Usefulness of MRI to Identify Vascular Contact in Patients With Classical Trigeminal Neuralgia: A Pilot Study

Objectives: To evaluate MRI as a diagnostic tool in diagnosis of Trigeminal Neuralgia and to emphasize its need in routine diagnostic protocol.
Methods: This is a prospective diagnostic accuracy study in which 20 consecutive cases of clinically confirmed classical trigeminal neuralgia patients underwent Magnetic Resonance Imaging of the brain in a 1.5 Tesla Machine. The sequences include Axial T2W TSE, GRE T2 FLAIR, Sagittal T1W SE and Coronal T2W TSE & DW I.
Results: Among the 20 cases male and female were equal in numbers (10 each). 55% (n=11) cases were in the age group of 51 years to 60 years which is the highest predilection. A vascular loop around the nerve is positive in 70% (n=14) cases among which 13 cases showed positive compression and 1 case did not show evidence of compression. Current literature states Trigeminal neuralgia is common in the right side but our study shows a predilection to the left side 85% (n=12). The commonest site of compression is the root entry zone which is about 45% (n=9) as supported by the literature and other sites of nerve involvement made the remaining 35%. There is a significant correlation between the presence of vascular loop around the nerve and the compression caused by the vessel on the nerve with a P-value of 0.05, likelihood ratio of .05, Fisher exact test value of 0.78.
Conclusions: Among the 20 cases of classic trigeminal neuralgia 14 cases demonstrated vascular loop around the trigeminal nerve at various levels and 93% of it showed evidence of nerve compression in MRI. Hence MRI is mandatory in diagnosis of Trigeminal neuralgia. As vascular compression is the commonest cause the remaining 6 cases might also have minor changes in the nerve or artery which could be elicited by an advanced neuroimaging on which further research is required.