How accurately can a scan detect blood-vessel compression of the trigeminal nerve before surgery?

Details

The study investigated whether preoperative imaging could identify neurovascular compression in 92 patients with trigeminal neuralgia (TGN) before posterior fossa surgery. Patients underwent magnetic resonance imaging (MRI) and contrast-enhanced magnetic resonance angiography (MRA). The preoperative imaging assessment was assigned to one consultant neuroradiologist, a study co-author, who was blinded to the side of the patients’ symptoms. In this diagnostic accuracy comparison, imaging results were compared with operative findings in all 92 patients.

In 76 patients, MRA showed neurovascular compression that was confirmed during surgery. In eight cases, neither MRA nor surgery showed compression. Another eight cases were incorrectly predicted by MRA to have no compression; there were no false-positive predictions. Using operative findings as the reference, MRA had a sensitivity of 90.5% and a specificity of 100%.

MRA predicted compression of the trigeminal nerves on both sides in 19 cases. Only two cases had clinically bilateral TGN.

The authors concluded that gadolinium-enhanced MRA was an extremely sensitive and specific method for demonstrating compression in TGN. On this basis, they stated that posterior fossa surgery could be recommended with confidence, and that microvascular decompression remained the treatment of choice for TGN at their centre.