The choice of microvascular decompression (MVD), among the several other surgical options, for treating refractory classical trigeminal neuralgia (TN) relies mostly on preoperative imaging, but the degree of reliability of MRI remains a matter of debate. The authors approached the question of predictability of neurovascular conflict (NVC) in a series of 100 protocolized MRI studies from patients with TN who underwent MVD, by reexamination of MR images, blinded to the clinical data and surgical findings, including the side of the neuralgia.
Patients included in the study were those who underwent MVD after surgical indication had been determined based on a protocolized imagery workup (3D high-resolution T2-weighted cisternography centered on the trigeminal nerve, 3D time-of-flight angiography, and 3D gadolinium-enhanced T1-weighted imaging) performed at our institution. All MR images were blindly reexamined, and neurovascular relationships were described on both sides, noting the existence of compression, vessels involved, situation along the root, and degree of compression. The results of MRI evaluation were then compared with actual surgical findings. The extent of agreement and quality of the prediction were expressed with Cohen’s kappa coefficient (κ) and receiver operating characteristic (ROC) statistics.
A conflict had actually been found during surgery in 94 of 100 patients. The sensitivity of MRI to detect a conflict was 97% and the specificity was 50%. Vessel type was identified with high reliability (κ = 0.80), while the grade of the conflict and its situation along the root showed poor to average reliability (κ = 0.38 and κ = 0.40, respectively). The area under the ROC curve for predicting the presence of a conflict according to the grades of conflict seen on MRI was 0.93, which is considered very good. The positive predictive value was differentiated according to the grade of conflict, with a very high value for high grades of vascular conflict.
This study shows an overall good reliability of MRI to predict the existence of an NVC. The prediction value is excellent for high grades of compression. Some apparent low-grade compressions on MRI may be revealed as false positives in surgical exploration. This raises the question of what other imaging methods might be used to determine not only the existence of a conflict but also its degree of compression. The degree of compression is of paramount importance to predict the probability of long-term pain relief, and therefore in the decision to propose MVD as the first choice of surgical treatment.
ABBREVIATIONSAICA = anterior inferior cerebellar artery; BA = basilar artery; MVD = microvascular decompression; NVC = neurovascular conflict; NVR = neurovascular relationship; ROC = receiver operating characteristic; SCA = superior cerebellar artery; SPVS = superior petrosal venous system; TN = trigeminal neuralgia; TOF = time of flight; TREZ = trigeminal root entry zone; VA = vertebral artery.
AndersonVCBerryhillPCSandquistMACiaverellaDPNesbitGMBurchielKJ: High-resolution three-dimensional magnetic resonance angiography and three-dimensional spoiled gradient-recalled imaging in the evaluation of neurovascular compression in patients with trigeminal neuralgia: a double-blind pilot study. Neurosurgery58:666–6732006
AntoniniGDi PasqualeACruccuGTruiniAMorinoSSaltelliG: Magnetic resonance imaging contribution for diagnosing symptomatic neurovascular contact in classical trigeminal neuralgia: a blinded case-control study and meta-analysis. Pain155:1464–14712014
Boecher-SchwarzHGBruehlKKesselGGuenthnerMPerneczkyAStoeterP: Sensitivity and specificity of MRA in the diagnosis of neurovascular compression in patients with trigeminal neuralgia. A correlation of MRA and surgical findings. Neuroradiology40:88–951998
ChenMJZhangWJGuoZLYangCZhangWHDongMJ: Preoperative evaluation of the neurovascular compression using magnetic resonance tomographic angiography: our radiologic indications for microvascular decompression to treat trigeminal neuralgia. J Craniofac Surg25:e384–e3882014
Chun-ChengQQing-ShiZJi-QingZZhi-GangW: A single-blinded pilot study assessing neurovascular contact by using high-resolution MR imaging in patients with trigeminal neuralgia. Eur J Radiol69:459–4632009
DumotCBrinzeuABerthillerJSindouM: Trigeminal neuralgia due to venous neurovascular conflicts: outcome after microvascular decompression in a series of 55 consecutive patients. Acta Neurochir (Wien)159:237–2492017
LangENaraghiRTanrikuluLHastreiterPFahlbuschRNeundörferB: Neurovascular relationship at the trigeminal root entry zone in persistent idiopathic facial pain: findings from MRI 3D visualisation. J Neurol Neurosurg Psychiatry76:1506–15092005
LealPRLBarbierCHermierMSouzaMACristino-FilhoGSindouM: Atrophic changes in the trigeminal nerves of patients with trigeminal neuralgia due to neurovascular compression and their association with the severity of compression and clinical outcomes. J Neurosurg120:1484–14952014
LealPRLHermierMFromentJCSouzaMACristino-FilhoGSindouM: Preoperative demonstration of the neurovascular compression characteristics with special emphasis on the degree of compression, using high-resolution magnetic resonance imaging: a prospective study, with comparison to surgical findings, in 100 consecutive patients who underwent microvascular decompression for trigeminal neuralgia. Acta Neurochir (Wien)152:817–8252010
LealPRLRochJAHermierMSouzaMANCristino-FilhoGSindouM: Structural abnormalities of the trigeminal root revealed by diffusion tensor imaging in patients with trigeminal neuralgia caused by neurovascular compression: a prospective, double-blind, controlled study. Pain152:2357–23642011
MasudaYYamamotoTAkutsuHShiigaiMMasumotoTIshikawaE: Usefulness of subtraction of 3D T2WI-DRIVE from contrast-enhanced 3D T1WI: preoperative evaluations of the neurovascular anatomy of patients with neurovascular compression syndrome. AJNR Am J Neuroradiol36:317–3222015
MeaneyJFEldridgePRDunnLTNixonTEWhitehouseGHMilesJB: Demonstration of neurovascular compression in trigeminal neuralgia with magnetic resonance imaging. Comparison with surgical findings in 52 consecutive operative cases. J Neurosurg83:799–8051995
MistryAMNiesnerKJLakeWBForbesJAShannonCNKaslRA: Neurovascular compression at the root entry zone correlates with trigeminal neuralgia and early microvascular decompression outcome. World Neurosurg95:208–2132016
PatelNKAquilinaKClarkeYRenowdenSACoakhamHB: How accurate is magnetic resonance angiography in predicting neurovascular compression in patients with trigeminal neuralgia? A prospective, single-blinded comparative study. Br J Neurosurg17:60–642003
PekerSDinçerANecmettin PamirM: Vascular compression of the trigeminal nerve is a frequent finding in asymptomatic individuals: 3-T MR imaging of 200 trigeminal nerves using 3D CISS sequences. Acta Neurochir (Wien)151:1081–10882009
SatohTOmiMNabeshimaMOnodaKDateI: Severity analysis of neurovascular contact in patients with trigeminal neuralgia: assessment with the inner view of the 3D MR cisternogram and angiogram fusion imaging. AJNR Am J Neuroradiol30:603–6072009
SindouMHoweidyTAcevedoG: Anatomical observations during microvascular decompression for idiopathic trigeminal neuralgia (with correlations between topography of pain and site of the neurovascular conflict). Prospective study in a series of 579 patients. Acta Neurochir (Wien)144:1–132002
SindouMLestonJDecullierEChapuisF: Microvascular decompression for primary trigeminal neuralgia: long-term effectiveness and prognostic factors in a series of 362 consecutive patients with clear-cut neurovascular conflicts who underwent pure decompression. J Neurosurg107:1144–11532007