Assessment of Normal-Appearing White Matter Damage in Multiple Sclerosis Using Diffusion Tensor Imaging

Abstract

Purpose: To determine any evidence of damage in normal-appearing white matter (NAWM) tracts in multiple sclerosis (MS) cases using diffusion tensor imaging (DTI). Materials and Methods: We retrospectively analyzed anisotropy maps derived from DTI studies performed in 16 MS patients and 14 normal controls. Fractional anisotropy (FA) was measured in NAWM tracts: in the genu and splenium of the corpus callosum and at three points along the corticospinal tracts (internal capsule, cerebral peduncle, and pons). In addition, we performed lesion loads using the manual tracing method in the anterior, posterior, corona radiata, and supratentorial of each side. A FA in NAWM tracts was compared between patients and normal controls using the Student t-test. The FA values and lesion load were compared by performing a Spearman rank correlation. Results: The mean FA values were lower in patients than the controls for the combined genu and splenium (p