The value of multimodal imaging fusion in preoperative visualization assessment of neurovascular relationship in hemifacial spasm: a single-center retrospective study
Authors: Wang Yinzhan , Li Yang , Shi Hailiang , Du Yihui , Guo Wenchang , Shi Haowei , Qian Tao 
Published: April 2024

Background
The neurovascular conflict (NVC) at the brainstem exit zone of the facial nerve is considered the primary etiology of primary hemifacial spasm (HFS). Therefore, microvascular decompression (MVD) has become the preferred treatment for HFS. Successful neurovascular decompression can achieve significant therapeutic effects, and accurately identifying the site of compression is crucial for the success of this surgery. Detailed diagnostic neuroimaging plays an important role in accurately identifying the site of compression.The purpose of this study is to explore the feasibility and predictive value of preoperative visualization assessment of the neurovascular relationship in HFS using 3D-slicer software based on multimodal imaging fusion.
Methods
This study retrospectively analyzed 80 patients with HFS who underwent MVD surgery. All patients underwent preoperative cranial MRI scans, including 3D-FIESTA and 3D-TOF MRA sequences. Three-dimensional models were reconstructed based on multimodal MRI images using 3D-slicer software. Then, independent observers unaware of the surgical outcomes evaluated the neurovascular relationships using both the three-dimensional models and multimodal MRI images. The assessment results were compared with intraoperative findings, and statistical analysis was performed using SPSS 22.0 software.
Results
The agreement between preoperative assessment using 3D-TOF MRA sequence combined with 3D-FIESTA sequence and intraoperative findings was represented by a Kappa value of 0.343, while the Kappa value for agreement between three-dimensional reconstruction and intraoperative findings was 0.637. There was a statistically significant difference between the two methods ( X2 = 18.852, P = 0.001 ). The sensitivity and specificity of the 3D-TOF MRA sequence combined with 3D-FIESTA sequence for evaluating neurovascular relationships were 92.4% and 100%, respectively, while for three-dimensional reconstruction, both were 100%. The Kappa value for agreement between preoperative 3D-TOF MRA sequence combined with 3D-FIESTA sequence prediction of offending vessels and intraoperative findings was 0.625, while the Kappa value for agreement between three-dimensional reconstruction and intraoperative findings was 0.938, showing a statistically significant difference ( X2 = 317.798, P = 0.000 ). The Kappa value for agreement between preoperative 3D-TOF MRA sequence combined with 3D-FIESTA sequence assessment of the anatomical location of facial nerve involvement in neurovascular compression and intraoperative findings was 0.608, while the Kappa value for agreement between three-dimensional reconstruction and intraoperative findings was 0.918, also showing a statistically significant difference ( X2 = 504.647, P = 0.000 ).
Conclusions
The preoperative visualization assessment of neurovascular relationships in HFS using 3D-slicer software based on multimodal imaging fusion has been demonstrated to be reliable. It is more accurate than combining 3D-TOF MRA sequence with 3D-FIESTA sequence and shows higher consistency with intraoperative findings. This method is more helpful in preoperative surgical planning and guiding surgery.