Abstract #3: Converting from CIS to Definite Multiple Sclerosis: An Imaging Based Predictive Model

Abstract

Objective To quantitatively assess brain parenchymal fraction (BPF), gray matter (GM) atrophy, and white matter (WM) lesion load and to determine their association with the likelihood of CIS patients to convert to definite multiple sclerosis (MS) over time. Background Patients with clinically isolated syndromes (CIS) are those presenting a first neurologic episode suggestive of MS. A better understanding of the different biomarkers of brain damage in the early stages of MS and their association to clinical progression are essential so that treatments designed to limit or delay tissue damage may be initiated. Methods This is a retrospective study of baseline MRI examinations obtained from 12 CIS patients. Eight out of the 12 patients converted to definite MS within 5 years. Demographic characteristics of the patients who converted and did not convert (mean ± SD) were: age converters = 31.3 ± 8.6 and age non-converters = 27.7 ± 5.2. Brain MR images were processed by an experienced observer using both semi-automated and manual techniques in order to estimate BPF, thalamus, putamen, caudate, and globus pallidus volumes, as well as PD/T2-weighted, T1-weighted, and Gd-T1w lesion volumes. Comparisons between converters and non-converters were based on a Wilcoxon rank sum test. The predictive value of each variable was investigated using a logistic regression. Results In those patients who converted, BPF was significantly lower than in those who did not convert (0.761 ± 0.034 vs. 0.812 ± 0.016; p = 0.008). BPF was a perfect discriminator between converters and non-converters. All patients with a BPF > 0.795 did not convert and all patients with a BPF < 0.795 converted. We continue to accumulate additional patients for analysis to extend and confirm these findings. Conclusions In this preliminary study we found an association between BPF and the likelihood of CIS patients to convert to definite MS. These finding implicate brain atrophy present in the early stages of the disease as playing a role in further disease progression. Support This study was supported by research grants from the National Institutes of Health (1R01NS055083-01) and the National Multiple Sclerosis Society (RG4032A1/1, RG3705A1; RG3798A2).