A one year follow up study with monthly gadolinium enhanced MRI: Correlations with changes of T2 and magnetization transfer lesion loads

In this study, we assessed the correlation between the frequency and extent of gadolinium enhancement detected by monthly enhanced magnetic resonance imaging (MRI) scans with yearly changes of lesion load on T2-weighted and calculated magnetization transfer (MT) scans in seven patients with relapsing-remitting and seven patients with secondary progressive multiple sclerosis (MS). For the whole patient sample, anc' for relapsing-remitting patients only, the monthly number and volume of enhancing lesions showed no significant correlation with the yearly changes of lesion volumes on T2 and calculated MT images. However, strong correlations were found between the monthly number and volume of gadolinium enhancing lesions with changes of T2 (r=0.93, p=0.02) and MT (r=0.82, p=0.04) lesion loads in patients with secondary progressive MS. Strong correlations were also found between the lesion loads on T2weighted scans and on calculated MT images both at entry and exit (r=0.83, p=0.003). The yearly changes of lesion loads detected by the two techniques were also moderately correlated (r=0.51,p=0.05). This study provides further evidence that the MS pathological process is different in relapsing-remitting and secondary progressive MS. It also suggests that the effectiveness of recovery mechanisms within lesions might be one of the major factors responsible for such a difference.