SENSITIVITY AND SPECIFICITY OF MRA IN THE DIAGNOSIS OF NEUROVASCULAR COMPRESSION IN PATIENTS WITH TRIGEMINAL NEURALGIA - A CORRELATION OF MRA AND SURGICAL FINDINGS

The published rates of operatively confirmed neurovascular compression as the cause for trigeminal neuralgia range from 10% to nearly 100 %. High-definition magnetic resonance angiography (MRA) was performed in 27 consecutive patients (in 6 casts with 3D reconstructions) to show neurovascular compression preoperatively. The MRA findings were compar ed with the relationship between the Vth nerve and the surrounding ves sels at surgery. In 23 patients MRA showed present neurovascular compr ession in accordance with surgical findings (18/27 in complete accorda nce of type and side of vessel, site and direction of compression). On e woman had no neurovascular compression either on MRA or intraoperati vely. One MRA prediction of neurovascular compression was false, and t wo results were false negative. The sensitivity of MRA was therefore 8 8.5 % but the specificity only 50 %, if surgical findings are the refe rence, In one patient with right trigeminal neuralgia LL IRA revealed bilateral neurovascular compression of the Vth nerves, Therefore, the overall specificity of MRA might be below 50%. In one patient with mul tiple sclerosis, the decision to operate was markedly influenced by th e clear finding of neurovascular compression on MRA. The patient has b een free from trigeminal pain for 149 weeks after microvascular decomp ression. In 6 patients. 3D re. constructions of the MRA data were perf ormed. The images helped in 3D visualisation of the operation, but did not yield new information about the nature of the vessels revealed, o r the site, direction or side of the neurovascular compression.