In order to accurately implant the brain electrodes of carp robot for positioning and navigation, the three-dimensional model of brain structure and brain electrodes is to be proposed in the study. In this study, the tungsten electrodes were implanted into the cerebellum of a carp with the aid of brain stereotaxic instrument. The brain motor areas were found and their three-dimensional coordinate values were obtained by the aquatic electricity stimulation experiments and the underwater control experiments. The carp brain and the brain electrodes were imaged by 3.0 T magnetic resonance imaging instrument, and the three-dimensional reconstruction of carp brain and brain electrodes was carried out by the 3D-DOCTOR software and the Mimics software. The results showed that the brain motor areas and their coordinate values were accurate. The relative spatial position relationships between brain electrodes and brain tissue, brain tissue and skull surface could be observed by the three-dimensional reconstruction map of brain tissue and brain electrodes which reconstructed the three-dimensional structure of brain. The anatomical position of the three-dimensional reconstructed brain tissue in magnetic resonance image and the relationship between brain tissue and skull surface could be observed through the three-dimensional reconstruction comprehensive display map of brain tissue. The three-dimensional reconstruction model in this study can provide a navigation tool for brain electrodes implantation.
Objective To analyze the diffusion tensor imaging (DTI) characteristics and long-term prognosis of low-grade gliomas located in motor functional areas, and to evaluate the clinical significance of DTI findings and their corresponding surgical strategies. Methods A total of 71 patients with low-grade gliomas in motor functional areas who underwent surgical treatment at Beijing Tiantan Hospital, Capital Medical University between January 2014 and January 2019 were retrospectively collected. All the patients received preoperative DTI, and the minimum distance between the corticospinal tract (CST) and the lesion was less than 10 mm. Morphological changes in the CST caused by tumor invasion were evaluated. The extent of resection (EOR), postoperative paralysis rates, and long-term follow-up hemiplegia rates were reviewed. Logistic regression was used to analyze the relationship between these outcomes and DTI groupings. Patients were followed up for progression-free survival and overall survival, and Cox regression was used to analyze factors affecting prognosis. Results Based on DTI findings, patients were divided into two groups: CST Intact Group (n=49, 69.0%) and the CST Disrupt Group (n=22, 31.0%). The mean tumor volume in the CST Intact Group was significantly smaller than that in the CST Disrupt Group [(35.2±5.0) vs. (56.1±11.2) cm3, P=0.006]. Gross total or subtotal resection was achieved in 47 patients (66.2%), while 24 patients (33.8%) underwent partial resection. Univariate logistic regression showed that the EOR was associated with tumor volume [odds ratio=1.019, 95% confidence interval (CI) (1.005, 1.033), P=0.002] but not with the preoperative neurological function (P=0.702), age (P=0.216), or the integrity of CST (P=0.215). Postoperatively, 23 patients experienced hemiplegia, and 7 patients still had mild hemiplegia after six months. The CST Disrupt Group was more likely to develop postoperative hemiplegia compared to the CST Intact Group (63.6% vs. 18.4%, P<0.001). Among the 71 patients, 17 experienced tumor recurrence within 8 to 84 months. Multivariate Cox regression analysis indicated that partial resection [hazard ratio (HR)=2.115, 95%CI (1.253, 3.570), P=0.008], CST disruption [HR=2.709, 95%CI (0.999, 7.349), P=0.050], and absence of 1p19q codeletion [HR=0.258, 95%CI (0.072, 0.926), P=0.038] independently increased the risk of recurrence. Conclusions Patients with low-grade gliomas involving CST disruption have a higher risk of postoperative hemiplegia and tumor recurrence. Preoperative DTI can accurately identify the degree of motor fiber bundle involvement. Precise surgical resection is conducive to improving the total resection rate, reducing postoperative hemiplegia, and extending progression-free survival.