MR imaged neurovascular relationships at the cerebellopontine angle

Improvements in MR imaging techniques allow visualisation of the anatomy of the cerebellopontine angle (CPA) in increasingly accurate detail, revealing the complex interrelationship of the neurovascular structures in this region. We wished to assess whether vessels and vascular loops intimately associated with cranial nerves VII and VIII, corresponded to any abnormality or symptom pattern, and thus had any clinical significance. The MR scans of 108 patients were retrospectively reviewed and the imaging status of VII, VIII, the vessels, presence of vascular loops and their relationship to the nerves, coded and recorded. The patients' records were independently reviewed and the presence and "sidedness' of asymmetrical hearing loss, tinnitus, vertigo, and the results of caloric and brain stem evoked responses recorded. The vessels were closely associated with VII and VIII in over 30% of this sample with vascular loops imaged in 21% of patients, and clearly imaged entering the IAM in 7% of both right and left CPAs studied. There was no statistically significant relationship demonstrated between the proximity of the vessels, or vascular loops, to the nerves and a symptom, or symptom pattern. These findings should be considered a normal variant on MR scanning.