Imaging studies of two cases of trigeminal neuralgia caused by a dolichoectatic vertebrobasilar system

Two men with trigeminal neuralgia caused by trigeminal nerve compression from the dolichoectatic basilar and vertebral arteries were diagnosed, one by CTA (computed tomographic angiography) and the other by MRA (magnetic resonance angiography). In one case, CTA showed marked ectatic vertebrobasilar arteries, which deviated to the right cerebellopontine angle with compression of the right fifth nerve. In the second case, the root entry zone (REZ) of the left fifth cranial nerve compressed by the left tortuous, dolichoectatic vertebral artery and the left posterior inferior cerebellar artery (PICA) was demonstrated on MRI together with reconstructed MRA. In a patient with trigeminal neuralgia, MRI combined with reconstructed MRA provides a satisfactory preoperative diagnosis by showing the course of the pathologic vessels and the precise anatomic relationship between the causative vessels and the compressed trigeminal nerve, and by excluding other etiologies such as tumors, epidermoid cysts, arachnoid cysts and multiple sclerosis.