Selective Application of High-Resolution 3 T MRI in the Evaluation of Intracranial Vertebral Artery Dissection

BACKGROUND AND PURPOSE: Although high-resolution magnetic resonance imaging (HR-MRI) is considered optimal for the diagnosis of intracranial vertebral artery dissection (IVAD), it is not readily available for all patients with suspected IVAD. The purpose of our study was to determine the factor related to IVAD lesions that are not definitively diagnosed by conventional MRI. METHODS: This study included IVAD lesions that were evaluated with both of 3 T conventional MRI and HR-MRI. Definitive dissection was defined as the presence of one or more pathognomonic radiological findings including crescentic intramural hematoma, intimal flap, and double lumen. A total of 30 IVAD lesions definitively diagnosed by HR-MRI were included and grouped into a conventional MRI true-positive group (n = 17) or false-negative group (n = 13) based on the presence of definitive findings on conventional MRI. RESULTS: Clinical characteristics did not differ between the two groups. The absence of vertebral artery aneurysmal dilatation was more common in the conventional MRI false-negative group (84.6% vs. 35.3%; P = .010). Ipsilesional vertebral hypoplasia was observed more frequently in the conventional MRI false-negative IVAD group (53.8% vs. 17.6%; P = .056). In logistic regression, absence of vertebral artery aneurysmal dilatation was independently associated with conventional MRI false-negative IVAD (OR, 16.37; 95% CI, 1.39-192.30; P = .026). Ipsilesional vertebral artery hypoplasia showed only a trend as a predictor of conventional MRI false-negative IVAD (OR, 7.24; 95% CI,.73-71.51; P = 0.090). CONCLUSIONS: HR-MRI may be useful for diagnosing IVAD without aneurysmal dilatation or with ipsilesional vertebral hypoplasia.