A Blinded, Case-Control Trial Assessing the Value of Steady State Free Precession Magnetic Resonance Imaging in the Diagnosis of Trigeminal Neuralgia

Abstract

High-resolution magnetic resonance imaging (MRI) may be a useful and readily available adjunct in identifying trigeminal neuralgia secondary to vascular contact (TNVC). This study evaluated the reliability and predictive ability of 1.5-tesla steady state free precession (SSFP) MRI sequences for the diagnosis of symptomatic vascular contact and response to operative intervention in patients with TNVC. We performed a blinded, case-matched control trial evaluating SSFP MRI sequences in consecutive patients with unilateral TNVC with operatively proven vascular contact of the trigeminal nerve compared with healthy control subjects matched on age, sex, and laterality of the pathologic neurovascular complex. Interrater reliability was compared between 2 blinded, expert reviewers. Predictive ability of MRI was assessed in regard to accuracy, discrimination, and clinical utility. Inclusion criteria were met by 44 patients (22consecutive patients with TNVC and 22 matched control subjects). Interrater reliability ranged from fair to excellent for vessel contact (κ= 0.40), location (κ= 0.81), type (κ= 0.72), and multiplicity (κ= 0.31). Vascular contact on MRI sequences did not differ significantly between cases and controls (75% vs. 82%, P= 0.30). MRI demonstrates accurate (Brier 0.15) and good discriminatory ability for clinical response after microvascular decompression (area under the receiver operating characteristic curve 0.81, 95% confidence interval= 0.6-1.0). Decision-curve analysis demonstrated that MRI could result in a net reduction of 5 cases likely to be unsuccessful per 100 patients treated. These results suggest the utility of SSFP MRI lies not in the diagnosis of TNVC, but rather in stratifying the likelihood of response to microvascular decompression in patients with characteristic symptoms.