Probabilistic Presurgical Language Functional MRI Atlas of Brain Tumor Patients.

BACKGROUND AND PURPOSE: Patients with brain tumors have high intersubject variation in putative language regions, which may limit the utility of straightforward application of healthy-subject brain atlases in clinical scenarios. The purpose of this study was to develop a probabilistic functional brain atlas that consolidates language functional activations of sentence completion and silent word generation language paradigms using a large sample of patients with brain tumors. MATERIALS AND METHODS: The atlas was developed using retrospectively collected fMRI data from patients with brain tumors who underwent their first standard-of-care presurgical language fMRI scan at our institution between July 18, 2015, and May 13, 2022. 317 patients (861 fMRI scans) were used to develop the language functional atlas. An independent presurgical language fMRI dataset of 39 patients with brain tumors from a previous study was used to evaluate our atlas. Family-wise error corrected binary functional activation maps from sentence completion, letter fluency, and category fluency presurgical fMRI were used to create probability overlap maps and pooled probabilistic overlap map in Montreal Neurological Institute standard space. Wilcoxon signed-rank test was used to determine significant difference in the maximum Dice coefficient for our atlas compared to a meta-analysis-based template with respect to expert-delineated primary language area activations. RESULTS: Probabilities of activating left anterior primary language area and left posterior primary language area in temporal lobe were 87.9% and 91.5%, respectively, for sentence completion, 88.5% and 74.2%, respectively, for letter fluency, and 83.6% and 67.6%, respectively, for category fluency. Maximum Dice coefficients for templates derived from our language atlas were significantly higher than the meta-analysis-based template in left anterior primary language area (0.351 and 0.326, respectively, P < .05) and left posterior primary language area in temporal lobe (0.274 and 0.244, respectively, P < .005). CONCLUSIONS: Brain tumor patient-and paradigm-specific probabilistic language atlases were developed. These atlases had superior spatial agreement with fMRI activations in individual patients than the meta-analysis-based template. ABBREVIATIONS: SENT = sentence completion, LETT = letter fluency, CAT = category fluency, PLA = primary language area, aPLA = anterior PLA, pPLAT = posterior PLA in the temporal lobe, pPLAP = posterior PLA in the parietal lobe, SMA = supplementary motor area, DLPFC = dorsolateral prefrontal cortex, BTLA = basal temporal language area.

Comparative analysis of brain language templates with primary language areas detected from presurgical fMRI of brain tumor patients.

INTRODUCTION: Functional brain templates are often used in the analysis of clinical functional MRI (fMRI) studies. However, these templates are mostly built based on anatomy or fMRI of healthy subjects, which have not been fully vetted in clinical cohorts. Our aim was to evaluate language templates by comparing with primary language areas (PLAs) detected from presurgical fMRI of brain tumor patients. METHODS: Four language templates (A-D) based on anatomy, task-based fMRI, resting-state fMRI, and meta-analysis, respectively, were compared with PLAs detected by fMRI with word generation and sentence completion paradigms. For each template, the fraction of PLA activations enclosed by the template (positive inclusion fraction, [PIF]), the fraction of activations within the template but that did not belong to PLAs (false inclusion fraction, [FIF]), and their Dice similarity coefficient (DSC) with PLA activations were calculated. RESULTS: For anterior PLAs, Template A had the greatest PIF (median, 0.95), whereas Template D had both the lowest FIF (median, 0.074), and the highest DSC (median, 0.30), which were all significant compared to other templates. For posterior PLAs, Templates B and D had similar PIF (median, 0.91 and 0.90, respectively) and DSC (both medians, 0.059), which were all significantly higher than that of Template C. Templates B and C had significantly lower FIF (median, 0.061 and 0.054, respectively) compared to Template D. CONCLUSION: This study demonstrated significant differences between language templates in their inclusiveness of and spatial agreement with the PLAs detected in the presurgical fMRI of the patient cohort. These findings may help guide the selection of language templates tailored to their applications in clinical fMRI studies.

Response of treatment-naive brain metastases to stereotactic radiosurgery.

With improvements in survival for patients with metastatic cancer, long-term local control of brain metastases has become an increasingly important clinical priority. While consensus guidelines recommend surgery followed by stereotactic radiosurgery (SRS) for lesions >3 cm, smaller lesions (≤3 cm) treated with SRS alone elicit variable responses. To determine factors influencing this variable response to SRS, we analyzed outcomes of brain metastases ≤3 cm diameter in patients with no prior systemic therapy treated with frame-based single-fraction SRS. Following SRS, 259 out of 1733 (15%) treated lesions demonstrated MRI findings concerning for local treatment failure (LTF), of which 202 /1733 (12%) demonstrated LTF and 54/1733 (3%) had an adverse radiation effect. Multivariate analysis demonstrated tumor size (>1.5 cm) and melanoma histology were associated with higher LTF rates. Our results demonstrate that brain metastases ≤3 cm are not uniformly responsive to SRS and suggest that prospective studies to evaluate the effect of SRS alone or in combination with surgery on brain metastases ≤3 cm matched by tumor size and histology are warranted. These studies will help establish multi-disciplinary treatment guidelines that improve local control while minimizing radiation necrosis during treatment of brain metastasis ≤3 cm.

Short-term predictors of stereotactic radiosurgery outcome for untreated single non-small cell lung cancer brain metastases: a restrospective cohort study.

Stereotactic radiosurgery (SRS) is an option for brain metastases (BM) not eligible for surgical resection, however, predictors of SRS outcomes are poorly known. The aim of this study is to investigate predictors of SRS outcome in patients with BM secondary to non-small cell lung cancer (NSCLC). The secondary objective is to analyze the value of volumetric criteria in identifying BM progression. This retrospective cohort study included patients >18 years of age with a single untreated BM secondary to NSCLC. Demographic, clinical, and radiological data were assessed. The primary outcome was treatment failure, defined as a BM volumetric increase 12 months after SRS. The unidimensional measurement of the BM at follow-up was also assessed. One hundred thirty-five patients were included, with a median BM volume at baseline of 1.1 cm3 (IQR 0.4-2.3). Fifty-two (38.5%) patients had SRS failure at follow-up. Only right BM laterality was associated with SRS failure (p=0.039). Using the volumetric definition of SRS failure, the unidimensional criteria demonstrated a sensibility of 60.78% (46.11%-74.16%), specificity of 89.02% (80.18%-94.86%), positive LR of 5.54 (2.88-10.66) and negative LR of 0.44 (0.31-0.63). SRS demonstrated a 61.5% local control rate 12 months after treatment. Among the potential predictors of treatment outcome analyzed, only the right BM laterality had a significant association with SRS failure. The volumetric criteria were able to identify more subtle signs of BM increase than the unidimensional criteria, which may allow earlier diagnosis of disease progression and use of appropriate therapies.

Laser interstitial thermal therapy for new and recurrent meningioma: a prospective and retrospective case series.

OBJECTIVE: Meningiomas are the most common primary brain tumors in adults and a subset are aggressive lesions resistant to standard therapies. Laser interstitial thermal therapy (LITT) has been successfully applied to other brain tumors, and recent work aims to explore the safety and long-term outcome experiences of LITT for both new and recurrent meningiomas. The authors' objective was to report safety and outcomes data of the largest cohort of LITT-treated meningioma patients to date. METHODS: Eight United States-based hospitals enrolled patients with meningioma in the Laser Ablation of Abnormal Neurological Tissue Using Robotic NeuroBlate System (LAANTERN) prospective multicenter registry and/or contributed additional retrospective enrollments for this cohort study. Demographic, procedural, safety, and outcomes data were collected and analyzed using standard statistical methods. RESULTS: Twenty adult patients (12 prospective and 8 retrospective) with LITT-targeted meningiomas were accrued. Patients underwent LITT for new (6 patients) and recurrent (14 patients) tumors (ranging from the 1st to 12th recurrence). The 30-day complication rate was 10%. Twenty percent of patients (4/20) had exhausted all other treatment options. Median length of follow-up was 1.3 years. One-third of new (2/6) and one-half of recurrent (7/14) meningiomas had disease progression during follow-up. One-year estimated local control (LC), progression-free survival, and overall survival rates were 55.3%, 48.4%, and 86.3%, respectively. In the 12 patients who had ≥ 91% ablative coverage, 1-year estimated LC was 61.4%. The complication rate was 10% (2/20), with 1 complication being transient and resolving postoperatively. CONCLUSIONS: This cohort study supports the safety of the procedure for this tumor type. LITT can offer a much-needed treatment option, especially for patients with multiply recurrent meningiomas who have limited remaining alternatives.

Intraoperative language mapping guided by real-time visualization of gamma band modulation electrocorticograms: Case report and proof of concept.

Background: Electrocorticography (ECoG) language mapping is often performed extraoperatively, frequently involves offline processing, and relationships with direct cortical stimulation (DCS) remain variable. We sought to determine the feasibility and preliminary utility of an intraoperative language mapping approach guided by real-time visualization of electrocorticograms. Methods: A patient with astrocytoma underwent awake craniotomy with intraoperative language mapping, utilizing a dual iPad stimulus presentation system coupled to a real-time neural signal processing platform capable of both ECoG recording and delivery of DCS. Gamma band modulations in response to 4 language tasks at each electrode were visualized in real-time. Next, DCS was conducted for each neighboring electrode pair during language tasks. Results: All language tasks resulted in strongest heat map activation at an electrode pair in the anterior to mid superior temporal gyrus. Consistent speech arrest during DCS was observed for Object and Action naming tasks at these same electrodes, indicating good correspondence with ECoG heat map recordings. This region corresponded well with posterior language representation via preoperative functional MRI. Conclusions: Intraoperative real-time visualization of language task-based ECoG gamma band modulation is feasible and may help identify targets for DCS. If validated, this may improve the efficiency and accuracy of intraoperative language mapping.

Decoding the clinical effects of low-grade glioma-induced cortical excitability.

OBJECTIVE: Patients with low-grade glioma (LGG) in eloquent regions often present with seizures, and findings on detailed neuropsychological testing are often abnormal. This study evaluated the association between cortical excitability, seizures, and cognitive function in patients with LGG. METHODS: LGG patients who underwent transcranial magnetic stimulation (TMS) from January 2021 to December 2022 were studied. Cortical excitability was measured using the resting motor thresholds (RMTs) of the upper and lower extremities. Early postoperative seizures served as the seizure endpoint. Neuropsychological assessment was completed prior to surgery contemporaneous with the TMS studies. RESULTS: A total of 31 patients were analyzed for seizure outcome. Median (interquartile range [IQR]) upper-extremity RMT was 39% (34%-46%) of maximum stimulator output, and the median (IQR) lower-extremity RMT was 69% (51%-79%). Lower-extremity RMT was higher in patients with early postoperative seizures, especially in those with motor region tumors (p = 0.02); however, RMT was not associated with seizures at presentation or long-term seizure control. A total of 26 patients completed neuropsychological assessment. There were significant negative correlations between upper-extremity RMT and psychomotor processing speed (Wechsler Adult Intelligence Scale-Fourth Edition [WAIS-IV] Processing Speed Index r = -0.42, p = 0.031; WAIS-IV Coding r = -0.41, p = 0.036; WAIS-IV Symbol Search r = -0.39, p = 0.048), executive function (Trail Making Test Part B r = -0.41, p = 0.036), and hand dexterity (Grooved Pegboard Test r = -0.50, p = 0.047). CONCLUSIONS: RMT was positively correlated with early postoperative seizure risk and negatively correlated with psychomotor processing speed, executive function, and hand dexterity. These findings support the theory of local and regional resting oscillatory network dysfunction from a glioma-brain network.

Subependymomas of the fourth ventricle: To operate or not to operate?

BACKGROUND: There is a paucity of literature regarding the clinical characteristics and management of subependymomas of the fourth ventricle due to their rarity. Here, we describe the operative and non-operative management and outcomes of patients with such tumors. METHODS: This retrospective single-institution case series was gathered after Institutional Review Board (IRB) approval. Patients diagnosed with a subependymoma of the fourth ventricle between 1993 and 2021 were identified. Clinical, radiology and pathology reports along with magnetic resonance imaging (MRI) images were reviewed. RESULTS: Patients identified (n = 20), showed a male predominance (n = 14). They underwent surgery (n = 9) with resection and histopathological confirmation of subependymoma or were followed with imaging surveillance (n = 11). The median age at diagnosis was 51.5 years. Median tumor volume for the operative cohort was 8.64 cm3 and median length of follow-up was 65.8 months. Median tumor volume for the non-operative cohort was 0.96 cm3 and median length of follow-up was 78 months. No tumor recurrence post-resection was noted in the operative group, and no tumor growth from baseline was noted in the non-operative group. Most patients (89 %) in the operative group had symptoms at diagnosis, all of which improved post-resection. No patients were symptomatic in the non-operative group. CONCLUSIONS: Surgical resection is safe and is associated with alleviation of presenting symptoms in patients with large tumors. Observation and routine surveillance are warranted for smaller, asymptomatic tumors.

Lateral ventricle subependymoma resected with a transcallosal approach: illustrative case.

BACKGROUND: Subependymomas are World Health Organization grade I tumors, and 30% occur in the lateral ventricles. Surgery is the mainstay of treatment, and the transcallosal or transcortical/transsulcal approaches are preferred for those tumors occurring near the foramen of Monro or atrium. Visualization, proximity to the fornix and basal ganglia, hydrocephalus, and brain retraction during surgery make these operations challenging. The authors present the case of a 65-year-old male with a subependymoma located in the left lateral ventricle. The tumor was completely resected using an interhemispheric/transcallosal approach. OBSERVATIONS: The authors analyze the anatomopathological features of subependymoma, along with the clinical behavior and therapeutic options. The authors discuss in detail the advantages and disadvantages of the interhemispheric/transcallosal approach for resection of these tumors. LESSONS: Subependymomas are slow-growing lesions with an indolent yet complicated course making surgical removal challenging yet feasible using the correct techniques. The interhemispheric transcallosal approach offers an excellent route for the resection of large subependymomas, but there is still a significant risk for postoperative complications.

Efficacy of laser interstitial thermal therapy for biopsy-proven radiation necrosis in radiographically recurrent brain metastases.

Background: Laser interstitial thermal therapy (LITT) in the setting of post-SRS radiation necrosis (RN) for patients with brain metastases has growing evidence for efficacy. However, questions remain regarding hospitalization, local control, symptom control, and concurrent use of therapies. Methods: Demographics, intraprocedural data, safety, Karnofsky performance status (KPS), and survival data were prospectively collected and then analyzed on patients who consented between 2016-2020 and who were undergoing LITT for biopsy-proven RN at one of 14 US centers. Data were monitored for accuracy. Statistical analysis included individual variable summaries, multivariable Fine and Gray analysis, and Kaplan-Meier estimated survival. Results: Ninety patients met the inclusion criteria. Four patients underwent 2 ablations on the same day. Median hospitalization time was 32.5 hours. The median time to corticosteroid cessation after LITT was 13.0 days (0.0, 1229.0) and cumulative incidence of lesional progression was 19% at 1 year. Median post-procedure overall survival was 2.55 years [1.66, infinity] and 77.1% at one year as estimated by KaplanMeier. Median KPS remained at 80 through 2-year follow-up. Seizure prevalence was 12% within 1-month post-LITT and 7.9% at 3 months; down from 34.4% within 60-day prior to procedure. Conclusions: LITT for RN was not only again found to be safe with low patient morbidity but was also a highly effective treatment for RN for both local control and symptom management (including seizures). In addition to averting expected neurological death, LITT facilitates ongoing systemic therapy (in particular immunotherapy) by enabling the rapid cessation of steroids, thereby facilitating maximal possible survival for these patients.

Predictors of Survival After Stereotactic Radiosurgery for Untreated Single Non-Small Cell Lung Cancer Brain Metastases: 5- and 10-year Results.

BACKGROUND: Stereotactic radiosurgery (SRS) presents as a good treatment option for smaller, deep-seated brain metastases (BMs). This study aims to determine predictors of SRS failure for patients with non-small cell lung cancer BMs. METHODS: This was a retrospective study of single non-small cell lung cancer BMs treated using SRS. We included patients >18 years with a single, previously untreated lesion. Primary outcome was treatment failure, defined as BMs dimension increase above the initial values. Demographic, clinical, and radiological data were collected to study potential predictors of treatment failure. RESULTS: Worse rates of progression-free survival (PFS) were associated with heterogeneous contrast enhancement (18.1 ± 4.1 vs. 41.9 ± 4 months; P < 0.001). Better rates of PFS were associated with volumes <1.06 cm3 (log-rank; P = 0.001). Graded prognostic assessment was significantly associated with survival at 120 months (log-rank; P < 0.001). Karnofsky Performance Scale was evaluated in 3 strata: 90-100, 80, and ≤70. Mean survival rates for these strata were 31.8 ± 3.9, 10.6 ± 2.2, and 9.8 ± 2.3 months, respectively (log-rank; P < 0.001). There were no differences regarding presence of extracranial metastases, age, or lesion location. A multivariable logistic regression found that volume <1.06 cm3 was associated with higher survival rates at 10 years (odds ratio: 3.2, 95% confidence interval: 1.3-8.0). CONCLUSIONS: Contrast-homogeneous metastases and lesions <1.06 cm3 are associated with better rates of PFS. Karnofsky Performance Scale and graded prognostic assessment were associated with more favorable survival rates after 10 years. Volume <1.06 cm3 was the only significant predictor of survival in the multivariable analysis.

Changes in outcomes and factors associated with survival in melanoma patients with brain metastases.

BACKGROUND: Treatment options for patients with melanoma brain metastasis (MBM) have changed significantly in the last decade. Few studies have evaluated changes in outcomes and factors associated with survival in MBM patients over time. The aim of this study is to evaluate changes in clinical features and overall survival (OS) for MBM patients. METHODS: Patients diagnosed with MBMs from 1/1/2009 to 12/31/2013 (Prior Era; PE) and 1/1/2014 to 12/31/2018 (Current Era; CE) at The University of Texas MD Anderson Cancer Center were included in this retrospective analysis. The primary outcome measure was OS. Log-rank test assessed differences between groups; multivariable analyses were performed with Cox proportional hazards models and recursive partitioning analysis (RPA). RESULTS: A total of 791 MBM patients (PE, n = 332; CE, n = 459) were included in analysis. Median OS from MBM diagnosis was 10.3 months (95% CI, 8.9-12.4) and improved in the CE vs PE (14.4 vs 10.3 months, P < .001). Elevated serum lactate dehydrogenase (LDH) was the only factor associated with worse OS in both PE and CE patients. Factors associated with survival in CE MBM patients included patient age, primary tumor Breslow thickness, prior immunotherapy, leptomeningeal disease, symptomatic MBMs, and whole brain radiation therapy. Several factors associated with OS in the PE were not significant in the CE. RPA demonstrated that elevated serum LDH and prior immunotherapy treatment are the most important determinants of survival in CE MBM patients. CONCLUSIONS: OS and factors associated with OS have changed for MBM patients. This information can inform contemporary patient management and clinical investigations.

Comparative study of preoperative functional imaging combined with tractography for prediction of iatrogenic motor deficits.

OBJECTIVE: Robust preoperative imaging can improve the extent of resection in patients with brain tumors while minimizing postoperative neurological morbidity. Both structural and functional imaging techniques can provide helpful preoperative information. A recent study found that transcranial magnetic stimulation (TMS) tractography has significant predictive value for permanent deficits. The present study directly compares the predictive value of TMS tractography and task-based functional MRI (fMRI) tractography in the same cohort of glioma patients. METHODS: Clinical outcome data were collected from charts of patients with motor eloquent glioma and preoperative fMRI and TMS studies. The primary outcome was a new or worsened motor deficit present at the 3-month postoperative follow-up, which was termed a "permanent deficit." Postoperative MR images were overlaid onto preoperative plans to determine which imaging features were resected. Multiple fractional anisotropic thresholds (FATs) were screened for both TMS and fMRI tractography. The predictive value of the various thresholds was modeled using receiver operating characteristic curve analysis. RESULTS: Forty patients were included in this study. Six patients (15%) sustained permanent postoperative motor deficits. A significantly greater predictive value was found for TMS tractography than for fMRI tractography regardless of the FAT. Despite 35% of patients showing clinically relevant neuroplasticity captured by TMS, only 2.5% of patients showed a blood oxygen level-dependent signal displaced from the precentral gyrus. Comparing the best-performing FAT for both modalities, TMS seeded tractography showed superior predictive value across all metrics: sensitivity, specificity, positive predictive value, and negative predictive value. CONCLUSIONS: The results from this study indicate that the prediction of permanent deficits with TMS tractography is superior to that with fMRI tractography, possibly because TMS tractography captures clinically relevant neuroplasticity. However, future large-scale prospective studies are needed to fully illuminate the proper role of each modality in comprehensive presurgical workups for patients with motor-eloquent tumors.

Long-latency gamma modulation after median nerve stimulation delineates the central sulcus and contrasts the states of consciousness.

OBJECTIVE: To evaluate the functional use of sub-band modulations in somatosensory evoked potentials (SSEPs) to discriminate between the primary somatosensory (S1) and motor (M1) areas and contrast the states of consciousness. METHODS: During routine intraoperative cortical mapping, SSEPs were recorded with electrocorticography (ECoG) grids from the sensorimotor cortex of eight patients in the anesthetized and awake states. We conducted a time-frequency analysis on the SSEP trace to extract the spectral modulations in each state and visualize their spatial topography. RESULTS: We observed late gamma modulation (60-250 Hz) in all subjects approximately 50 ms after stimulation onset, extending up to 250 ms in each state. The late gamma activity enhancement was predominant in S1 in the awake state, where it discriminated S1 from M1 at a higher accuracy (92 %) than in the anesthetized state (accuracy = 70 %). CONCLUSIONS: These results showed that sensorimotor mapping does not need to rely on only SSEP phase reversal. The long latency gamma modulation can serve as a biomarker for primary sensorimotor localization and monitor the level of consciousness in neurosurgical practice. SIGNIFICANCE: While the intraoperative assessment of SSEP phase reversal with ECoG is widely employed to delineate the central sulcus, the median nerve stimulation-induced spatio-spectral patterns can distinctly localize it and distinguish between conscious states.

Transcranial magnetic stimulation tractography and the facilitation of gross total resection in a patient with a motor eloquent glioblastoma: illustrative case.

BACKGROUND: In patients with perieloquent tumors, neurosurgeons must use a variety of techniques to maximize survival while minimizing postoperative neurological morbidity. Recent publications have shown that conventional anatomical features may not always predict postoperative deficits. Additionally, scientific conceptualizations of complex brain function have shifted toward more dynamic, neuroplastic theories instead of traditional static, localizationist models. Functional imaging techniques have emerged as potential tools to incorporate these advances into modern neurosurgical care. In this case report, we describe our observations using preoperative transcranial magnetic stimulation data combined with tractography to guide a nontraditional surgical approach in a patient with a motor eloquent glioblastoma. OBSERVATIONS: The authors detail the use of preoperative functional and structural imaging to perform a gross total resection despite tumor infiltration of conventionally eloquent anatomical structures. The authors resected the precentral gyrus, specifically the paracentral lobule, localized using intraoperative mapping techniques. The patient demonstrated mild transient postoperative weakness and made a full neurological recovery by discharge 1 week later. LESSONS: Preoperative functional and structural imaging has potential to not only optimize patient selection and surgical planning, but also facilitate important intraoperative decisions. Innovative preoperative imaging techniques should be optimized and used to identify safely resectable structures.

Real-Time Delineation of the Central Sulcus with the Spatial Profile of SSEPs Captured with High-Density Ecog Grid.

Cortical mapping is widely employed to define the sensorimotor area and delineate the central sulcus (CS) during awake craniotomies. The approach involves the gold standard somatosensory evoked potentials (SSEPs) recorded with electrocorticogram (ECoG) strip electrodes. However, the evoked response can be misconstrued from the manual peak interpretation due to the poor spatial resolution of the strip electrode or when the electrode does not precisely cover the desired cortical area. This can lead to unintentional damage to the eloquent cortex. We present a soft real-time computer based visualization system that uses recorded SSEPs with a subdural grid to aid in cortical mapping. The neural data during electrical stimulation of the median nerve at 0.6Hz are picked up with a bio-amplifier at 2.4kHz. The stimulation artifact recorded from the bipolar electromyogram (EMG) is used as the stimulation onset. The ECoG data are assessed online with MATLAB Simulink to process and visualize the SSEPs waveform. The visualization system is programmed to display the SSEPs peak activation as a heat map on a 2D grid and projected onto a screen, showcasing the nature of the cortical activities over the contact surface area. Since the grid occupies a large cortical surface, the heatmap is able to delineate the central sulcus. The map can be viewed at any time point along the SSEP trace without the need for peak interpretation. With the goal to provide additional information during cortical mapping and facilitate interpretation of ECoG grid data, we believe that this visualization system will aid in rapid definition of the sensorimotor area during surgical planning. Clinical Relevance- This real-time visualization system can be used to delineate the central sulcus in a short time during awake craniotomies.

Patterns of failure after radiation therapy in primary spinal high-grade gliomas: A single institutional analysis.

Background: Primary spinal high-grade gliomas (S-HGG) are rare aggressive tumors; radiation therapy (RT) often plays a dominant role in management. We conducted a single-institution retrospective review to study the clinicopathological features and management of S-HGGs. Methods: Patients with biopsy-proven S-HGG who received RT from 2001 to 2020 were analyzed for patient, tumor, and treatment characteristics. Kaplan-Meier estimates were used for survival analyses. Results: Twenty-nine patients were identified with a median age of 25.9 years (range 1-74 y). Four patients had GTR while 25 underwent subtotal resection or biopsy. All patients were IDH wildtype and MGMT-promoter unmethylated, where available. H3K27M mutation was present in 5 out of 10 patients tested, while one patient harbored p53 mutation. Median RT dose was 50.4 Gy (range 39.6-54 Gy) and 65% received concurrent chemotherapy, most commonly temozolomide. Twenty-three (79%) of patients had documented recurrence. Overall, 16 patients relapsed locally, 10 relapsed in the brain and 8 developed leptomeningeal disease; only 8 had isolated local relapse. Median OS from diagnosis was 21.3 months and median PFS was 9.7 months. On univariate analysis, age, gender, GTR, grade, RT modality, RT dose and concurrent chemotherapy did not predict for survival. Patients with H3K27M mutation had a poorer PFS compared to those without mutation (10.1 m vs 45.1 m) but the difference did not reach statistical significance (P = .26). Conclusions: The prognosis of patients with spinal HGGs remains poor with two-thirds of the patients developing distant recurrence despite chemoradiation. Survival outcomes were similar in patients ≤ 29 years compared to adults > 29 years. A better understanding of the molecular drivers of spinal HGGs is needed to develop more effective treatment options.

Transcranial magnetic stimulation (TMS) seeded tractography provides superior prediction of eloquence compared to anatomic seeded tractography.

Background: For patients with brain tumors, maximizing the extent of resection while minimizing postoperative neurological morbidity requires accurate preoperative identification of eloquent structures. Recent studies have provided evidence that anatomy may not always predict eloquence. In this study, we directly compare transcranial magnetic stimulation (TMS) data combined with tractography to traditional anatomic grading criteria for predicting permanent deficits in patients with motor eloquent gliomas. Methods: We selected a cohort of 42 glioma patients with perirolandic tumors who underwent preoperative TMS mapping with subsequent resection and intraoperative mapping. We collected clinical outcome data from their chart with the primary outcome being new or worsened motor deficit present at 3 month follow up, termed "permanent deficit". We overlayed the postoperative resection cavity onto the preoperative MRI containing preoperative imaging features. Results: Almost half of the patients showed TMS positive points significantly displaced from the precentral gyrus, indicating tumor induced neuroplasticity. In multivariate regression, resection of TMS points was significantly predictive of permanent deficits while the resection of the precentral gyrus was not. TMS tractography showed significantly greater predictive value for permanent deficits compared to anatomic tractography, regardless of the fractional anisotropic (FA) threshold. For the best performing FA threshold of each modality, TMS tractography provided both higher positive and negative predictive value for identifying true nonresectable, eloquent cortical and subcortical structures. Conclusion: TMS has emerged as a preoperative mapping modality capable of capturing tumor induced plastic reorganization, challenging traditional presurgical imaging modalities.