Abstract
On the basis of the fact that 92% of the cases with hemifacial spasm caused by neurovascular compression (NVC) at the root entry zone of the facial nerve have dolichoectatic ipsilateral convexity of the basilar artery (BA) on a MR image (MRI), 37 of 40 vertiginous patients suspected as due to NVC were evaluated with T2-weighted MRI.MRI of 18 patients with sudden deafness or vestibular neuronitis were used as controls. The displacement and distance of the cross section of BA from the midline were assessed at the level of the internal auditory meatus in the axial view. The displacement was ipsilateral to the affected side in 32 (86.5%), contralateral in 4 (10.8%) and not recognized in one (2.5%) of 37 patients, whereas it was ipsilateral to the lesion in 4 (22.2%), contralateral in 7 (38.9%) and not recognized in 7 (38.9%) of 18 controls. The mean distance in 33 of 37 patients and 17 of 18 controls was 5.7 mm (0-11.8 mm) and 2.9 mm (0-8.9), respectively.
These results showed that the ipsliateral convexity of BA in vertiginous patients suspected as due to NVC was significantly more severe and seen at a significantly high incidence. The ipsilateral displacement of BA on the axial view of MRI has been suggested to serve as a diagnosis of vertigo due to NVC.
