Three-dimensional time-of-flight MR angiography in trigeminal neuralgia ona 0.5-T system

The goal of this study was to analyze the diagnostic value of three-dimensi onal time-of-flight magnetic resonance angiography (3D TOF MRA), performed on, a 0.5-T system in the detection of neurovascular compression in patient s with trigeminal neuralgia (TN). One hundred seventy-two TN patients were examined using plain and contrast-enhanced 3D TOF MRA on a 0.5-T system. Ma ximum intensity projection (MIP) reconstruction was performed in three stan dard planes. Both the original and the reconstructed images were studied to search for vascular compression shown by close neurovascular contact and/o r dislocation of the trigeminal nerve. Forty-two TN patients underwent surg ical exploration of the posterior fossa. Results of MRA were compared with clinical data in all cases and to results of surgery in the surgically trea ted cases. Neurovascular contact at the root entry zone of the trigeminal n erve was detected on the symptomatic side in 94 patients, and on the asympt omatic side in 12 patients. Sensitivity, specificity, accuracy, as well as positive and negative predictive value of 3D TOF MRA in the detection of ne urovascular compression in the patient group undergoing surgery, were 97.6, 92.5, 95.0, 93.0, and 97.4 %, respectively. Three-dimensional TOF MRA perf ormed on a 0.5-T system appears to be not less effective than similar exami nations by higher field strength devices in the detection of neurovascular contact. This sequence accurately demonstrates the presence of neurovascula r compression, and in this way valuable information may be achieved for the planning of surgical therapy of patients with trigeminal neuralgia.