Clinical Relevance of New and Enlarging Lesion Volume in Relapsing Remitting Multiple Sclerosis: A Multi-Center Study
Brain Magnetic Resonance imaging (MRI) has shown its effectiveness in multiple sclerosis (MS) for diagnosis, monitoring, prognosis and assessment of drug efficacy. Several MRI biomarkers have been explored such as total lesion volume, T1 black holes, whole brain atrophy etc.
We investigate the role of new and enlarging lesion (NEL) volume in monitoring Relapsing-Remitting MS (RRMS) disease activity. In particular, we explore the relationship between the new and enlarging lesion volume and Expanded Disability Status Scale (EDSS) score, both on a group level and on an individual patient level using multi-center data. We used MSmetrix to measure NEL volume.
Dataset 1 contains scans from 30 RRMS patients acquired on a SIEMENS 1.5T with at least 3 time points that are either 6 or 12 months apart. Dataset 2 contains scans from 20 RRMS patients acquired on a GE 3T scanner, at 2 time points one year apart. Dataset 3 contains scans from 35 RRMS patients acquired on a Philips 3T scanner, each scanned at least twice at a variable time interval ranging from 4 to 12 months.
Each scan contains a 3D T1-weighted and 3D or 2D FLAIR sequence. EDSS scores were available for all subjects.
At group level, the correlation between EDSS change (difference between the last and the first EDSS score) and NEL volume is investigated using Pearson correlation coefficient. At subject level, the trend of EDSS score and NEL volume is examined over time. An enlarging lesion is defined as a lesion of which the overall volume is increased by more than 5% compared to the previous time point.
At a group level, the correlation between EDSS change and NEL volume is low (dataset 1 r=0.09, dataset 2 r=0.12, dataset 3 r=0.14); however this correlation increases when the values from all three datasets are included simultaneously in the analysis (r=0.17). At subject level, the following trends are observed. First, with an increase in the NEL volume, the EDSS score is increased either at the current time point or in the near future time point. And second, with a decrease in the NEL volume, the EDSS score is either decreased or remains nearly the same.
This study showed interesting trends in the data, suggesting that the knowledge about NEL volume may predict how the EDSS score will evolve over time; however an extensive further validation is required.