Relationship between MRI Reported Lesion Location with Gait Speed and Disability Status in Multiple Sclerosis

Background: Magnetic Resonance Imaging can reveal CNS lesions in patients with Multiple Sclerosis (pwMS). MRI reports written by radiologists are a time-efficient, easily accessible source of MRI results for clinicians. These results are often used in clinical decision-making and disease monitoring. It is therefore important to understand how lesions noted on MRI reports correlate with clinical symptoms. Two clinical tools used to quantify and monitor disability in pwMS are the timed 25-Foot Walk (T25FW) and the Kurtzke Expanded Disability Status Scale (EDSS).

Objectives: The objectives of this study are 1) to understand the distribution of lesion locations in pwMS available to clinicians via MRI reports at a community MS center, and 2) to evaluate the relationship between MRI reported lesion location with mobility and disability in pwMS.

Methods: This was a retrospective chart review. Of 216 pwMS recruited into a larger study, 82 met study criteria and were analyzed. Each subject included had a MRI of the brain and spine within ± 6 months of an assessment of T25FW and EDSS. During MRI review, lesion location was recorded and categorized into four broader regions: Infratentorial/Cerebellar, Juxtacortical, Periventricular, and Spinal Cord. Analysis was performed to determine if a relationship exists between number of lesion areas and EDSS/T25FW score. A Kruskal-Wallis test was used to determine differences in EDSS and T25FW scores, and multiple linear regressions to examine the effects of each of the four brain lesion areas on T25FW and EDSS. P<0.05 was considered significant.

Results: Lesions were most frequent in the periventricular region (n=73; 89%) and least frequent in the infratentorial/cerebellar region (n=29; 35%). No significant relationship was observed between number of CNS regions with lesions and either T25FW (p=0.502) or EDSS (p=0.719). Multiple linear regression showed the presence of a lesion in the intratentorial/cerebellar region had a significant positive relationship with having a slower walking speed (B=3.012 seconds, p=0.019). Multiple linear regression showed no significant relationship between lesions in any of the four CNS regions with EDSS.

Conclusions: Categorizing specific lesions identified into four regions provided a format for systematizing data reported to clinicians on MRI reports. Lesions in the infratentorial/cerebellar region had a significant relationship with walking speed. Number of CNS regions with lesions was not associated with walking speed or disability status.