Re-evaluation of arterial dissection as a possible major cause of lateral medullary infarction in a single-center study from South Korea.

Limited sensitivity of conventional MRI and the invasiveness of TFCA have restricted the diagnosis of arterial dissection in lateral medullary infarction (LMI), leading to its underestimation and obscuring its clinical significance. However, high-resolution vessel wall MRI (HR-VWMRI) now allows more accessible and accurate diagnosis of dissection, prompting reevaluation of its prevalence. This single-center retrospective study included the LMI patients, among whom a subset underwent advanced imaging as HR-VWMRI or TFCA to confirm definite arterial dissection, and identified clinical factors associated with dissection. A risk scoring system for dissection was then developed based on these factors, and possible dissection was defined using the optimal cutoff value. Among 87 LMI patients, 47 underwent advanced imaging, with 24 (51.1%) diagnosed with definite dissection. Younger age, lower body mass index, headache, and absence of hypertension were associated with definite dissection and constructed dissection score, which showed 87.5% sensitivity and 73.9% specificity. Among the remaining 38 without advanced imaging, 12 were classified as possible dissection. Definite and possible dissections collectively accounted for 43.7% of LMI, exceeding large-artery atherosclerosis. These findings suggest dissection may be a predominant cause of LMI, underscoring the need for heightened awareness in clinical practice and proactive, risk-stratified diagnosis of arterial dissection.