Analysis of multiple sclerosis lesions using a fusion of 3.0 T FLAIR and 7.0 T SWI phase: FLAIR SWI

Abstract

To improve multiple sclerosis (MS) research by introducing a new type of contrast, namely, the combination of fluid-attenuated inversion recovery (FLAIR) data acquired at 3.0 T and 7.0 T susceptibility-weighted imaging (SWI) phase data. The approach of this new contrast is whole-brain coverage with 3.0 T-FLAIR data for lesion detection--currently limited at 7.0 T due to specific absorption rate (SAR) limits--overlaid with high-resolution, small vessel, and iron-related 7.0 T SWI contrast. Lesion analysis in terms of penetrating veins and local iron depositions were performed. Data from 10 MS patients were acquired at 3.0 T and at 7.0 T. FLAIR data, acquired at 3.0 T, were registered to 7.0 T SWI phase data and SWI image processing was performed using 3.0 T FLAIR data instead of SWI magnitude data. A total of 299 MS plaques were detected in eight MS patients. Penetrating veins were found in 75 MS plaques, iron depositions in 48 MS plaques, and veins accompanied with iron depositions in 44 MS plaques. FLAIR-SWI provides radiologically known, hyperintense definition of MS lesions overlaid with high-resolution visualization of iron deposits and venous blood vessels and offers new insights into MS lesions.