Pattern of hemodynamic impairment in multiple sclerosis: dynamic susceptibility contrast perfusion MR imaging at 3.0 T

Abstract

This study aimed to determine regional pattern of tissue perfusion in the normal-appearing white matter (NAWM) of patients with primary-progressive (PP), relapsing-remitting (RR) multiple sclerosis (MS) and healthy controls, and to investigate the association between perfusion abnormalities and clinical disability. Using dynamic susceptibility contrast (DSC) perfusion MRI at 3 T, we studied 22 patients with clinically definite MS, 11 with PP-MS and 11 with RR-MS and 11 age- and gender-matched healthy volunteers. The MRI protocol included axial dual-echo, dynamic susceptibility contrast enhanced (DSC) T2*-weighted and post-contrast T1-weighted images. Absolute cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) were measured in the periventricular, frontal, occipital NAWM and in the splenium of the corpus callosum. Compared to controls, CBF and CBV were significantly lower in all NAWM regions in both PP-MS patients (p values from <0.0001 to 0.001) and RR-MS (p values from <0.0001 to 0.020). Compared to RR-MS, PP-MS patients showed significantly lower CBF in the periventricular NAWM (p=0.002) and lower CBV in the periventricular and frontal NAWM (p values: 0.0029 and 0.022). EDSS was significantly correlated with the periventricular CBF (r=-0.48, p=0.0016) and with the periventricular and frontal CBV (r=-0.42, p=0.015; r=-0.35, p=0.038, respectively). This study suggests that the hemodynamic abnormalities of NAWM have clinical relevance in patients with MS. DSC perfusion MRI might provide a relevant objective measure of disease activity and treatment efficacy.

Fig. 1

Top: Axial gradient-echo echo-planar MR image from a healthy control (a), a RR-MS patient (b) and a PP-MS patient (c). Bottom: Axial gradient-echo echo-planar MR image from the same healthy control (d), a RR-MS patient (e) and a PP-MS patient (f) with CBF color-coded map overlay. The color bar indicates the CBF values (ml/100gr/min). Note generally lower CBF values on the color-coded map of the patient with PP-MS.

Fig. 2

Top: Box plots display the 25%–75% values (boxes) ± 95% values (whiskers), median values (horizontal lines within boxes), and outliers (*) of absolute CBF value distribution in regions of frontal, periventricular, occipital NAWM and splenium of the corpus callosum among patients with PP-MS (hatched box), with RR-MS (crosshatched box) and in healthy controls (empty box). Bottom: Box plots display the 25%–75% values (boxes) ± 95% values (whiskers), median values (horizontal lines within boxes), and outliers (*) of absolute CBV value distribution in regions of frontal, periventricular, occipital NAWM and splenium of the corpus callosum between patients with PP-MS (hatched box), with RR-MS (crosshatched box) and in healthy controls (empty box). Only significant p values are reported. Note that the median CBF and CBV values in PP-MS patients are lower than those in RR-MS patients, which in turn, are lower than those in controls.