Magnetic resonance radiomics-derived sphericity correlates with seizure in brain arteriovenous malformations.

OBJECTIVES: Angioarchitectural analysis of brain arteriovenous malformations (BAVMs) is qualitative and subject to interpretation. This study quantified the morphology of and signal changes in the nidal and perinidal areas by using MR radiomics and compared the performance of MR radiomics and angioarchitectural analysis in detecting epileptic BAVMs. MATERIALS AND METHODS: From 2010 to 2020, a total of 111 patients with supratentorial BAVMs were retrospectively included and grouped in accordance with the initial presentation of seizure. Patients' angiograms and MR imaging results were analyzed to determine the corresponding angioarchitecture. The BAVM nidus was contoured on time-of-flight MR angiography images. The perinidal brain parenchyma was contoured on T2-weighted images, followed by radiomic analysis. Logistic regression analysis was performed to determine the independent risk factors for seizure. ROC curve analysis, decision curve analysis (DCA), and calibration curve were performed to compare the performance of angioarchitecture-based and radiomics-based models in diagnosing epileptic BAVMs. RESULTS: In multivariate analyses, low sphericity (OR: 2012.07, p = .04) and angiogenesis (OR: 5.30, p = .01) were independently associated with a high risk of seizure after adjustment for age, sex, temporal location, and nidal volume. The AUC for the angioarchitecture-based, MR radiomics-based, and combined models was 0.672, 0.817, and 0.794, respectively. DCA confirmed the clinical utility of the MR radiomics-based and combined models. CONCLUSIONS: Low nidal sphericity and angiogenesis were associated with high seizure risk in patients with BAVMs. MR radiomics-derived tools may be used for noninvasive and objective measurement for evaluating the risk of seizure due to BAVM. CLINICAL RELEVANCE STATEMENT: Low nidal sphericity was associated with high seizure risk in patients with brain arteriovenous malformation and MR radiomics may be used as a noninvasive and objective measurement method for evaluating seizure risk in patients with brain arteriovenous malformation. KEY POINTS: • Low nidal sphericity was associated with high seizure risk in patients with brain arteriovenous malformation. • The performance of MR radiomics in detecting epileptic brain arteriovenous malformations was more satisfactory than that of angioarchitectural analysis. • MR radiomics may be used as a noninvasive and objective measurement method for evaluating seizure risk in patients with brain arteriovenous malformation.

An optimization model for reducing thrombectomy center rotations while maintaining medical accessibility.

BACKGROUND/PURPOSE: This study addresses the delicate balance between healthcare personnel burnout and medical accessibility in the context of endovascular thrombectomy (EVT) services in urban areas. We aimed to determine the minimum number of hospitals providing EVT on rotation each day without compromising patient access. METHODS: Employing an optimization model, we developed shift schedules based on patient coverage rates and volumes during the pre-pandemic (2016-2018) and pandemic (2019-2021) periods. Starting with a minimum of two hospitals on duty per day, we gradually increased to a maximum of eight. Patient coverage rates, defined as the proportion of patients meeting bypass criteria and transported to rotating hospitals capable of EVT, were the primary outcomes. Sensitivity analyses explored the impact of varying patient transport intervals and accumulating patients over multiple years. RESULTS: Results from 7024 patient records revealed patient coverage rates of 92.5% (standard deviation [SD] 2.8%) during the pre-pandemic and 91.4% (SD 2.8%) during the pandemic, with at least two rotating hospitals daily. No significant differences were observed between schedules based on the highest patient volume and coverage rate months. A patient coverage rate of 98.99% was achieved with four rotating hospitals per day during the pre-pandemic period, with limited improvement beyond this threshold. Changing patient transport intervals and accumulating patients over six years (p = 0.83) had no significant impact on coverage rates. CONCLUSION: Our optimization model supports reducing the number of daily rotating hospitals by half while preserving a balance between patient accessibility and alleviating strain on medical teams.

Stereotactic radiosurgery for pituitary and cavernous sinus metastases.

PURPOSE: Metastases extending to the pituitary gland and cavernous sinus are extremely rare; however, advances in neuroimaging have increased the reported incidence. Stereotactic radiosurgery (SRS) affords the precise delivery of focused radiation to minimize adverse radiation effects. This study assessed the efficacy and safety of SRS in the treatment of pituitary and cavernous sinus metastases. METHODS: Analysis was performed on 23 patients with pituitary and cavernous sinus metastases who underwent treatment using SRS between 1996 and 2021. The cohort was categorized into 2 groups in terms of metastasis location: pituitary involvement (Group 1, n = 11) and cavernous sinus involvement (Group 2, n = 12). Overall survival, local tumor control, and distal tumor control rates were compared between the two groups using Kaplan-Meier analysis. RESULTS: The median age of the cohort was 52.2 years and the median tumor volume was 4.5 mL. Overall survival rates were as follows: 1 year (72.9%), 2 years (51.8%), and 3 years (45.3%). Local tumor control rates were as follows: 1 year (82.3%), 2 years (82.3%), and 3 years (65.9%). Visual deficit and hypopituitarism were the most common presentations in Group 1, whereas cranial nerve deficit was the most common presentation in Group 2. CONCLUSIONS: SRS appears to be a safe and effective therapy for the treatment of pituitary and cavernous sinus metastases. GKRS is a relatively simple procedure, which places minimal stress on the patient, thereby facilitating further anti-cancer treatment. Considering the limited survival duration in cases of metastasis, it is very likely that post-GKRS complications (e.g., new onset cranial nerve deficit and hypopituitarism) would not become an issue before patient passes away.

Magnetic resonance imaging signal characteristics associated with prognosis of skull base chordoma after gamma knife radiosurgery.

OBJECTIVE: To investigate the association between the magnetic resonance imaging (MRI) signal characteristics of skull base chordoma and radiosurgical outcomes. METHODS: Twenty-four patients with skull base chordomas treated with Gamma Knife radiosurgery (GKRS) after previous surgical resection were retrospectively (2001-2021) examined. Pre-GKRS MRIs were analyzed for RT2 (tumor-to-brainstem signal intensity ratio on T2-weighted imaging), RCE (tumor-to-brainstem signal intensity ratio on contrast-enhanced T1-weighted imaging), and mean apparent diffusion coefficient (ADC). Correlations of the parameters with patient survival and local tumor progression were made by using Cox regression and Kaplan-Meier analyses. RESULTS: During a median follow-up of 46 months after GKRS, 9 patients died with significantly more local tumor progression events (median number: 2 vs 0, P = .012) than did 15 alive patients. On multivariable analysis, higher mean ADC was associated with longer patient survival (P = .016) after GKRS. The actuarial 5-year overall survival rates were 88.9% versus 54.7% for chordomas with an ADC of ≥ 1270 × 10-6 mm2/s versus < 1270 × 10-6 mm2/s. RT2 < 1.5 (P = .038) and RCE > 1.57 (P = .022) were associated with a lower probability of local tumor control. CONCLUSION: Lower mean ADC values are associated with shorter patient survival in skull base chordomas after GKRS. Diffusion-weighted imaging may help in GKRS planning and outcome prediction for these patients.

Improved survival and intracranial tumor control of EGFR-mutated NSCLC patients with newly developed brain metastases following stereotactic radiosurgery and EGFR-TKI: a large retrospective cohort study and meta-analyses.

PURPOSE: To examine the differential effects of SRS and TKI on EGFR-mutated NSCLC patients with brain metastases (BMs) and outcomes following continuation of the same TKI agent in case of new BMs. METHODS: This study included 608 NSCLC patients (2,274 BMs) while meta-analyses included 1,651 NSCLC patients (> 3,944 BMs). Overall survival (OS) and intracranial progression free survival (iPFS) were estimated using Kaplan-Meier methods. Hazard ratios (95% CI) of prognostic factors were estimated using Cox regression models. RESULTS: The median OS/iPFS (95% CI) (months) for patients with wildtype EGFR/ALK, EGFR mutations, and ALK rearrangements were 17.7 (12.9-23.6)/12.1 (9.8-15.6), 28.9 (23.8-33.3)/17.7 (14.8-21.2), and 118.0 (not reached)/71.7 (15.1-not reached), respectively. In EGFR-mutated patients, meta-analyses combining our data showed significantly improved OS and iPFS of patients who received SRS and TKI (OS:35.1 months, iPFS:20.0 months) when compared to those who have SRS alone (OS:20.8 months, iPFS:11.8 months) or TKI alone (OS:24.3 months, iPFS:13.8 months). Having SRS for newly diagnosed BMs while keeping the existing TKI agent yielded OS (30.0 vs. 32.1 months, p = 0.200) non-inferior to patients who started combined SRS and TKI therapy for their newly diagnosed NSCLC with BMs. Multivariable analyses showed that good performance score and TKI therapy were associated with improved outcomes. CONCLUSIONS: Combined SRS and TKI resulted in favorable outcomes in EGFR-mutated NSCLC patients with newly diagnosed BMs. Continuation of the same TKI agent plus SRS in case of new brain metastases yielded good clinical outcomes and may be considered a standard-of-care treatment.

Leukoencephalopathy in patients with brain metastases who received radiosurgery with or without whole brain radiotherapy.

BACKGROUND: Whole brain radiation therapy (WBRT) for brain metastases (BMs) is a common cause of radiation-induced leukoencephalopathy; however the safety of alternative stereotactic radiosurgery (SRS) remains unclear. This study examined the incidence of leukoencephalopathy in patients treated with SRS alone versus WBRT plus SRS for BMs with a focus on the relationship between prognostic factors and leukoencephalopathy. METHODS: Analysis was performed between 2002 and 2021. The total enrollment was 993 patients with the distribution: WBRT plus SRS (n = 291) and SRS only (n = 702). Leukoencephalopathy was graded from 0 to 3 for changes in white matter indicated by the MRI after WBRT or SRS. Patient characteristics and SRS dosimetric parameters were reviewed to identify factors that contributed to the incidence of leukoencephalopathy or overall survival. RESULTS: The incidence of leukoencephalopathy was consistently higher in WBRT plus SRS group than in SRS alone group (p < 0.001). Leukoencephalopathy was also associated with a larger total tumor volume (≧28cm3; p = 0.028) and age (> 77 years; p = 0.025). Nonetheless, the SRS integral dose to skull in the subgroup of WBRT plus SRS treatment was not demonstrated significance in development of leukoencephalopathy (p = 0.986 for integral dose 1-2 J, p = 0.776 for integral dose > 2 J). CONCLUSIONS: This study revealed that SRS is safe for oligo-BMs in terms of leukoencephalopathy development. Patient age and total tumor volume were identified as important factors in assessing the development of leukoencephalopathy. The additional of SRS (even at an integral dose > 2 J) did not increase the incidence of leukoencephalopathy.

Natural history of lung squamous cell brain metastases in patients treated with radiosurgery: a thirty-year experience at a tertiary medical center.

PURPOSE: In this study we report our 30-year experience in stereotactic radiosurgery (SRS) treatment of lung squamous cell carcinoma (LUSC) brain metastases (BMs). It will serve to provide detailed longitudinal outcomes and predictors of efficacy in treating LUSC-BMs with SRS. METHOD: We retrospectively reviewed 51 patients and 109 tumors treated with SRS at our center between 1993 and 2022. Patient demographics, PDL1 genotype, immunotherapy use and mortality cause were recorded. Radiological and clinical outcomes were followed at 1-3-month intervals post-SRS. Cox-regression analysis and Kaplan-Meier survival curves were performed in statistical analysis. RESULTS: We included 37 male and 14 female patients (median age 62.7 years at BM diagnosis). Median overall survival (OS) time was 6.9 months, 6-month OS rate was 62.1%, and Karnofsky performance scale (KPS) was the only independent predictor. Median time for local control maintenance was 7.6 months, 6-month local control rate was 69.1%, with TKI as the only independent predictor. Median time to distant failure was 5.13 months, 6-month distant failure rate was 51.1%, and factors with significant impact included gender (p = 0.002), presence of extracranial metastases (p < 0.001), use of immunotherapy(p < 0.001), PDL1 genotype (p = 0.034), and total intracranial metastases number (p = 0.008). However, no definitive benefits of immunotherapy were identified in patients with higher PDL1 mutational tumors. CONCLUSION: In this study we defined the natural history of disease progression and outcomes in SRS-treated LUSC-BM patients. We also identified predictors of OS and tumor control among these patients. The findings of this study will serve as a guide when counseling these patients for SRS.

Is it advisable to perform radiosurgery for EGFR-TKI-controlled brain metastases? A retrospective study of the role of radiosurgery in lung cancer treatment.

PURPOSE: Given the availability of TKIs with high central nervous system efficacy, the question arises as to whether upfront SRS provides additional clinical benefits. The goal of this study was to characterize the clinical outcomes of SRS as salvage therapy for TKI-uncontrolled BMs. METHODS: This retrospective study included EGFR-mutant NSCLC patients presenting BMs at the time of primary tumor diagnosis. BMs were categorized into three subgroups, referred to as "Nature of TKI-treated BMs", "TKI-controlled brain metastases ± SRS", and "SRS salvage therapy". The first subgroup analysis characterized the effects of TKIs on tumor behavior. In the second subgroup, we compared outcomes of TKI-controlled BMs treated with TKI alone versus those treated with combined TKI-SRS therapy. The third subgroup characterized the outcomes of TKI-uncontrolled BMs treated with SRS as salvage therapy Clinical outcomes include local and distant tumor control. RESULTS: This study included 106 patients with a total of 683 BMs. TKI treatment achieved control in 63% of local tumors at 24 months. Among the TKI-controlled BMs, local tumor control was significantly higher in the combined TKI-SRS group (93%) than in the TKI-alone group (65%) at 24 months (p < 0.001). No differences were observed between the two groups in terms of distant tumor control (p = 0.832). In dealing with TKI-uncontrolled BMs, salvage SRS achieved local tumor control in 58% of BMs at 24 months. CONCLUSIONS: While upfront TKI alone proved highly effective in BM control, this study also demonstrated the outcomes of SRS when implemented concurrently with TKI or as salvage therapy for TKI-uncontrolled BMs. This study also presents a strategy of the precise timing and targeting of SRS to lesions in progression.

Noninvasive investigations of human glymphatic dynamics in a diseased model.

OBJECTIVES: To explore human glymphatic dynamics in a diseased model via a noninvasive technique. METHODS: Patients with reversible vasoconstriction syndrome (RCVS) presenting with blood-brain barrier disruption, i.e., para-arterial gadolinium leakage on 3-T 3-dimensional isotropic contrast-enhanced T2-fluid-attenuated inversion recovery (CE-T2-FLAIR) magnetic resonance imaging (MRI), were prospectively enrolled. Consecutive 9-min-CE-T2-FLAIR for 5-6 times (early panel) after intravenous gadolinium-based contrast agent (GBCA) administration and one time-varying deferred scan of noncontrast T2-FLAIR (delayed panel) were performed. In Bundle 1, we measured the calibrated signal intensities (cSIs) of 10 different anatomical locations. In Bundle 2, brain-wide measurements of para-arterial glymphatic volumes, means, and medians of the signal intensities were conducted. We defined mean (mCoIs) or median (mnCoIs) concentration indices as products of volumes and signal intensities. RESULTS: Eleven subjects were analyzed. The cSIs demonstrated early increase (9 min) in perineural spaces: (cranial nerve [CN] V, p = 0.008; CN VII + VII, p = 0.003), choroid plexus (p = 0.003), white matter (p = 0.004) and parasagittal dura (p = 0.004). The volumes, mCoIs, and mnCoIs demonstrated increasing rates of enhancement after 9 to 18 min and decreasing rates after 45 to 54 min. The GBCA was transported centrifugally and completely removed within 961-1086 min after administration. CONCLUSIONS: The exogenous GBCA leaked into the para-arterial glymphatics could be completely cleared around 961 to 1086 min after administration in a human model of BBB disruption. The tracer enhancement started variously in different intracranial regions but was eventually cleared centrifugally to brain convexity, probably towards glymphatic-meningeal lymphatics exits. CLINICAL RELEVANCE STATEMENT: Glymphatic clearance time intervals and the centrifugal directions assessed by a noninvasive approach may have implications for clinical glymphatic evaluation in the near future. KEY POINTS: • This study aimed to investigate the human glymphatic dynamics in a noninvasive diseased model. • The intracranial MR-detectable gadolinium-based contrast agents were removed centrifugally within 961 to 1086 min. • The glymphatic dynamics was demonstrable by enhancing MRI in an in vivo diseased model noninvasively.

Quantified flow and angioarchitecture show similar associations with hemorrhagic presentation of brain arteriovenous malformations.

INTRODUCTION: The purpose of our study was to elucidate the impact of brain arteriovenous malformation (BAVM) flow and wall shear stress (WSS) on angioarchitecture and to evaluate their association with hemorrhagic presentations. MATERIALS AND METHODS: Forty-one patients with BAVMs were evaluated by phase-contrast MR angiography. Volume flow rate and WSS were quantified. Angioarchitectural features such as location, angiogenesis, venous stenosis, venous ectasia, venous phlebitis, venous rerouting, exclusive deep vein and venous sac were evaluated by two neuroradiologists. The correlation between BAVM flow and size was evaluated with Spearman correlation coefficients. Differences of size, flow, and WSS between the hemorrhagic and non-hemorrhagic groups, the seizure and non-seizure groups, and between the different groups based on angioarchitecture were evaluated with Mann-Whitney U tests. Accuracy in predicting hemorrhage was evaluated with receiver operating characteristic curves. RESULT: BAVM flow was highly correlated with volume (ρ = 0.77). Higher flow was more commonly associated with angiogenesis, venous ectasia, venous rerouting, and venous phlebitis. Flow and angioarchitecture showed similar efficacy in differentiating hemorrhagic from non-hemorrhagic BAVMs. WSS did not demonstrate differences across any clinical groups. CONCLUSION: Flow quantification and angioarchitecture analysis of BAVMs showed similar efficacy as evaluated by associations with hemorrhagic presentation. High flow affects both arterial and venous angioarchitecture, reflecting the nature of low vascular resistance in BAVMs.

Clinical characteristics and long-term outcome of cerebral cavernous malformations-related epilepsy.

OBJECTIVE: Cerebral cavernous malformations (CCMs) present variably, and epileptic seizures are the most common symptom. The factors contributing to cavernoma-related epilepsy (CRE) and drug resistance remain inconclusive. The outcomes of CRE after different treatment modalities have not yet been fully addressed. This study aimed to characterize the clinical features of patients with CRE and the long-term seizure outcomes of medical and surgical treatment strategies. METHODS: This was a retrospective cohort of 135 patients with CCM who were diagnosed in 2007-2011 and followed up for 93.6 months on average. The patients were divided into drug-resistant epilepsy (DRE; n = 29), non-DRE (n = 45), and no epilepsy (NE; n = 61). RESULTS: Temporal CCM was the factor most strongly associated with the development of both CRE and DRE. The majority of patients with single temporal CCMs had CRE (86.8%, n = 33), and 50% had DRE, whereas only 14.7% (n = 5) with a nontemporal supratentorial CCM had DRE (p < .05). The most common lesion site in the DRE group was the mesiotemporal lobe (50%). Multiple CCMs were more frequently observed in the CRE (29.2%) than the NE (11.5%) group (p < .05). In patients with CRE, multiple lesions were associated with a higher rebleeding rate (odds ratio = 11.1), particularly in those with DRE (odds ratio = 15.4). The majority of patients who underwent resective surgery for DRE (76.5%, n = 13) achieved International League Against Epilepsy Class I and II seizure outcomes even after a long disease course. SIGNIFICANCE: Temporal CCM not only predisposes to CRE but also is a major risk factor for drug resistance. The mesiotemporal lobe is the most epileptogenic zone. Multiple CCMs are another risk factor for CRE and increase the rebleeding risk in these patients. Surgical resection could provide beneficial long-term seizure outcomes in patients with DRE.

EGFR mutant status and tyrosine-kinase inhibitors affect the GKRS outcomes for NSCLC brain metastases.

OBJECTIVE: Tyrosine kinase inhibitors (TKIs) is the first-line treatment for EGFR-positive non-small cell lung cancer (NSCLC); however, its applicability to patients with wild-type NSCLC remains an issue of contention. This study compared the effects of gamma knife radiosurgery (GKRS) alone versus combining GKRS and TKIs in treating two genetic forms of NSCLC. METHODS: This retrospective study examined 479 NSCLC patients with 1982 brain metastases who underwent GKRS and for whom imaging follow-up data or death records were available. All our patients were consecutive. All gene mutations were confirmed by lung biopsy. The three main endpoints in this study were overall survival (OS), local intracranial tumor control (LC), and distal intracranial tumor control (DC). RESULTS: There were 296 NSCLC patients with EGFR positive: TKI treatment (n = 262) and without TKI treatment (n = 34). GKRS + TKIs was more effective than GKRS alone in terms of OS (HR 0.53, p = 0.085) and DC (HR 0.51, p < 0.001). There were 150 NSCLC patients with wild-type EGFR: TKI treatment (n = 50) and without TKI treatment (n = 100). GKRS + TKIs was less effective than GKRS alone in terms of OS (HR 1.82, p = 0.049) and DC (HR: 1.40, p = 0.011). We observed no difference in terms of LC in both genetic groups. CONCLUSIONS: Combining GKRS with TKIs proved effective in EGFR positive NSCLC patients; however, we do not observe the similar results when combining GKRS with TKIs for patients with wild-type NSCLC.

Shortened cerebral circulation time correlates with seizures in brain arteriovenous malformation: a cross-sectional quantitative digital subtraction angiography study.

OBJECTIVE: Seizure is the most common clinical presentation in patients with nonhemorrhagic brain arteriovenous malformations (BAVMs) and it influences their quality of life. Angioarchitectural analysis of the seizure risk for BAVMs is subjective and does not consider hemodynamics. This study aimed to investigate the angioarchitectural and hemodynamic factors that may be associated with seizure in patients with BAVMs. METHODS: From 2011 to 2019, 104 patients with supratentorial BAVMs without previous hemorrhage or treatment were included and grouped according to the initial presentation of seizure. Their angiograms and MRI results were analyzed for morphological characteristics and quantitative digital subtraction angiography (QDSA) parameters. Modified cerebral circulation time (mCCT) was defined as the difference between the bolus arrival time of the ipsilateral cavernous internal carotid artery and the parietal vein on lateral DSA. Logistic regression analysis was performed to estimate the odds ratio (OR) for BAVMs presenting with seizure. RESULTS: The seizure group had shorter mCCT (1.98 s vs. 2.44 s, p = 0.005) and more BAVMs with temporal location (45% vs. 30.8%, p = 0.013), neoangiogenesis (55% vs. 33%, p = 0.03), and long draining veins (95% vs. 72%, p = 0.004) than did the nonseizure group. Shorter mCCT (OR: 3.4, p = 0.02), temporal location (OR: 13.4, p < 0.001), and neoangiogenesis (OR: 4.7, p = 0.013) were independently associated with higher risks of seizure, after adjustments for age, gender, BAVM volume, and long draining vein. CONCLUSIONS: Shorter mCCT, temporal location, and neoangiogenesis were associated with epileptic BAVMs. QDSA can objectively evaluate hemodynamic changes in epileptic BAVMs. KEY POINTS: • Quantitative digital subtraction angiography may be used to evaluate the hemodynamic differences between brain arteriovenous malformations presenting with and without seizure. • BAVMs with temporal location, neoangiogenesis, and shortened cerebral circulation time were more likely to present with seizure.

Cerebrospinal fluid diversion and outcomes for lung cancer patients with leptomeningeal carcinomatosis.

OBJECTIVE: To investigate the outcomes of cerebrospinal fluid (CSF) diversion in lung cancer patients with leptomeningeal carcinomatosis (LMC). METHODS: A retrospective review of consecutive lung cancer patients with LMC suffering from increased intracranial pressure (IICP) and hydrocephalus between February 2017 and February 2020. We evaluated the survival benefit of CSF diversion surgery and assessed the outcomes of treatments administered post-LMC in terms of overall survival and shunt-related complications. RESULTS: The study cohort included 50 patients (median age: 59 years). Ventricular peritoneal (VP) shunts were placed in 33 patients, and lumbar peritoneal (LP) shunts were placed in 7 patients. Programmable shunts were placed in 36 patients. Shunt adjustment was performed in 19 patients. Kaplan-Meier analysis revealed that shunt placement increased overall survival from 1.95 months to 6.21 months (p = 0.0012) and increased Karnofsky Performance Scores (KPS) from 60 to 70. Univariate analysis revealed no difference between VP or LP shunts in terms of survival. No differences in post-shunt systemic treatments (tyrosine kinase inhibitors (TKIs) or systemic treatments) were observed in overall survival. Shunt-related complications were noted in 7 patients, including shunt obstruction (n = 4), infection (n = 1), and over-drainage (n = 2). CONCLUSION: CSF diversion (VP or LP shunt) appears to be an effective and safe treatment for lung cancer patients with LMC and hydrocephalus. Programmable shunts should be considered for complex cases, which commonly require pressure adjustments as the disease progresses.

Sinovenous outflow in lateral sinus dural arteriovenous fistulas after stereotactic radiosurgery: a retrospective longitudinal imaging study.

PURPOSE: To investigate sinovenous outflow restriction (SOR) in lateral sinus dural arteriovenous fistulas (LSDAVFs) after Gamma Knife radiosurgery (GKRS) and its association with complete obliteration. METHODS: We retrospectively (1995-2019) enrolled 39 patients with LSDAVFs who had undergone GKRS alone and evaluated their angiography and magnetic resonance imaging (MRI) before and after GKRS. The LS conduits ipsilateral and contralateral to the DAVFs were scored using a 5-point scoring system, with scores ranging from 0 (total occlusion) to 4 (fully patent). SOR was defined by a conduit score < 2. Demographics, imaging features, and outcomes were compared between patients with and without ipsilateral SOR after GKRS. Logistic regression analysis was performed to estimate the odds ratio (OR) for obliteration with the imaging findings. RESULTS: After a median angiographic follow-up of 28 months for the 39 patients, the ipsilateral LS became more restrictive (median conduit score before and after GKRS: 2 vs. 1, p = .011). Twenty-one patients with ipsilateral SOR after GKRS had a significantly lower obliteration rate (52.4% vs. 94.4%, p = .005) than those without SOR. Follow-up SOR was independently associated with a lower obliteration rate (OR 0.05, p = .017) after adjustment for age, cortical venous reflux, and absent sinus flow void on MRI. CONCLUSION: This study demonstrates a restrictive change of outflow in LSDAVFs after GKRS and a lower obliteration rate in patients with SOR. Follow-up imaging for SOR may help predict outcomes of these patients.

Long-term cognitive and multimodal imaging outcomes after carotid artery stenting vs intensive medication alone for severe asymptomatic carotid stenosis.

BACKGROUND: Severe carotid stenosis is associated with cognitive impairment, which may be attributed to asymptomatic microembolism and/or chronic hypoperfusion. We aim to evaluate the long-term cognitive and brain connectivity outcomes of carotid artery stenting (CAS) for asymptomatic ≥70% stenosis of the extracranial internal carotid artery (ICA). METHODS: We conducted a non-randomized controlled study to compare intensive medical therapy alone (Med) or in combination with carotid artery stenting for the composite vascular events, neuropsychological, and multimodal magnetic resonance perfusion imaging and diffusion tensor imaging outcomes. RESULTS: Sixty-nine patients were followed for a mean of 2.3 years (31 Med, 38 CAS) and 11 patients had composite vascular events of all-cause death, ischemic stroke, or myocardial infarction (6 Med vs 5 CAS). Forty-six asymptomatic subjects completed neuropsychological and multimodality imaging follow-ups (23 Med, 23 CAS). Compared to the Med group, the CAS group had a modest improvement of 12-item delayed verbal memory (8.9 ± 2.4 to 9.8 ± 2.7 vs 9.0 ± 2.1 to 8.9 ± 2.3, p = 0.04), but not in global cognition, attention or executive function, which was associated with increased structural connectivity of fractional anisotropy at the ipsilateral deep white matter. Importantly, the memory improvement was correlated with the perfusion increment at the ipsilateral middle cerebral artery territory. CONCLUSION: For asymptomatic extracranial carotid steno-occlusion, successful carotid revascularization in addition to intensive medical treatment may potentially benefit cognitive reserve and connectivity strength which are partly attributed to restoration of non-critical hypoperfusion.

Application of Flat-Panel Volume Computed Tomography to Evaluate Cerebral Hemorrhage After Mechanical Thrombectomy of Acute Embolic Stroke of the Anterior Circulation.

OBJECTIVE: The aim of the study was to evaluate cerebral hemorrhage (CH) and contrast media leakage (CML or commonly synonymous with "contrast staining") differentiation on flat-panel volume computed tomography (FPVCT) after intra-arterial mechanical thrombectomy. METHODS: We evaluated patients with hyperattenuation on FPVCT after intra-arterial mechanical thrombectomy between 2018 and 2021 by multiple parameters on CT angiography, FPVCT, CT, and/or magnetic resonance imaging. RESULTS: The CH (n = 43) versus CML (n = 24) groups revealed: (1) regional anatomical characteristics (preserved and distorted): 7 of 43 (9.6%) and 36 of 43 (83.7%) versus 22 of 24 (91.7%) and 2 of 24 (8.3%, P < 0.001); (2) thrombus in proximal two-thirds versus distal one-thirds M1 segment of middle cerebral artery (preserved and distorted): 17 of 21 (81.0%) and 4 of 21 (19.0%) versus 5 of 11 (45.5%) and 6 of 11 (54.5%, P = 0.040); and (3) average density ratio: 1.83 ± 0.65 versus 1.35 ± 0.13 (P = 0.004). CONCLUSIONS: Contrast media leakage can be differentiated from CH by preserved regional anatomical characteristics and relatively low average density ratio on FPVCT. Patients with CML who have embolism in proximal two thirds of M1 segment are more likely to develop hyperattenuation with preserved regional anatomy.

Does the Diffuseness of the Nidus Affect the Outcome of Stereotactic Radiosurgery in Patients with Unruptured Cerebral Arteriovenous Malformations?

BACKGROUND: We proposed an algorithm to automate the components within the identification of components within the nidus of cerebral arteriovenous malformations (AVMs) which may be used to analyze the relationship between its diffuseness and treatment outcomes following stereotactic radiosurgery (SRS). OBJECTIVES: to determine the impact of the diffuseness of the AVM nidus on SRS outcomes. METHODS: This study conducted regular follow-ups of 209 patients with unruptured AVMs who underwent SRS. The diffuseness of the AVM nidus was estimated by quantifying the proportions of vascular nidal component, brain parenchyma, and cerebrospinal fluid in T2-weighted MRIs. We used Cox regression analysis to characterize the association between nidal diffuseness and treatment outcomes in terms of obliteration rate and radiation-induced change (RICs) rate following SRS. RESULTS: The median AVM volume was 20.7 cm3. The median duration of imaging follow-up was 51 months after SRS. The overall AVM obliteration rate was 68.4%. RICs were identified in 156 of the 209 patients (74.6%). The median proportions of the nidus of AVM and brain parenchyma components within the prescription isodose range were 30.2 and 52.2%, respectively. Cox regression multivariate analysis revealed that the only factor associated with AVM obliteration rate after SRS was AVM volume. However, a larger AVM volume (>20 mL) and a larger proportion of brain parenchyma (>50%) within the prescription isodose range were both correlated with a higher RIC rate following SRS. CONCLUSIONS: The diffuseness of the nidus indeed appears to affect the RIC rate following SRS in patients with unruptured AVMs.

Radiomics as prognostic factor in brain metastases treated with Gamma Knife radiosurgery.

PURPOSE: Gamma Knife radiosurgery (GKRS) is a non-invasive procedure for the treatment of brain metastases. This study sought to determine whether radiomic features of brain metastases derived from pre-GKRS magnetic resonance imaging (MRI) could be used in conjunction with clinical variables to predict the effectiveness of GKRS in achieving local tumor control. METHODS: We retrospectively analyzed 161 patients with non-small cell lung cancer (576 brain metastases) who underwent GKRS for brain metastases. The database included clinical data and pre-GKRS MRI. Brain metastases were demarcated by experienced neurosurgeons, and radiomic features of each brain metastasis were extracted. Consensus clustering was used for feature selection. Cox proportional hazards models and cause-specific proportional hazards models were used to correlate clinical variables and radiomic features with local control of brain metastases after GKRS. RESULTS: Multivariate Cox proportional hazards model revealed that higher zone percentage (hazard ratio, HR 0.712; P = .022) was independently associated with superior local tumor control. Similarly, multivariate cause-specific proportional hazards model revealed that higher zone percentage (HR 0.699; P = .014) was independently associated with superior local tumor control. CONCLUSIONS: The zone percentage of brain metastases, a radiomic feature derived from pre-GKRS contrast-enhanced T1-weighted MRIs, was found to be an independent prognostic factor of local tumor control following GKRS in patients with non-small cell lung cancer and brain metastases. Radiomic features indicate the biological basis and characteristics of tumors and could potentially be used as surrogate biomarkers for predicting tumor prognosis following GKRS.

Repeated gamma knife radiosurgery enables longer tumor control in cases of highly-recurrent intracranial ependymoma.

PURPOSE: Stereotactic radiosurgery (SRS) is a potential re-irradiation treatment for recurrent intracranial ependymoma after prior radiation therapy. The purpose of this study was to examine the efficacy and safety of repeated SRS in the treatment of recurrent intracranial ependymomas. METHODS: This is a retrospective study of consecutive patients with residual or recurrent intracranial ependymomas who were treated with SRS between 1993 and 2018. Tumor progression was defined as a ≥ 10% increase in tumor volume. Tumor regression was defined as a ≥ 10% reduction in tumor volume. A tumor that remained within 10% of its original volume was defined as stable. Tumor control comprised tumor regression and stability. Time-dependent analyses were performed using two treatment failure endpoint definitions: (1) evidence of local tumor progression or distant metastasis (single SRS analysis), and (2) lack of tumor response to SRS (repeated SRS analysis). These analyses were adjusted for the competing risk of death. RESULTS: The study comprised 37 patients (65 intracranial ependymomas) who underwent multiple SRS sessions (range: 1-7). Median age was 10.2 years (range: 0.8-53.8 years), and median tumor volume was 1.5 mL (range: 0.01-22.5 mL). The median radiation dose was 13.3 Gy (range: 7.9-22.0 Gy) at a median isodose line of 57% (range: 50-90%). Overall tumor control rates in the single SRS analysis adjusting for the competing risk of death were 53.6%, 30.5%, and 23.6% at 1, 3, and 5 years, respectively. Overall tumor control rates in the repeated SRS analysis adjusting for the competing risk of death were 70.6%, 50.4%, and 43.1% at 1, 3, and 5 years, respectively. Prior gross total resection was the only independent predictor of overall tumor control after SRS (aHR = 25.62 (1.55-422.1), p = 0.02). CONCLUSIONS: Repeated GKRS appeared to be an effective treatment strategy for recurrent or residual intracranial ependymomas, with acceptable complication rates.