OBJECTIVE

Automatic segmentation of vestibular schwannomas (VSs) from MRI could significantly improve clinical workflow and assist in patient management. Accurate tumor segmentation and volumetric measurements provide the best indicators to detect subtle VS growth, but current techniques are labor intensive and dedicated software is not readily available within the clinical setting. The authors aim to develop a novel artificial intelligence (AI) framework to be embedded in the clinical routine for automatic delineation and volumetry of VS.

METHODS

Imaging data (contrast-enhanced T1-weighted [ceT1] and high-resolution T2-weighted [hrT2] MR images) from all patients meeting the study’s inclusion/exclusion criteria who had a single sporadic VS treated with Gamma Knife stereotactic radiosurgery were used to create a model. The authors developed a novel AI framework based on a 2.5D convolutional neural network (CNN) to exploit the different in-plane and through-plane resolutions encountered in standard clinical imaging protocols. They used a computational attention module to enable the CNN to focus on the small VS target and propose a supervision on the attention map for more accurate segmentation. The manually segmented target tumor volume (also tested for interobserver variability) was used as the ground truth for training and evaluation of the CNN. We quantitatively measured the Dice score, average symmetric surface distance (ASSD), and relative volume error (RVE) of the automatic segmentation results in comparison to manual segmentations to assess the model’s accuracy.

RESULTS

Imaging data from all eligible patients (n = 243) were randomly split into 3 nonoverlapping groups for training (n = 177), hyperparameter tuning (n = 20), and testing (n = 46). Dice, ASSD, and RVE scores were measured on the testing set for the respective input data types as follows: ceT1 93.43%, 0.203 mm, 6.96%; hrT2 88.25%, 0.416 mm, 9.77%; combined ceT1/hrT2 93.68%, 0.199 mm, 7.03%. Given a margin of 5% for the Dice score, the automated method was shown to achieve statistically equivalent performance in comparison to an annotator using ceT1 images alone (p = 4e−13) and combined ceT1/hrT2 images (p = 7e−18) as inputs.

CONCLUSIONS

The authors developed a robust AI framework for automatically delineating and calculating VS tumor volume and have achieved excellent results, equivalent to those achieved by an independent human annotator. This promising AI technology has the potential to improve the management of patients with VS and potentially other brain tumors.

OBJECTIVE

Benign peripheral nerve sheath tumors (PNSTs) include mainly schwannomas—the most common tumors arising from peripheral nerves—and neurofibromas. Due to their origin, distinguishing between functional intact nerve and the fibers from whence the PNST arose may not always be easy to perform. The introduction of intraoperative tools to better visualize these tumors could be helpful in achieving a gross-total resection. In this study, the authors present a series of patients harboring PNST in which the surgery was performed under fluorescein guidance.

METHODS

Between September 2018 and February 2019, 20 consecutive patients with a total of 25 suspected PNSTs underwent fluorescein-guided surgery performed under microscopic view with a dedicated filter integrated into the surgical microscope (YELLOW 560) and with intraoperative monitoring. All patients presented with a different degree of contrast enhancement at preoperative MRI. Fluorescein was intravenously injected after intubation at a dose of 1 mg/kg. Preoperative clinical and radiological data, intraoperative fluorescein characteristics, and postoperative neurological and radiological outcomes were collected and analyzed.

RESULTS

Six patients were affected by neurofibromatosis or schwannomatosis. There were 14 schwannomas, 8 neurofibromas, 1 myxoma, 1 reactive follicular hyperplasia, and 1 giant cell tumor of tendon sheath. No patient experienced worsening of neurological status after surgery. No side effects related to fluorescein injection were found in this series. Fluorescein allowed an optimal intraoperative distinction between tumor and surrounding nerves in 13 of 14 schwannomas and in all neurofibromas. In 6 neurofibromas and in 1 schwannoma, the final YELLOW 560 visualization showed the presence of small tumor remnants that were not visible under white-light illumination and that could be removed, obtaining a gross-total resection.

CONCLUSIONS

Fluorescein was demonstrated to be a feasible, safe, and helpful intraoperative adjunct to better identify and distinguish PNSTs from intact functional nerves, with a possible impact on tumor resection, particularly in diffuse neurofibromas.

OBJECTIVE

Clinical evidence on giant intracranial aneurysms (GIAs), intracranial aneurysms with a diameter of at least 25 mm, is limited. The authors aimed to investigate the natural history, case fatality, and treatment outcomes of ruptured and unruptured GIAs.

METHODS

In this international observational registry study, patients with a ruptured or unruptured GIA received conservative management (CM), surgical management (SM), or endovascular management (EM). The authors investigated rupture rates and case fatality.

RESULTS

The retrospective cohort comprised 219 patients with GIAs (21.9% ruptured GIAs and 78.1% unruptured GIAs) whose index hospitalization occurred between January 2006 and November 2016. The index hospitalization in the prospective cohort (362 patients with GIAs [17.1% ruptured and 82.9% unruptured]) occurred between December 2008 and February 2017. In the retrospective cohort, the risk ratio for death at a mean follow-up of 4.8 years (SD 2.2 years) after CM, compared with EM and SM, was 1.63 (95% CI 1.23–2.16) in ruptured GIAs and 3.96 (95% CI 2.57–6.11) in unruptured GIAs. In the prospective cohort, the 1-year case fatality in ruptured GIAs/unruptured GIAs was 100%/22.0% during CM, 36.0%/3.0% after SM, and 39.0%/12.0% after EM. Corresponding 1-year rupture rates in unruptured GIAs were 25.0% during CM, 1.2% after SM, and 2.5% after EM. In unruptured GIAs, the HR for death within the 1st year in patients with posterior circulation GIAs was 6.7 (95% CI 1.5–30.4, p < 0.01), with patients with a GIA at the supraclinoid internal carotid artery as reference. Different sizes of unruptured GIAs were not associated with 1-year case fatality.

CONCLUSIONS

Rupture rates for unruptured GIAs were high, and the natural history and treatment outcomes for ruptured GIAs were poor. Patients undergoing SM or EM showed lower case fatality and rupture rates than those undergoing CM. This difference in outcome may in part be influenced by patients in the CM group having been found poor candidates for SM or EM.

Clinical trial registration no.: NCT02066493 (clinicaltrials.gov)

OBJECTIVE

Previous authors have investigated many factors that predict an academic neurosurgical career over private practice, including attainment of a Doctor of Philosophy (PhD) and number of publications. Research has yet to demonstrate whether a master’s degree predicts an academic neurosurgical career. This study quantifies the association between obtaining a Master of Science (MS), Master of Public Health (MPH), or Master of Business Administration (MBA) degree and pursuing a career in academic neurosurgery.

METHODS

Public data on neurosurgeons who had graduated from Accreditation Council for Graduate Medical Education (ACGME)–accredited residency programs in the period from 1949 to 2019 were collected from residency and professional websites. Residency graduates with a PhD were excluded to isolate the effect of only having a master’s degree. A position was considered “academic” if it was affiliated with a hospital that had a neurosurgery residency program; other positions were considered nonacademic. Bivariate analyses were performed with Fisher’s exact test. Multivariate analysis was performed using a logistic regression model.

RESULTS

Within our database of neurosurgery residency alumni, there were 47 (4.1%) who held an MS degree, 31 (2.7%) who held an MPH, and 10 (0.9%) who held an MBA. In bivariate analyses, neurosurgeons with MS degrees were significantly more likely to pursue academic careers (OR 2.65, p = 0.0014, 95% CI 1.40–5.20), whereas neurosurgeons with an MPH (OR 1.41, p = 0.36, 95% CI 0.64–3.08) or an MBA (OR 1.00, p = 1.00, 95% CI 0.21–4.26) were not. In the multivariate analysis, an MS degree was independently associated with an academic career (OR 2.48, p = 0.0079, 95% CI 1.28–4.93). Moreover, postresidency h indices of 1 (OR 1.44, p = 0.048, 95% CI 1.00–2.07), 2–3 (OR 2.76, p = 2.01 × 10⁻⁸, 95% CI 1.94–3.94), and ≥ 4 (OR 4.88, p < 2.00 × 10⁻¹⁶, 95% CI 3.43–6.99) were all significantly associated with increased odds of pursuing an academic career. Notably, having between 1 and 11 months of protected research time was significantly associated with decreased odds of pursuing academic neurosurgery (OR 0.46, p = 0.049, 95% CI 0.21–0.98).

CONCLUSIONS

Neurosurgery residency graduates with MS degrees are more likely to pursue academic neurosurgical careers relative to their non-MS counterparts. Such findings may be used to help predict residency graduates’ future potential in academic neurosurgery.

OBJECTIVE

The endovascular treatment of complex bifurcation aneurysms possessing a neck that incorporates multiple side branches remains a surgical challenge. Double-stent–assisted coiling techniques, such as those with stents in an X and Y configuration, enable the endovascular treatment of wide-necked complex intracranial bifurcation aneurysms. However, the intraluminal struts at the intersection point in X- and Y-stents are not amenable to endothelialization, which may lead to thromboembolic complications. Stenting in the T configuration is a relatively new double-stent coiling technique. T-stenting differs from X- or Y-stenting in that there are no overlapping or intersecting stent segments. Promising short-term results of T-stent–assisted coiling were recently reported. However, the long-term results have not yet been demonstrated. This retrospective study investigated the long-term angiographic and clinical results in patients with wide-necked complex intracranial bifurcation aneurysms treated with T-stent–assisted coiling.

METHODS

A retrospective review was performed to identify patients with wide-necked complex intracranial bifurcation aneurysms treated with T-stent–assisted coiling at 4 institutions. The technical success and the initial and follow-up clinical and angiographic outcomes were assessed. Aneurysm filling status was assessed according to the Raymond classification. Periprocedural and delayed complications were reviewed. The neurological status of the patients was evaluated using the modified Rankin Scale (mRS).

RESULTS

One hundred two aneurysms in 102 patients (54 females), whose mean age was 57.9 ± 13.0 years, were included in the study. T-stenting was performed successfully in all patients. Immediate postprocedural angiography revealed complete occlusion in 83.3% of patients. Periprocedural complications developed in 13.7%, resulting in permanent morbidity in 1.9% and death in 1%. Eighty patients (78.4%) had at least one follow-up DSA examination performed at 6 months or later following the endovascular procedure. The mean duration of angiographic follow-up was 30.0 ± 16.3 months. The last follow-up examinations showed complete occlusion in 90.0% of patients. During the follow-up period, only 1 patient (1.3%) required retreatment. Delayed thromboembolic complications were observed in 4 patients (3.9%) without permanent morbidity. The mRS scores of all patients at the last clinical follow-up were between 0 and 2.

CONCLUSIONS

The short-term angiographic findings showed that T-stent–assisted coiling is a feasible and effective endovascular method to treat wide-necked complex bifurcation aneurysms. The long-term angiographic follow-up results suggest that T-stent–assisted coiling provides a durable treatment for wide-necked complex bifurcation aneurysms with favorable clinical outcomes, demonstrating the long-term safety of T-stent–assisted coiling.