The usefulness of 3.0T MRI in the localization of primary trifacial neuralgia treated with Gamma knife surgeryJiamin Li1, Xiaogang Sun2, Yongli Tan21 2Zibo Wanjie Cancel Hospital, Shandongï¼ŒPeopleâ€™s Repulic of China Keywords: trigeminal neuralgia, Imaging, pain, gamma knife, outcome
Trigeminal neuralgia radiosurgery is commonly performed, usually guided by 1.5T MRI.
Our purpose was to assess the effectiveness and related factors of 3.0T MRI in the localization of primary trigeminal neuralgia treated with Gamma knife surgery.
Thirty patients were evaluated.
During Oct. 2008 and Feb. 2011, 30 patients were treated Gamma knife, magnetic resonance angiography (MRA) and 3D-TOF-SPER sequence and 3D-Fiesta sequence, and 3mm non-gap scanning were used for the localization. Image fusion were used to combine 1mm-thin layer’s cranial nerve scanned image and localization image to optimize dose planning. 4mm collimator were used. Two targets were set along the trifacial root near brain stem and 2 isocenters were employed ,50% isodose line surrounding the trifacial nerve entering the brain stem part, with major axis 1cm at most, central dose 80~90Gy, dose to the brain stem surface was less than 16~18Gy. For the patients taking second course of GKS, the target volume and the dose are same to the first treatment.
Follow-up time was 2-37 months, among 30 patients, pain disappeared completely was found in 18 patients(60%) without analgesic; Pain remission was found in 5 cases (17%) with analgesic occationally,and pain remission with reduced analgesic was found in 3 cases (10%), no pain relief in 4 cases (13%). the whole efficiency rate is about 87%. Relapse is found in 2 cases after 2-24 months, and second course of GKS was given, and then the pain vanishes completely.
This was a retrospective series.
Clear images of the trigeminal nerve root with high field-intensity MRI is one of the key factors to improve the effectiveness of GKS for primary trifacial neuralgia. GKS is a safe, effective approach in the treatment of primary trigeminal neuralgia. A second treatment after the recrudescence is effective, though more complications including facial numbness occur.
J. Li (), X. Sun (), Y. Tan ()