The Relationship Between Multiple Sclerosis and Middle Cerebellar Peduncle Lesions: An Exploratory Study
Lesioned middle cerebellar peduncles (MCPs) have been hypothesized to impair information transfer to the cerebellum in multiple sclerosis (MS) patients, and have been associated with MS clinical impairment.
The goals of this study are twofold: (1) To determine the prevalence of MCP lesions in MS patients (2) To examine the prevalence of MS in patients with MCP lesions, regardless of diagnosis.
1. Retrospective chart review of patients at Loyola University Medical Center (LUMC) with a diagnosis of MS of any type between 2010 and 2014. Radiological reports and physician reports were primarily used to determine whether an MCP lesion was present at any given encounter. If no MCP lesion was reported, T2-weighted MRI was first reviewed by a medical student for focal hyperintensivities. Secondary review of potential MCP lesions identified by the medical student was done by the attending neurologist.
2. Retrospective chart review of patients with any intrinsic MCP lesion recorded in radiological reports of MRI or CT imaging between 2007 and 2015. Patients were excluded if pathology was due to mass effect from adjacent tumor.
1. 109 MS patients met our study criteria. Of these patients, 74.1% were female. The mean age at MS diagnosis was 34.5 years (range 17-62 years). The patients’ MS lesions were classified into three localized regions: juxtacortical, periventricular, and infratentorial. Periventricular lesions were most common (97.2%), followed by juxtacortical (89.9%) and infratentorial (75.2%). Three-quarters (73.2%) of patients with infratentorial lesions possessed MCP lesions, either isolated or in combination with cerebellar and/or brainstem lesions. Over half (55%) of total patients possessed an MCP lesion.
2. 142 patients had radiographic evidence of damage to the MCP. Of these patients, 58.4% were female. The mean age at the initial appearance of the MCP lesion was 54.6 years (range 6-97 years.) MS accounted for 37.3% of lesions. Vascular pathology accounted for 26.8% of lesions, over half of which were related to chronic ischemic changes (52.6%). Among other etiologies, metastatic disease and cavernous malformation were most common (43.1% combined.)
To our knowledge, the data about estimated prevalence of MCP lesions in MS are lacking. According to our analysis, 55% of patients in this MS sample were found to have an MCP lesion. Conversely, in a sample of patients with MCP lesions, regardless of diagnosis, 37.3% of lesions were attributed to MS, although the mean age at the initial appearance of an MCP lesion was 20 years above the mean age at MS diagnosis. Given the disability that may be associated with MCP lesions in MS patients, more investigation into their prevalence and clinical significance in this population is warranted.