Polman C, Castelijns J, Pouwels P
VU University Medical Center, VU University Medical Center
Goal: To investigate the relation of normal-appearing white matter (NAWM) changes in Multiple Sclerosis (MS) with the lesions visible on conventional MR.Methods: We measured whole-brain, B1-corrected T1 relaxation time and magnetization transfer ratio (MTR) maps in MS patients and healthy controls. Histograms of T1 and MTR were analyzed for NAWM pixel subsets progressively further from the MR visible lesions.Results: While MTR histogram abnormalities were confined to the first two pixel layers around lesions, T1 histogram abnormalities were more widespread. NAWM distant from lesions had T1 histograms significantly different from control white matter, while MTR histograms were normal.