Comparative analysis of the spatial distribution of brain metastases across several primary cancers using machine learning and deep learning models.

OBJECTIVE: Brain metastases (BM) are associated with poor prognosis and increased mortality rates, making them a significant clinical challenge. Studying BMs can aid in improving early detection and monitoring. Systematic comparisons of anatomical distributions of BM from different primary cancers, however, remain largely unavailable. METHODS: To test the hypothesis that anatomical BM distributions differ based on primary cancer type, we analyze the spatial coordinates of BMs for five different primary cancer types along principal component (PC) axes. The dataset includes 3949 intracranial metastases, labeled by primary cancer types and with six features. We employ PC coordinates to highlight the distinctions between various cancer types. We utilized different Machine Learning (ML) algorithms (RF, SVM, TabNet DL) models to establish the relationship between primary cancer diagnosis, spatial coordinates of BMs, age, and target volume. RESULTS: Our findings revealed that PC1 aligns most with the Y axis, followed by the Z axis, and has minimal correlation with the X axis. Based on PC1 versus PC2 plots, we identified notable differences in anatomical spreading patterns between Breast and Lung cancer, as well as Breast and Renal cancer. In contrast, Renal and Lung cancer, as well as Lung and Melanoma, showed similar patterns. Our ML and DL results demonstrated high accuracy in distinguishing BM distribution for different primary cancers, with the SVM algorithm achieving 97% accuracy using a polynomial kernel and TabNet achieving 96%. The RF algorithm ranked PC1 as the most important discriminating feature. CONCLUSIONS: In summary, our results support accurate multiclass ML classification regarding brain metastases distribution.

The Intersectionality of Food Insecurity, Job Insecurity, Healthcare Insecurity, and Mental Health Challenges in NYC Households During Covid-19.

Our intersectional research explored food insecurity and job insecurity as predictors of healthcare insecurity and mental health challenges among households living in economic instability since the COVID19 pandemic began. The New York City COVID19 Research Team adapted a validated, web based, anonymous survey questionnaire using a Social Determinants of Health Framework. The study oversampled underserved populations with a total of 2,099 participants. We report strong associations between food insecurity and job insecurity among healthcare insecure households, and significant mental health challenges among food insecure and healthcare insecure households. This underscores the need for integrated social policies to protect underserved urban populations.

Outcome Evaluation of Repeat Stereotactic Radiosurgery for Cerebral Arteriovenous Malformations.

BACKGROUND: Repeat stereotactic radiosurgery (SRS) for persistent cerebral arteriovenous malformation (AVM) has generally favorable patient outcomes. However, reporting studies are limited by small patient numbers and single-institution biases. The purpose of this study was to provide the combined experience of multiple centers, in an effort to fully define the role of repeat SRS for patients with arteriovenous malformation. METHODS: This multicenter, retrospective cohort study included patients treated with repeat, single-fraction SRS between 1987 and 2022. Follow-up began at repeat SRS. The primary outcome was a favorable patient outcome, defined as a composite of nidus obliteration in the absence of hemorrhage or radiation-induced neurological deterioration. Secondary outcomes were obliteration, hemorrhage risk, and symptomatic radiation-induced changes. Competing risk analysis was performed to compute yearly rates and identify predictors for each outcome. RESULTS: The cohort comprised 505 patients (254 [50.3%] males; median [interquartile range] age, 34 [15] years) from 14 centers. The median clinical and magnetic resonance imaging follow-up was 52 (interquartile range, 61) and 47 (interquartile range, 52) months, respectively. At last follow-up, favorable outcome was achieved by 268 (53.1%) patients (5-year probability, 50% [95% CI, 45%-55%]) and obliteration by 300 (59.4%) patients (5-year probability, 56% [95% CI, 51%-61%]). Twenty-eight patients (5.6%) experienced post-SRS hemorrhage with an annual incidence rate of 1.38 per 100 patient-years. Symptomatic radiation-induced changes were evident in 28 (5.6%) patients, with most occurring in the first 3 years. Larger nidus volumes (between 2 and 4 cm3, subdistribution hazard, 0.61 [95% CI, 0.44-0.86]; P=0.005; >4 cm3, subdistribution hazard, 0.47 [95% CI, 0.32-0.7]; P<0.001) and brainstem/basal ganglia involvement (subdistribution hazard, 0.6 [95% CI, 0.45-0.81]; P<0.001) were associated with reduced probability of favorable outcome. CONCLUSIONS: Repeat SRS confers reasonable obliteration rates with a low complication risk. With most complications occurring in the first 3 years, extending the latency period to 5 years generally increases the rate of favorable patient outcomes and reduces the necessity of a third intervention.

Immune checkpoint inhibition and single fraction stereotactic radiosurgery in brain metastases from non-small cell lung cancer: an international multicenter study of 395 patients.

PURPOSE: Approximately 80% of brain metastases originate from non-small cell lung cancer (NSCLC). Immune checkpoint inhibitors (ICI) and stereotactic radiosurgery (SRS) are frequently utilized in this setting. However, concerns remain regarding the risk of radiation necrosis (RN) when SRS and ICI are administered concurrently. METHODS: A retrospective study was conducted through the International Radiosurgery Research Foundation. Logistic regression models and competing risks analyses were utilized to identify predictors of any grade RN and symptomatic RN (SRN). RESULTS: The study included 395 patients with 2,540 brain metastases treated with single fraction SRS and ICI across 11 institutions in four countries with a median follow-up of 14.2 months. The median age was 67 years. The median margin SRS dose was 19 Gy; 36.5% of patients had a V12 Gy ≥ 10 cm3. On multivariable analysis, V12 Gy ≥ 10 cm3 was a significant predictor of developing any grade RN (OR: 2.18) and SRN (OR: 3.95). At 1-year, the cumulative incidence of any grade and SRN for all patients was 4.8% and 3.8%, respectively. For concurrent and non-concurrent groups, the cumulative incidence of any grade RN was 3.8% versus 5.3%, respectively (p = 0.35); and for SRN was 3.8% vs. 3.6%, respectively (p = 0.95). CONCLUSION: The risk of any grade RN and symptomatic RN following single fraction SRS and ICI for NSCLC brain metastases increases as V12 Gy exceeds 10 cm3. Concurrent ICI and SRS do not appear to increase this risk. Radiosurgical planning techniques should aim to minimize V12 Gy.

Stereotactic radiosurgery for Koos grade IV vestibular schwannoma in patients ≥ 65 years old: a multi-institutional retrospective study.

BACKGROUND: Surgery is the preferred treatment for large vestibular schwannomas (VS). Good tumor control and cranial nerve outcomes were described in selected Koos IV VS after single-session stereotactic radiosurgery (SRS), but outcomes in elderly patients have never been specifically studied. The aim of this study is to report clinical and radiological outcomes after single-session SRS for Koos IV VS in patients ≥ 65 years old. METHOD: This multicenter, retrospective study included patients ≥ 65 years old, treated with primary, single-session SRS for a Koos IV VS, and at least 12 months of follow-up. Patients with life-threatening or incapacitating symptoms were excluded. Tumor control rate, hearing, trigeminal, and facial nerve function were studied at last follow-up. RESULTS: One-hundred and fifty patients (median age of 71.0 (IQR 9.0) years old with a median tumor volume of 8.3 cc (IQR 4.4)) were included. The median prescription dose was 12.0 Gy (IQR 1.4). The local tumor control rate was 96.0% and 86.2% at 5 and 10 years, respectively. Early tumor expansion occurred in 6.7% and was symptomatic in 40% of cases. A serviceable hearing was present in 16.1% prior to SRS and in 7.4% at a last follow-up of 46.5 months (IQR 55.8). The actuarial serviceable hearing preservation rate was 69.3% and 50.9% at 5 and 10 years, respectively. Facial nerve function preservation or improvement rates at 5 and 10 years were 98.7% and 91.0%, respectively. At last follow-up, the trigeminal nerve function was improved in 14.0%, stable in 80.7%, and worsened in 5.3% of the patients. ARE were noted in 12.7%. New hydrocephalus was seen in 8.0% of patients. CONCLUSION: SRS can be a safe alternative to surgery for selected Koos IV VS in patients ≥ 65 years old. Further follow-up is warranted.

Radiation necrosis in renal cell carcinoma brain metastases treated with checkpoint inhibitors and radiosurgery: An international multicenter study.

BACKGROUND: Patients with renal cell carcinoma (RCC) brain metastases are frequently treated with immune checkpoint inhibitors (ICIs) and stereotactic radiosurgery (SRS). However, data reporting on the risk of developing radiation necrosis (RN) are limited. METHODS: RN rates were compared for concurrent therapy (ICI/SRS administration within 4 weeks of one another) and nonconcurrent therapy with the χ2 test. Univariable logistic regression was used to identify factors associated with developing RN. RESULTS: Fifty patients (23 concurrent and 27 nonconcurrent) with 395 brain metastases were analyzed. The median follow-up was 12.1 months; the median age was 65 years. The median margin dose was 20 Gy, and 4% underwent prior whole-brain radiation therapy (WBRT). The median treated tumor volume was 3.32 cm3 (range, 0.06-42.38 cm3 ); the median volume of normal brain tissue receiving a dose of 12 Gy or higher (V12 Gy) was 8.42 cm3 (range, 0.27-111.22 cm3 ). Any-grade RN occurred in 17.4% and 22.2% in the concurrent and nonconcurrent groups, respectively (P = .67). Symptomatic RN occurred in 4.3% and 14.8% in the concurrent and nonconcurrent groups, respectively (P = .23). Increased tumor volume during SRS (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.01-1.19; P = .04) was associated with developing RN, although V12 Gy (OR, 1.03; 95% CI, 0.99-1.06; P = .06), concurrent therapy (OR, 0.74; 95% CI, 0.17-2.30; P = .76), prior WBRT, and ICI agents were not statistically significant. CONCLUSIONS: Symptomatic RN occurs in a minority of patients with RCC brain metastases treated with ICI/SRS. The majority of events were grade 1 to 3 and were managed medically. Concurrent ICI/SRS does not appear to increase this risk. Attempts to improve dose conformality (reduce V12) may be the most successful mitigation strategy in single-fraction SRS.

Stereotactic radiosurgery versus active surveillance for asymptomatic, skull-based meningiomas: an international, multicenter matched cohort study.

OBJECTIVE: The optimal management of asymptomatic, skull-based meningiomas is not well defined. The aim of this study is to compare the imaging and clinical outcomes of patients with asymptomatic, skull-based meningiomas managed either with upfront stereotactic radiosurgery (SRS) or active surveillance. METHODS: This retrospective, multicenter study involved patients with asymptomatic, skull-based meningiomas. The study end-points included local tumor control and the development of new neurological deficits attributable to the tumor. Factors associated with tumor progression and neurological morbidity were also analyzed. RESULTS: The combined unmatched cohort included 417 patients. Following propensity score matching for age, tumor volume, and follow-up 110 patients remained in each cohort. Tumor control was achieved in 98.2% and 61.8% of the SRS and active surveillance cohorts, respectively. SRS was associated with superior local tumor control (p < 0.001, HR = 0.01, 95% CI = 0.002-0.13) compared to active surveillance. Three patients (2.7%) in the SRS cohort and six (5.5%) in the active surveillance cohort exhibited neurological deterioration. One (0.9%) patient in the SRS-treated and 11 (10%) patients in the active surveillance cohort required surgical management of their meningioma during follow-up. CONCLUSIONS: SRS is associated with superior local control of asymptomatic, skull-based meningiomas as compared to active surveillance and does so with low morbidity rates. SRS should be offered as an alternative to active surveillance as the initial management of asymptomatic skull base meningiomas. Active surveillance policies do not currently specify the optimal time to intervention when meningioma growth is noted. Our results indicate that if active surveillance is the initial management of choice, SRS should be recommended when radiologic tumor progression is noted and prior to clinical progression.

Stereotactic radiosurgery versus active surveillance for incidental, convexity meningiomas: a matched cohort analysis from the IMPASSE study.

BACKGROUND: The optimal treatment strategy of asymptomatic, convexity meningiomas, remains unclear. OBJECTIVE: The purpose of this study was to define the safety and efficacy of stereotactic radiosurgery (SRS) in the management of patients with asymptomatic convexity meningiomas. METHODS: Data of SRS-treated patients from 14 participating centers and patients managed conservatively for an asymptomatic, convexity-located meningioma were compared. Local tumor control rate and development of new neurologic deficits were evaluated in the active surveillance and in the SRS-treated cohorts. RESULTS: In the unmatched cohorts, there were 99 SRS-treated patients and 140 patients managed conservatively for an asymptomatic, convexity meningioma. Following propensity score matching for age, there were 98 patients in each cohort. In the matched cohorts, tumor control was achieved in 99% of SRS-treated, and in 69.4% of conservatively managed patients (p < 0.001). New neurological deficits occurred in 2.0% of patients in each of the matched cohorts (p = 1.00). Increasing age was predictive of tumor growth [(OR 1.1; 95% CI (1.04 - 1.2), (p < 0.001)]. CONCLUSION: This is one of the first reports to suggest that SRS is a low risk and effective treatment strategy for asymptomatic incidentally discovered convexity meningiomas. In this study, tumor control was achieved in significantly more patients after radiosurgery compared to those managed with active surveillance. SRS may be offered at diagnosis of an asymptomatic convexity meningioma and should be recommended when meningioma growth is noted on follow-up.

Stereotactic radiosurgery for Koos grade IV vestibular schwannoma in young patients: a multi-institutional study.

PURPOSE: Surgery is the treatment of choice for large vestibular schwannomas (VS). Stereotactic radiosurgery (SRS) has been suggested as an alternative to resection in selected patients. However, the safety and efficacy of SRS in Koos grade IV patients ≤ 45 years old has not been evaluated. The aim of this study is to describe the clinical and radiological outcomes of Koos grade IV in young patient managed with a single-session SRS. METHODS: This retrospective, multicenter analysis included SRS-treated patients, ≤ 45 years old presenting with non-life threatening or incapacitating symptoms due to a Koos Grade IV VS and with follow-up ≥ 12 months. Tumor control and neurological outcomes were evaluated. RESULTS: 176 patients [median age of 36.0 (IQR 9) and median tumor volume of 9.3 cm3 (IQR 4.7)] were included. The median prescription dose was 12 Gy (IQR 0.5). Median follow-up period was 37.5 (IQR 53.5) months. The 5- and 10-year progression-free survival was 90.9% and 86.7%. Early tumor enlargement occurred in 10.9% of cases and was associated with tumor progression at the last follow-up. The probability of serviceable hearing preservation at 5- and 10-years was 56.8% and 45.2%, respectively. The probability of improvement or preservation of facial nerve function was 95.7% at 5 and 10-years. Adverse radiation effects were noted in 19.9%. New-onset hydrocephalus occurred in 4.0%. CONCLUSION: Single-session SRS is a safe and effective alternative to surgical resection in selected patients ≤ 45 years old particularly those with medical co-morbidities and those who decline resection. Longer term follow up is warranted.

Stereotactic radiosurgery for asymptomatic petroclival region meningiomas: a focused analysis from the IMPASSE study.

BACKGROUND: The optimal management of asymptomatic, petroclival meningiomas remains incompletely defined. The purpose of this study was to evaluate the safety and efficacy of upfront stereotactic radiosurgery (SRS) for patients with asymptomatic, petroclival region meningiomas. METHODS: This retrospective, international, multicenter study involved patients treated with SRS for an asymptomatic, petroclival region meningioma. Study endpoints included local tumor control rate, procedural complications, and the emergence of new neurological deficits. RESULTS: There were 72 patients (22 males, mean age 59.53 years (SD ± 11.9)) with an asymptomatic meningioma located in the petroclival region who were treated with upfront SRS. Mean margin dose and maximum dose were 13.26 (SD ± 2.72) Gy and 26.14 (SD ± 6.75) Gy respectively. Median radiological and clinical follow-up periods post-SRS were 52.5 (IQR 61.75) and 47.5 months (IQR 69.75) respectively. At last follow-up, tumor control was achieved in all patients. SRS-related complications occurred in 6 (8.33%) patients, with 3 of them (4.17%) exhibiting new neurological deficits. CONCLUSIONS: Upfront SRS for asymptomatic, petroclival region meningiomas affords excellent local tumor control and does so with a relatively low risk of SRS-related complications. SRS can be considered at diagnosis of an asymptomatic petroclival region meningioma. If active surveillance is initially chosen, SRS should be recommended when growth is noted during radiological follow-up.

Robust arterial input function surrogate measurement from the superior sagittal sinus complex signal for fast dynamic contrast-enhanced MRI in the brain.

PURPOSE: Accurately estimating the arterial input function for dynamic contrast-enhanced MRI is challenging. An arterial input function is typically determined from signal magnitude changes related to a contrast agent, often leading to underestimation of peak concentrations. Alternatively, signal phase recovers the accurate peak concentration for straight vessels but suffers from high noise. A recent method proposed to fit the signal in the complex plane by combining the advantages of the previous 2 methods. The purpose of this work is to refine this complex-based method to determine the venous output function (VOF), an arterial input function surrogate, from the superior sagittal sinus. METHODS: We propose a state-of-the-art complex-based method that includes direct compensation for blood inflow and signal phase correction accounting for the curvature of the superior sagittal sinus, generally assumed collinear with B0 . We compared the magnitude-, phase-, and complex-based VOF determination methods against various simulated biases as well as for 29 brain metastases patients. RESULTS: Angulation of the superior sagittal sinus relative to B0 varied widely within patients, and its effect on the signal phase caused an underestimation of peak concentrations of up to 65%. Correction significantly increased the VOF peak concentration for the phase- and complex-based VOFs in the cohort. The phase-based method recovered accurate peak concentrations but lacked precision in the tail of the VOF. Our complex-based VOF completely recovered the effect of inflow and resulted in a high-peak concentration with limited noise. CONCLUSION: The new complex-based method resulted in high-quality VOF robust against superior sagittal sinus curvature and variations in patient positioning.

Stereotactic radiosurgery for IDH wild type glioblastoma: an international, multicenter study.

OBJECTIVE: Isocitrate dehydrogenase (IDH) mutation status is recommended used for diagnosis and prognostication of glioblastoma patients. We studied efficacy and safety of stereotactic radiosurgery (SRS) for patients with recurrent IDH-wt glioblastoma. METHODS: Consecutive patients treated with SRS for IDH-wt glioblastoma were pooled for this retrospective observational international multi-institutional study from institutions participating in the International Radiosurgery Research Foundation. RESULTS: Sixty patients (median age 61 years) underwent SRS (median dose 15 Gy and median treatment volume: 7.01 cm3) for IDH-wt glioblastoma. All patients had histories of surgery and chemotherapy with temozolomide, and 98% underwent fractionated radiation therapy. MGMT status was available for 42 patients, of which half of patients had MGMT mutant glioblastomas. During median post-SRS imaging follow-up of 6 months, 52% of patients experienced tumor progression. Median post-SRS progression free survival was 4 months. SRS prescription dose of > 14 Gy predicted longer progression free survival [HR 0.357 95% (0.164-0.777) p = 0.009]. Fifty-percent of patients died during post-SRS clinical follow-up that ranged from 1 to 33 months. SRS treatment volume of > 5 cc emerged as an independent predictor of shorter post-SRS overall survival [HR 2.802 95% CI (1.219-6.444) p = 0.02]. Adverse radiation events (ARE) suggestive of radiation necrosis were diagnosed in 6/55 (10%) patients and were managed conservatively in the majority of patients. CONCLUSIONS: SRS prescription dose of > 14 Gy is associated with longer progression free survival while tumor volume of > 5 cc is associated with shorter overall survival after SRS for IDH-wt glioblastomas. AREs are rare and are typically managed conservatively.

Stereotactic radiosurgery for clinoid meningiomas: a multi-institutional study.

PURPOSE: Resection of clinoid meningiomas can be associated with significant morbidity. Experience with stereotactic radiosurgery (SRS) for clinoid meningiomas remains limited. We studied the safety and effectiveness of SRS for clinoid meningiomas. METHODS: From twelve institutions participating in the International Radiosurgery Research Foundation, we pooled patients treated with SRS for radiologically suspected or histologically confirmed WHO grade I clinoid meningiomas. RESULTS: Two hundred seven patients (median age: 56 years) underwent SRS for clinoid meningiomas. Median treatment volume was 8.02 cm3, and 87% of tumors were immediately adjacent to the optic apparatus. The median tumor prescription dose was 12 Gy, and the median maximal dose to the anterior optic apparatus was 8.5 Gy. During a median post-SRS imaging follow-up of 51.1 months, 7% of patients experienced tumor progression. Greater margin SRS dose (HR = 0.700, p = 0.007) and pre-SRS radiotherapy (HR = 0.004, p < 0.001) were independent predictors of better tumor control. During median visual follow-up of 48 months, visual function declined in 8% of patients. Pre-SRS visual deficit (HR = 2.938, p = 0.048) and maximal radiation dose to the optic apparatus of ≥ 10 Gy (HR = 11.297, p = 0.02) independently predicted greater risk of post-SRS visual decline. Four patients experienced new post-SRS cranial nerve V neuropathy. CONCLUSIONS: SRS allows durable control of clinoid meningiomas and visual preservation in the majority of patients. Greater radiosurgical prescription dose is associated with better tumor control. Radiation dose to the optic apparatus of ≥ 10 Gy and visual impairment before the SRS increase risk of visual deterioration.

Perturbing the activity of the superior temporal gyrus during pain encoding prevents the exaggeration of pain memories: A virtual lesion study using single-pulse transcranial magnetic stimulation.

BACKGROUND: Past studies have shown that pain memories are often inaccurate, a phenomenon known as mnemonic pain bias. Pain memories are thought to play an important role on how future pain is felt. Recent evidence from our laboratory suggests that individuals who exaggerate past pain display increased superior temporal gyrus (STG) activity during the encoding of experimental painful stimulations, suggesting that this brain structure plays an important role in pain memories. OBJECTIVE: /hypothesis. To determine whether a virtual lesion paradigm, targeting the STG during pain encoding, can affect long-lasting pain memories. We hypothesized that interfering with the activity of the STG would attenuate mnemonic bias. METHODS: Randomized double-blind study with two parallel groups. Participants received either sham (n = 21) or real (n = 21) transcranial magnetic stimulation (TMS - virtual lesion paradigm) over the STG during pain encoding (milliseconds after the administration of a painful stimuli). Pain intensity and unpleasantness were evaluated using a visual analog scale (VAS; 0 to 10) immediately after the painful event, and at recall, 2 months later. The mnemonic pain bias (calculated by subtracting the pain scores obtained at recall from the pain score obtained during encoding) was compared between the two groups for both pain intensity and unpleasantness. RESULTS: Participants in both groups did not differ in terms of age and gender (real TMS = 27 years ±â€¯9, 43% female; sham TMS = 25 years ±â€¯4, 49% female; p > 0.64). The mnemonic bias related to pain intensity was similar in both groups (p = 0.83). However, the mnemonic bias related to pain unpleasantness was lower in the real TMS group (p = 0.04). CONCLUSIONS: Our results provide the first evidence that the STG, is causally involved in the formation of biased memories of pain unpleasantness.

Risk of Brain Arteriovenous Malformation Hemorrhage Before and After Stereotactic Radiosurgery.

Background and Purpose- Understanding the hemorrhage risks associated with brain arteriovenous malformations (AVMs) before and after stereotactic radiosurgery (SRS) is important. The aims of this multicenter, retrospective cohort study are to evaluate and compare the rates of pre- and post-SRS AVM hemorrhage and identify risk factors. Methods- We pooled AVM SRS data from 8 institutions participating in the International Radiosurgery Research Foundation. Predictors of post-SRS hemorrhage were determined using a multivariate logistic regression model. Pre- and post-SRS hemorrhage rates were compared using Fisher exact test. Ruptured and unruptured AVMs were matched in a 1:1 ratio using propensity scores, and their outcomes were compared. Results- The study cohort comprised 2320 AVM patients who underwent SRS. Deep AVM location (odds ratio, 1.86; 95% CI, 1.19-2.92; P=0.007), the presence of an AVM-associated arterial aneurysm (odds ratio, 2.44; 95% CI, 1.63-3.66; P<0.001), and lower SRS margin dose (odds ratio, 0.93; 95% CI, 0.88-0.98; P=0.005) were independent predictors of post-SRS hemorrhage. The post-SRS hemorrhage rate was lower for obliterated versus patent AVMs (6.0 versus 22.3 hemorrhages/1000 person-years; P<0.001). The AVM hemorrhage rate decreased from 15.4 hemorrhages/1000 person-years before SRS to 11.9 after SRS ( P=0.001). The outcomes of the matched ruptured versus unruptured AVM cohorts were similar. Conclusions- SRS appears to reduce the risk of AVM hemorrhage, although this effect is predominantly driven by obliteration. Deep-seated AVMs are more likely to rupture during the latency period after SRS. AVM-associated aneurysms should be considered for selective occlusion before SRS of the nidus to ameliorate the post-SRS hemorrhage rate of these lesions.

Stereotactic Radiosurgery for Unruptured Versus Ruptured Pediatric Brain Arteriovenous Malformations.

Background and Purpose- The effects of prior hemorrhage on stereotactic radiosurgery (SRS) outcomes for pediatric arteriovenous malformations (AVMs) are not well defined. The aim of this multicenter, retrospective cohort study is to compare the SRS outcomes for unruptured versus ruptured pediatric AVMs. Methods- The International Radiosurgery Research Foundation pediatric AVM database from 1987 to 2018 was reviewed retrospectively. Favorable outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes. Associations between prior hemorrhage and outcomes were adjusted for baseline differences, inverse probability weights, and competing risks. Results- The study cohort comprised 153 unruptured and 386 ruptured AVMs. Favorable outcome was achieved in 48.4% and 60.4% of unruptured and ruptured AVMs, respectively (adjusted odds ratio, 1.353; P=0.190). Cumulative AVM obliteration probabilities were 51.2%, 59.4%, 64.2%, and 70.0% for unruptured and 61.0%, 69.3%, 74.0%, and 79.3% for ruptured AVMs at 4, 6, 8, and 10 years, respectively (subhazard ratio, 1.311; P=0.020). Cumulative post-SRS hemorrhage probabilities were 4.5%, 5.6%, 5.6%, and 9.8% for unruptured and 4.7%, 6.1%, 6.1%, and 10.6% for ruptured AVMs at 4, 6, 8, and 10 years, respectively (subhazard ratio, 1.086; P=0.825). Probabilities of AVM obliteration (adjusted subhazard ratio, 0.968; P=0.850) and post-SRS hemorrhage (adjusted subhazard ratio, 1.663; P=0.251) were comparable between the 2 cohorts after inverse probability weight adjustments. Symptomatic (15.8% versus 8.1%; adjusted odds ratio, 0.400; P=0.008) and permanent (9.2% versus 5.0%; adjusted odds ratio, 0.441; P=0.045) radiation-induced change were more common in unruptured AVMs. Conclusions- The overall outcomes after SRS for unruptured versus ruptured pediatric AVMs are comparable. However, symptomatic and permanent radiation-induced change occur more frequently in pediatric patients with unruptured AVMs.

Increased precision in the intravascular arterial input function with flow compensation.

PURPOSE: In this study, we investigate the effects of pulsatile flow and inflow on dynamic susceptibility-contrast MRI intravascular arterial input function measurement in human brain arteries and measure how they are affected by first-order flow compensation. METHODS: A dual-echo single-shot EPI sequence with alternating flow compensation gradients was used to acquire dynamic susceptibility-contrast images with electrocardiogram monitoring. The dynamic signal variations measured inside the middle cerebral and internal carotid arteries were associated to the pulsatile arterial blood velocities measured with a single-slice quantitative flow sequence throughout the cardiac cycle. RESULTS: Major inverse correlations between intravascular signal and blood velocity were found for the standard single-shot EPI sequence. Flow compensation reduces these correlated variations that contribute to signal physiological noise. This causes a significant twofold increase of intravascular SNR in the middle cerebral and the internal carotid arteries (2.3 ± 0.9, P = 0.03) and (2.0 ± 0.9, P = 0.04), respectively; and reduced phase SD for the internal carotid arteries (0.72 ± 0.14, P = 0.004). The correction proposed in this work translates into a quantitative arterial input function with reduced noise in the internal carotid arteries. CONCLUSION: The physiological noise added by pulsatile flow and inflow for intravascular arterial input function measurement in the brain arteries is significantly reduced by flow compensation.

Repeat stereotactic radiosurgery for the management of locally recurrent brain metastases.

PURPOSE: Stereotactic radiosurgery (SRS) is a well-established treatment option for brain metastases (BM). Repeat SRS for progressive BM is an increasingly used paradigm, although little data is available to support this practice. The goal of this study was to assess the safety and efficacy of a second SRS procedure on a previously treated BM. METHODS: We performed a retrospective metastasis-level analysis of patients who underwent two SRS procedures on the same lesion and for whom at least 6 months of radiological follow-up was available. The data collected included patient characteristics, clinical symptoms at time of treatment, SRS parameters, radiological response per RANO-BM criteria, clinical evolution and survival. RESULTS: Seventy-five BM in 56 patients were included in the analysis. Most frequent primary histologies were non-small-cell lung cancer (59%) and breast cancer (19%). At the second SRS, median treatment volume was 1.19 cc (range 0.07-20.6) treated with a median margin dose of 18 Gy (range 12-20) at the 50% isodose line (range 30-80%). Median follow-up was 11 months. Progression per RANO-BM criteria occurred in 31%, yielding actuarial local control at 1, 2, and 5 years of 68%, 54% and 54% respectively. At last follow-up, 10 patients (18%) had improved relative to the initial presentation, while 21 (38%) were stable and 25 (44%) were deteriorated. Radiation-induced edema and radionecrosis occurred in 8.3% and 5% respectively. The median survival from the diagnosis of BM was 30 months. CONCLUSION: Repeat SRS is a safe and effective novel therapeutic approach to consider in carefully selected patients.

Safety and efficacy of repeat radiosurgery for acromegaly: an International Multi-Institutional Study.

PURPOSE: Surgical resection is the first line treatment for growth hormone (GH) secreting tumors. Stereotactic radiosurgery (SRS) is recommended for patients who do not achieve endocrine remission after resection. The purpose of this study was to evaluate safety and efficacy of repeat radiosurgery for acromegaly. METHODS: Three hundred and ninety-eight patients with acromegaly treated with the Gamma Knife radiosurgery (Elekta AB, Stockholm) were identified from the International Gamma Knife Research Foundation database. Among these, 21 patients underwent repeated SRS with sufficient endocrine follow-up and 18 patients had sufficient imaging follow-up. Tumor control was defined as lack of adenoma progression on imaging. Endocrine remission was defined as a normal IGF-1 concentration while off medical therapy. RESULTS: Median time from initial SRS to repeat SRS was 5.0 years. The median imaging and endocrine follow-up duration after repeat SRS was 3.4 and 3.8 years, respectively. The median initial marginal dose was 17 Gy, and the median repeat marginal dose was 23 Gy. Of the 18 patients with adequate imaging follow up, 15 (83.3%) patients had tumor control and of 21 patients with endocrine follow-up, 9 (42.9%) patients had endocrine remission at last follow-up visit. Four patients (19.0%) developed new deficits after repeat radiosurgery. Of these, 3 patients had neurologic deficits and 1 patient had endocrine deficit. CONCLUSIONS: Repeat radiosurgery for persistent acromegaly offers a reasonable benefit to risk profile for this challenging patient cohort. Further studies are needed to identify patients best suited for this type of approach.

Psychiatric Neurosurgery: A Survey on the Perceptions of Psychiatrists and Residents.

OBJECTIVES: To evaluate the attitudes and perceptions of psychiatrists and psychiatry residents regarding neurosurgical procedures for treating psychiatric disorders and to identify potential barriers to patient referral. METHODS: A survey consisting of 25 questions was created using SurveyMonkey and was distributed to psychiatrists and psychiatry residents in Quebec. The study was approved by the McGill University Health Center's Research Ethics Board. Descriptive statistics and Friedman's test were performed using SPSS software. RESULTS: A total of 99 participants, including 64 residents and 35 psychiatrists, completed more than 75% of the survey and were included in data analysis. Overall, participants were significantly (p < 0.0005) more comfortable in referring patients suffering from treatment-resistant obsessive-compulsive disorder than from treatment-resistant major depressive disorder and preferred to refer patients for deep brain stimulation (DBS) rather than for anterior cingulotomy/capsulotomy (AC). Only 11.43% of psychiatrists had ever referred a patient for AC or DBS, and 34.69% of respondents felt that these procedures were dangerous. Lack of knowledge (82.83%) was viewed as the principal limiting factor, and 57.58% of respondents identified ≥6 different barriers to patient referral. The majority of participants (69.39%) were interested in improving their knowledge on psychiatric neurosurgery, and 82.65% felt that this subject should be included in the psychiatry residency curriculum. CONCLUSION: Overall, participants acknowledged having many limitations to referring patients for neurosurgical interventions. While informative conferences discussing neuromodulation/neuroablation could easily address many barriers, further studies are required to assess how these could change attitudes and patterns of referral.