Neurology and Neurosurgery Resident The Ohio State University College of Veterinary Medicine Grandview Heights, OH, United States
Abstract:
Background: Changes in T2-weighted (T2W) MRI signal intensity of paraspinal musculature can serve as an imaging biomarker in amyotrophic lateral sclerosis (ALS) and may reflect intramuscular fat accumulation or edema. Given disease similarities to canine degenerative myelopathy (DM), exploration of this phenomenon in DM is warranted. Hypothesis: Dogs with DM will demonstrate increased T2 signal intensity in the paraspinal musculature compared to controls. Animals: Dogs previously imaged by MRI; autopsy confirmed with DM (7) and controls (6).
Methods: Retrospective, blinded, single observer, pilot investigation using images acquired on a 3.0 T scanner. Spinal cord diameter and T2 signal intensity of longissimus (l.) thoracis (T8) and l. lumborum (L1) were measured in a sagittal plane. Triplicate measurements assessed intra-rater agreement. Data were expressed as median (range). Wilcoxon rank sum tests compared signalment data and muscle T2 signal intensity between groups, p
Results: There were no significant group differences in age, weight, or adiposity (Table 1). ICC was excellent for all MRI measurements (r > 0.94). Spinal cord diameter (mm) at T13 was smaller (p=0.035) in DM-affected dogs (3.7; 3.4-4.5) than controls (4.4; 3.9-4.9). Muscle T2 signal intensity was higher in DM-affected dogs compared to controls at all sites, but when scaled to background signal significance remained only in the right l. lumborum (Table 2).Conclusions and Clinical Importance: These findings invite investigation in a larger cohort to confirm true differences in DM-affected dogs, expand muscle measurements to additional imaging planes, and correlate with disease severity.
