The value of MRI TOF and CISS sequence to the operation of trigeminal neuralgia decompression

Abstract

Objective To demonstrate the spatial relationship between intracisternal segment of trigeminal nerve and adjacent vessels in patients with primary trigeminal neuralgia and to assess the effectiveness of magnetic resonance imaging (MRI) for diagnosis of the neurovascular contact.Methods 89patients underwent trigeminal nerve decompression operation from January 2011 to November 2012.Preoperative 1.5T MRI with axial time-of-flight (TOF) sequence and constructive interference in steady state (CISS) sequence were performed.And then the bilateral spatial relationship between intracisternal segment of trigeminal nerve and adjacent vessels were studied.The surgical video recordings were golden standards for comparative analysis of the different results between TOF,CISS and CISS + TOF.Results Confirmed by the operative video recordings,the contact vessels were superior cerebellar artery in 32 cases (35.6％),anterior inferior cerebellar artery in 3 cases (3.3％),vein in 8 cases (8.9％),composite vessels in 44 cases (48.9％),no obvious vascular in 3 cases (3.3％).The accuracies of TOF,CISS,and CISS + TOF to for the diagnosis of the neuralgia side were 56.7％,53.4％ and 56.2％,respectively.The sensitivities of TOF,CISS,and CISS + TOF for the diagnosis of the existence of contact vessels on the neuralgia sides were 74.7％,85.1％ and 93.1％,respectively.The difference between TOF and CISS + TOF was statistically significant.However,the consistency of all three groups for the diagnosis of the type of contact vessels was low,from 0％ to 55.6％.Conclusions Preoperative MRI could not accurately determine the trigeminal neuralgia pain in which side.The combined CISS and TOF sequence examination could accurately determine whether the contact vessels existed on the neuralgia sides.But in this study MRI examination could not accurately determine the types of contact vessels. Key words: Trigeminal neuralgia ; Magnetic resonance imaging; Microvascular decompression