gms | German Medical Science

Objective: MRI of neurovascular relationship still shows a limited specificity in trigeminal neuralgia. In 40% of healthy persons MRI reveals asymptomatic neurovascular contacts of the N.V. Are there specific detectable signs in imaging and visualization to be correlated trigeminal neuralgia and its clinical appearance?

Method: 180 patients with TN underwent MRI-CISS and TOF. The imaging data were segmented and 3D visualization was performed. We analyzed the data referring four parameters: (P1) correlation of compression site (caudal/cranial/laterocaudal/mediocranial side of the nerve) to clinically affected area (V1,V2,V3). (P2) nerve deformation morphology. (P3) causative vascular loop. (P4) the existence of a so called “CSF sign” caused by a mechanical separation of trigeminal fascicles by a vessel. These results of visualization were correlated to the intraoperative findings.

Results: (P1) correlation of compression site to clinically affected area: cranial/caudal/laterocaudal/medicranial: V1 (n=10): 6/0/0/4. V2 (n=26): 17/0/1/8. V3 (n=29): 23/1/3/2. V1&V2 (n=25): 17/1/0/7. V2&V3 (n=36): 30/3/1/2. V1&V2&V3 (n=6): 4/1/0/1. (P2): 63 patients (35%) showed nerval deformity by distorsion of the trigeminal fascicles from compressing vessel. 37 of 39 patients (95%) with right-sided deformity showed right-sided neuralgia. 21 of 22 patients with left sided neuralgia showed a left sided nerve deformation. 2 patients with bilateral nerve deformity showed bilateral neuralgia. (P3): Rostral SCA loop compression was seen in n=24 patients (17%). Caudal SCA loop compression was seen in n=10 (7%). Double SCA loop compression was seen in n=33 (23%). A sandwich compression by SCA and another arterial or venous vessel was seen in n=18 (12%). (P4): CSF sign was seen in 24 patients. All 24 patients (100%) with a CSF sign had V1-affection. The examined parameters could be implemented in 110 of 144 patients (76%) with arterial compression.

Conclusions: MRI provided significant findings in correlation with clinical symptoms. We were able to evaluate 76% of the examined patients with the suggested parameters. The CSF sign is pathognomonic for V1-affection. We found a vascular loop from cranial on the nerve as the most frequent type of compression in all areas of pain, followed by mediocranial loops. This evaluation is reproducible and contributes to the role of MR imaging and a classification of findings in the preoperative evaluation of NVC.