Relationship between neurological asymptomatic vertigo and the vertebrobasilar system as revealed by magnetic resonance angiography.
Many patients suffering from vertigo have no neurological symptoms except for a positional nystagmus. Vertigo without any neurological findings has not been thought to be a vertebrobasilar (VB) attack. The purpose of this study is to clarify the relationship between vertigo without any neurological symptoms and the VB system using magnetic resonance angiography (MRA). MRAs of the VB system were examined in 31 patients with positional nystagmus of unknown origin (PNU) and in 14 patients with benign paroxysmal positional vertigo (BPPV) as control. MRA was performed with a 1.5-tesla system using the two-dimensional time-of-flight technique. Abnormalities such as elongation, bending, narrowing or obstruction of the artery were detected in 27 patients of the PNU group and 8 patients of the BPPV group. A significant difference in the abnormalities was noticed between the two groups (p < 0.05; chi(2) test). This result is almost similar to those of previous studies using conventional vertebral angiography and digital subtraction angiography. Thus, MRA is useful in examination of the VB system. Moreover, our study suggested that the positional nystagmus might result from VB ischemia, even if there were no other neurological signs.