The Feasibility and Accuracy of Holographic Navigation with Laser Crosshair Simulator Registration on a Mixed-Reality Display.

Addressing conventional neurosurgical navigation systems' high costs and complexity, this study explores the feasibility and accuracy of a simplified, cost-effective mixed reality navigation (MRN) system based on a laser crosshair simulator (LCS). A new automatic registration method was developed, featuring coplanar laser emitters and a recognizable target pattern. The workflow was integrated into Microsoft's HoloLens-2 for practical application. The study assessed the system's precision by utilizing life-sized 3D-printed head phantoms based on computed tomography (CT) or magnetic resonance imaging (MRI) data from 19 patients (female/male: 7/12, average age: 54.4 ± 18.5 years) with intracranial lesions. Six to seven CT/MRI-visible scalp markers were used as reference points per case. The LCS-MRN's accuracy was evaluated through landmark-based and lesion-based analyses, using metrics such as target registration error (TRE) and Dice similarity coefficient (DSC). The system demonstrated immersive capabilities for observing intracranial structures across all cases. Analysis of 124 landmarks showed a TRE of 3.0 ± 0.5 mm, consistent across various surgical positions. The DSC of 0.83 ± 0.12 correlated significantly with lesion volume (Spearman rho = 0.813, p < 0.001). Therefore, the LCS-MRN system is a viable tool for neurosurgical planning, highlighting its low user dependency, cost-efficiency, and accuracy, with prospects for future clinical application enhancements.

Reorganization of the structural connectome during vision recovery in pituitary adenoma patients post-transsphenoidal surgery.

Pituitary adenomas (PAs) can exert pressure on the optic apparatus, leading to visual impairment. A subset of patients may observe a swift improvement in their vision following surgery. Nevertheless, the alterations in the structural connectome during the early postoperative period remain largely unexplored. The research employed probabilistic tractography, graph theoretical analysis, and statistical methods on preoperative and postoperative structural magnetic resonance imaging and diffusion tensor images from 13 PA patients. Postoperative analysis revealed an increase in global and local efficiency, signifying improved network capacity for parallel information transfer and fault tolerance, respectively. Enhanced clustering coefficient and reduced shortest path length were also observed, suggesting a more regular network organization and shortened communication steps within the brain network. Furthermore, alterations in node graphical properties were detected, implying a restructuring of the network's control points, possibly contributing to more efficient visual processing. These findings propose that rapid vision recovery post-surgery may be associated with significant reorganization of the brain's structural connectome, enhancing the efficiency and adaptability of the network, thereby facilitating improved visual processing.

Hyperhomocysteinemia increases the risk of vertebrobasilar dissecting aneurysm among the male Han Chinese population: a retrospective case-control study.

OBJECT: Vertebrobasilar dissecting aneurysms (VBDAs) are known to have a poor natural history with high rates of re-bleeding and mortality. There is a strong relation between hyperhomocysteinemia (HHcy) and cerebrovascular disease; we perform a retrospective study within the male of Chinese Han population to explore the association between HHcy and VBDAs. METHODS: Eighty-eight male patients with VBDA and Eighty-one male control subjects were evaluated for their serum total homocysteine levels. With multiple logistic regression analysis, the association between HHcy and the risk of VBDAs was estimated. Interaction and stratified analyses were conducted according to age, BMI, smoking status, drinking status, and chronic disease histories. The two-piecewise linear regression model examined the threshold effect. RESULTS: The multivariate logistic regression analyses revealed a significant association between HHcy and VBDAs (odds ratio (OR) = 2.62; 95% confidence interval (CI), 1.02-6.71) after adjusting for classical vascular risk factors. The relationship was stable in all subgroup analysis. The interactive role was not found in the association between HHcy and VBDAs for the potential risk factor. CONCLUSIONS: In summary, our study provides evidence that HHcy can increases the risk of VBDAs in the male Han Chinese population. Further researches with appropriate study designs including sex differences and aneurysm types are needed to verify this association.

MR Imaging, MGMT Promoter Methylation Features and Prognostic Analysis of Subventricular Zone Contacting IDH Wild-type Glioblastoma.

BACKGROUND: As the largest concentration of neural stem cells in adult brain, the subventricular zone (SVZ) is considered to be a potential source of glioblastoma (GBM) occurrence in recent years. METHODS: In this study, 116 patients with glioblastoma treated at PLA General Hospital were retrospectively reviewed. The features of SVZ contacting glioblastoma were analyzed in terms of MR imaging and MGMT promoter methylation. We also evaluated the prognostic value of SVZ contacting in GBM patients. RESULTS: GBM with SVZ involvement on MRI is more likely to grow across the midline (36.8% vs. 6.9%, P=0.002), more often multifocal lesion (35.6% vs. 6.9%, P=0.003) and have a lower proportion of MGMT promoter methylation (36.8% vs. 69.0%, P=0.003). The median overall survival and progression- free survival of patients in the SVZ contacting group were 12 months and 7 months, while 25 months and 17 months in the non-contacting group (P<0.001, respectively). There was no significant difference in overall survival (P=0.229) and progression-free survival (P=0.808) between patients with different SVZ contacting regions. Multivariate survival analysis indicated that patients with MRI SVZ involvement showed worse overall survival (HR=2.060, 95%CI 1.195-3.550，P=0.009) and progression- free survival (HR=3.021, 95%CI 1.788-5.104，P＜0.001). CONCLUSION: This study suggested that MRI SVZ involvement at diagnosis is an independent risk factor for overall survival and progression-free survival in IDH wild-type glioblastoma patients. Based on MR imaging, we also found that SVZ contacting glioblastomas had a larger proportion of crossing midline tumors and multifocal lesions. In addition, patients with SVZ contact in our research presented a lower proportion of MGMT promoter methylation.

The imaging features and prognosis of gliomas involving the subventricular zone: An MRI study.

RATIONALE AND OBJECTIVES: As the largest concentrated region of neural stem cells in the adult brain, the subventricular zone (SVZ) is considered to have a close relationship with the origin of gliomas. An in-depth study of the characteristic manifestations associated with SVZ involvement in glioma may provide new ideas for individualized diagnosis and treatment of this fatal disease. MATERIALS AND METHODS: All 279 patients with glioma who underwent surgical treatment in our department from January 2016 to December 2021 were included. Clinical and imaging data were collected, and telephonic follow-up was conducted to analyze the overall survival and progression-free survival. Prognostic factors including SVZ involvement on glioblastoma patients' survival were analyzed. Next, the relationship between SVZ involvement, a set of unique imaging features and gene status were determined respectively. The chi-squared test, logistics regression, and Cox regression were used for statistical analysis. RESULTS: The patients were divided into the SVZ involvement group (n = 198, 70.97 %) and SVZ non-involvement group (n = 81, 29.03 %). The median overall survival and progression-free survival were 13 months and 7 months for the SVZ involvement group, but 25 months and 17 months for the SVZ non-involvement group, respectively. In multivariate Cox survival analysis, MRI SVZ involvement proved an independent risk factor for the survival of patients with glioblastoma. The patients with SVZ involvement sign had a lower rate of cystic lesion (32.32 % vs. 48.48 %, p = 0.029), and a larger mean maximum diameter (5.88 ± 1.28 vs. 3.28 ± 1.65 cm). Compared with high grade gliomas (HGG), T1 enhancement (25.25 % vs. 10.42 %, p = 0.041) and homogeneous signal on T2WI (14.14 % vs. 43.75 %, p = 0.025) were independently associated with SVZ involvement in WHO grade 2 gliomas(LGG). In the gene status analysis, the SVZ involvement group showed the lower rate of MGMT promoter methylation (57.58 % vs. 79.17 %, p = 0.017). CONCLUSION: SVZ involvement in MRI at diagnosis is an independent negative prognostic indicator for the survival of glioblastoma patients. Some image signs are associated with SVZ involvement in HGG and LGG respectively. The unique imaging and gene features of gliomas with SVZ involvement indicate that this kind of tumor maybe a unique subgroup of gliomas.

A novel 3D-vision-based collaborative robot as a scope holding system for port surgery: a technical feasibility study.

OBJECTIVE: A clear, stable, suitably located vision field is essential for port surgery. A scope is usually held by hand or a fixing device. The former yields fatigue and requires lengthy training, while the latter increases inconvenience because of needing to adjust the scope. Thus, the authors innovated a novel robotic system that can recognize the port and automatically place the scope in an optimized position. In this study, the authors executed a preliminary experiment to test this system's technical feasibility and accuracy in vitro. METHODS: A collaborative robotic (CoBot) system consisting of a mechatronic arm and a 3D camera was developed. With the 3D camera and programmed machine vision, CoBot can search a marker attached to the opening of the surgical port, followed by automatic alignment of the scope's axis with the port's longitudinal axis so that optimal illumination and visual observation can be achieved. Three tests were conducted. In test 1, the robot positioned a laser range finder attached to the robot's arm to align the sheath's center axis. The laser successfully passing through two holes in the port sheath's central axis defined successful positioning. Researchers recorded the finder's readings, demonstrating the actual distance between the finder and the sheath. In test 2, the robot held a high-definition exoscope and relocated it to the setting position. Test 3 was similar to test 2, but a metal holder substituted the robot. Trained neurosurgeons manually adjusted the holder. The manipulation time was recorded. Additionally, a grading system was designed to score each image captured by the exoscope at the setting position, and the scores in the two tests were compared using the rank-sum test. RESULTS: The CoBot system positioned the finder successfully in all rounds in test 1; the mean height errors ± SD were 1.14 mm ± 0.38 mm (downward) and 1.60 mm ± 0.89 mm (upward). The grading scores of images in tests 2 and 3 were significantly different. Regarding the total score and four subgroups, test 2 showed a more precise, better-positioned, and more stable vision field. The total manipulation time in test 2 was 20 minutes, and for test 3 it was 52 minutes. CONCLUSIONS: The CoBot system successfully acted as a robust scope holding system to provide a stable and optimized surgical view during simulated port surgery, providing further evidence for the substitution of human hands, and leading to a more efficient, user-friendly, and precise operation.