Up to now, multiplanar reconstruction (MPR) has been widely used to detect the neurovascular compressions (NVC) on the patients with idiopathic trigeminal neuralgia (ITN). However, due to lack of stereoscopic vision, this traditional method sometimes cannot meet the requirement on identifying the existence and details of NVC, especially when the aberrant vessels turn out to be delicate veins. The three-dimensional analytic techniques, such as curved planar reconstruction (CPR) and magnetic resonance virtual endoscopy (MRVE), may be helpful to improve the sensitivity and specificity on the demonstration of NVC with stereo and dynamic views, so as to assist to design the surgical plan. Furthermore, the frequent finding of NVC on MRI studies of asymptomatic patients incited the creation of several strict criteria for the imaging diagnosis of NVC: the vessel must cross perpendicular to the long axis of the nerve, the nerve must be deviated or indented at the root entry zoon (REZ) by the vessel. Alternatively, morphological measurement of the nerve may correlate with the severity of facial pain due to atrophy of the nerve in most cases of ITN, and is likely secondary to the micro-structural abnormalities, such as axonal loss, demyelination, collagen deposition, etc. In this study, cross-sectional area (CSA) and volume (V) of the cisternal trigeminal nerve will be assessed to determine whether it can be a useful biomarker for predicting the degree of ITN.
Study Type
OBSERVATIONAL
Enrollment
55
3.0-T MRI scanner (Signa HDxt; GE Medical Systems, WI, USA)
Xi'an, Shaanxi, China
Change from Baseline V (mm3) at 12 months
Baseline V (mm3) refers to the volume of the cisternal trigeminal nerve prior to the surgical treatment. Meanwhile, the study endpoint is 12 months after the operation, which need another measurement of V. Measurements of V will be performed using Medical Image Processing, Analysis, and Visualization software (MIPAV, http://mipav.cit.nih.gov/). The measurements start from the point where the nerves enter the pons to an imaginary demarcation made at the entrance of the nerves into Meckel's cave. The trigeminal nerves are manually delineated in each traverse section. The V will be automatically calculated with the MIPAV software.
Time frame: 0, 12 months
Change from Baseline CSA (mm2) at 12 months
Baseline CSA (mm2) refers to the cross sectional area of the cisternal trigeminal nerve prior to the surgical treatment. Meanwhile, the study endpoint is 12 months after the operation, which need another measurement of CSA. The CSA is calculated at 5 mm from the entry of the trigeminal nerve into the pons in an image plane perfectly perpendicular to the course of each nerve, which also need using a mouse-driven cursor in MIPAV software.
Time frame: 0, 12 months
Sensitivity and Specificity of Detection of Neurovascular Compression by MPR Compared with Surgical Findings
Severity of neurovascular compression, which will be judged by MPR, is defined as follows: 1 = no compression; 2 = contact by a vessel; 3 = indentation by a vessel; and 4 = nerve displacement or distortion by a vessel, and the results of MPR need to be compared with the intraoperative findings to obtain the sensitivity and specificity, respectively.
Time frame: 0 (baseline)
Sensitivity and Specificity of Detection of Neurovascular Compression by CPR Compared with Surgical Findings
Severity of neurovascular compression, which will be judged by CPR, is the same criterion as that in the Outcome 3, and the results of CPR need to be compared with the intraoperative findings to obtain the sensitivity and specificity, respectively.
Time frame: 0 (baseline)
Sensitivity and Specificity of Detection of Neurovascular Compression by MRVE Compared with Surgical Findings
Severity of neurovascular compression, which will be judged by MRVE, is the same criterion as that in the Outcome 3, and the results of MRVE need to be compared with the intraoperative findings to obtain the sensitivity and specificity, respectively.
Time frame: 0 (baseline)
Change from Baseline Visual Analog Score (VAS) for Pain at 12 months
Baseline VAS will be evaluated by Visual Analog Scale for Pain prior to the operations. Graphic formats for the VAS can be obtained online: http:// www.amda.com/tools/library/whitepapers/hospiceinltc/appendix-a.pdf. Meanwhile, the study endpoint is 12 months after the operation, which need another measurement of VAS.
Time frame: 0, 12 months
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