Article
Additional morphological criteria concerning the neurovascular compression theory in trigeminal neuralgia observed with high resolution MRI
Zusätzliche morphologische Kriterien bezüglich der neurovaskulären Kompressionstheorie bei Trigeminus-Neuralgie untersucht mit hochauflösender Kernspintomographie
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Published: | May 4, 2005 |
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Outline
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Objective
The pathophysiological cause of idiopathic trigeminal neuralgia (TN) is still unknown and the discussion about the neurovascular compression theory is going on. Preoperative magnetic resonance imaging is performed to exclude a symptomatic cause like a tumour or inflammation. Efforts are made to visualise a neurovascular compression of the trigeminal nerve root near the brainstem. In this prospective study high resolution MRI was performed and additional morphological criteria like nerve atrophy, volume of the parapontine cistern etc. were measured.
Methods
50 patients with TN and 50 healthy controls were examined using a 1.5 Tesla Scanner (Symphony, Siemens, Germany) and a high resolution T2-TrueFisp sequence with a slice thickness of 0.3 mm to create a 3D-volume. Also a T1-Flash-3D-vibe sequence (+/- gadolinium iv) with 0.9 mm slice thickness was acquired.
Results
A neurovascular conflict was found in 45/50 patients with TN (90%) and 38/50 healthy controls (76%). In 37 patients with TN volumetry was performed and identified a significant smaller volume of the involved nerve and ipsilateral pontomesencephalic cistern (p<0.05). In all patients the angle of the trigeminal nerve from its entry point in the pons to the gasserian ganglion was significantly steeper compared with the non-affected side (p<0.05).
Conclusions
In patients with TN high resolution MRI can demonstrate specific morphological differences of the affected and non-affected trigeminal nerves. A smaller volume of the nerve, pontomesencephalic cistern and a steeper angle in the cistern have to be taken into account as additional criteria supporting the neurovascular compression theory.