Multislice Brain Myelin Water Fractions at 3T in Multiple Sclerosis

Abstract

To evaluate a multislice nonlinearly-spaced 12-echo imaging sequence at 3T covering the supratentorial brain for the quantification of myelin water fraction (MWF) in multiple sclerosis (MS) patients. Eighty-nine patients with, or at risk of, MS (69 relapsing remitting MS [RRMS], 7 secondary progressive MS [SPMS], 13 clinically isolated syndrome [CIS]) and 28 controls were studied. Twelve-echo datasets were acquired using a multislice T2 prep spiral imaging sequence and were fitted using a nonnegative least squares algorithm. The mean MWF within normal appearing white matter (NAWM), contrast-enhancing (CE), and nonenhancing T2 lesions were calculated. Mean MWF in white matter for controls was 11.3%. Mean MWF was significantly reduced in NAWM of MS patients (10.6%, P= .004) relative to controls. SPMS/RRMS patients with disease duration >5 years (10.3%) had lower MWF compared to CIS/RRMS with disease duration <or=5 years (10.8%, P= .03). Mean MWF was reduced by 26% and 29% within both CE (P < .0001) and nonenhancing T2 lesions (P < .0001) relative to controls. Using a multicomponent T2 sequence at 3T, a significant decrease in the supratentorial MWF was observed in MS NAWM and lesions relative to controls. The method was sensitive to detect white matter changes early in the disease process.