Artikel
Value of high-resolution MRI of the parapontine region in the diagnosis of trigeminal neuralgia
Stellenwert der hochauflösenden MRT des Kleinhirnbrückenwinkels in der Diagnostik der Trigeminus-Neuralgie
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Veröffentlicht: | 30. Mai 2008 |
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Gliederung
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Objective: The diagnosis of trigeminal neuralgia (TN) is based on clinical neurological findings and the subjective pain description of the patient. The role of MRI in the preoperative diagnosis is mainly intended for the exclusion of symptomatic neuralgia due to possible tumours or inflammation. MRI-visualization of the neurovascular contact is indifferent and in many cases also seen on the healthy side or in painfree controls. In this prospective study, additional morphological and volumetric data with high resolution MRI of the parapontine region is to be investigated and significant differences defined.
Methods: In 62 patients with unilateral TN and in 48 healthy volunteers, high-resolution MRI (1.5 T MRI-scanner) of the parapontine cistern was performed. Volumetric measurements were performed using a T2-weighted CISS-sequence (Constructive interference steady state, TE: 5.6, TR: 11.2, FoV 230, matrix 256, slice thickness: 0.9 mm, time: 5:36 min.) with coronal reconstruction. In each patient the volume of the trigeminal nerve and of the parapontine cistern as well as the course and angulations of the trigeminal nerve through the parapontine cistern was investigated intraindividually on both sides. The neuroradiologist was blinded for the diagnosis and the side of TN.
Results: Significant side differences were found for the volume of the affected nerve and also for the parapontine cistern in patients with TN (p<.01; p<.005). No significant side differences were found in the volunteer group. Measurements of the angulations of the trigeminal nerve revealed a smaller angle between the nerve and Meckel's cave on the affected side in patients (p<.005).
Conclusions: High resolution MRI of the trigeminal nerve and parapontine region offers the possibility of achieving additional morphological parameters in patients with trigeminal neuralgia. Significant side differences of the volume of the affected trigeminal nerve and parapontine cistern and the angulation of the cisternal nerve portion and Meckel's cave were found. Based on these findings, additional criteria for the identification of good candidates for microvascular decompression should be taken into consideration.