Background: The hypoperfusion intensity ratio (HIR) has emerged as a vital measure of tissue-level collateral blood flow, helping to identify patients who are likely to benefit from mechanical thrombectomy (MT). We aimed to assess the HIR’s predictive accuracy for clinical outcomes following MT in patients with acute ischemic stroke. Methods: PubMed, Embase, and Scopus were searched to identify studies comparing good versus poor HIR groups based on studies’ reported cut-offs. We pooled binary outcomes to calculate odds ratios (OR) and continuous outcomes to calculate mean differences (MD) with 95% confidence intervals (95% CI) using random-effects models. PROSPERO registration code: CRD42024609185. Results: 14 studies with 2987 patients, 1553 with good HIR and 1434 with poor HIR, were included in this meta-analysis. Patients with poor HIR exhibited a significantly higher baseline infarct volume compared with those with good HIR (MD 30.6 mL, 95% CI 20.8 mL to 40.3 mL, P<0.01), though baseline National Institutes of Health Stroke Scale (NIHSS) (P=0.12) and Alberta Stroke Program Early CT Score (ASPECTS) (P=0.35) were comparable between groups. The rates of infarct growth (MD 22.4 mL, 95% CI 6.7 mL to 38.0 mL, P<0.01) and 3-month mortality (OR 2.18, 95% CI 1.04 to 4.58, P=0.04) were higher among the poor HIR group and good functional recovery (modified Rankin Scale 0–2 at 3 months) was lower (OR 0.58, 95% CI 0.42 to 0.80, P<0.01). The rates of symptomatic intracranial hemorrhage (P=0.37) and successful reperfusion (P=0.47) were comparable among groups. Conclusion: This meta-analysis highlights the significant negative impact of poor HIR on patient outcomes. These findings emphasize the need for personalized treatment strategies for patients with poor HIR.

Background/Objectives: Medulloblastoma is the most common malignant brain tumor in children. In recent decades, the therapeutic landscape has undergone significant changes, with stereotactic radiosurgery (SRS) emerging as a promising treatment for recurrent cases. Our study provides a comprehensive analysis of the long-term efficacy and safety of SRS in recurrent medulloblastomas across both pediatric and adult patients at a single institution. Methods: We retrospectively reviewed the clinical and radiological records of patients who underwent CyberKnife SRS for recurrent cranial medulloblastomas at our institution between 1998 and 2023. Follow-up data were available for 15 medulloblastomas in 10 patients. The cohort comprised eight pediatric patients (ages 3–18) and two adult patients (ages 19–75). The median age at the time of SRS was 13 years, the median tumor volume accounted for 1.9 cc, the median biologically equivalent dose (BED) was 126 Gy, and the single-fraction equivalent dose (SFED) was 18 Gy. The SRS was administered at 75% of the median isodose line. Results: Following a median follow-up of 39 months (range: 6–78), 53.3% of the medulloblastomas progressed, 13.3% regressed, and 33.3% remained stable. The 3-year local tumor control (LTC) rate for all medulloblastomas was 65%, with lower rates observed in the adult cohort (50%) and higher rates in pediatric patients (67%). The 3-year overall survival (OS) rate was 70%, with significantly higher rates in pediatric patients (75%) compared to adult patients (50%). The 3-year progression-free survival (PFS) rate was 58.3%, with higher rates in pediatric patients (60%) compared to adult patients (50%). Two pediatric patients developed radiation-induced edema, while two adult patients experienced radiation necrosis at the latest follow-up, with both adult patients passing away. Conclusions: Our study provides a complex perspective on the efficacy and safety of CyberKnife SRS in treating recurrent cranial medulloblastomas across pediatric and adult populations. The rarity of adverse radiation events (AREs) underscores the safety profile of SRS, reinforcing its role in enhancing treatment outcomes. The intricacies of symptomatic outcomes, intertwined with factors such as age, tumor location, and prior surgeries, emphasize the need for personalized treatment approaches. Our findings underscore the imperative for ongoing research and the development of more refined treatment strategies for recurrent medulloblastomas. Given the observed disparities in treatment outcomes, a more meticulous tailoring of treatment approaches becomes crucial.

Background Hyperintense acute reperfusion marker (HARM) refers to delayed enhancement in the subarachnoid or subpial space on post-contrast fluid attenuated inversion recovery (FLAIR) images. HARM is a measure of blood–brain barrier breakdown, which has been correlated with poor outcomes in patients with acute ischemic stroke with large vessel occlusion (AIS-LVO). We hypothesized that unfavorable venous outflow (VO) would be correlated with HARM after thrombectomy treatment of AIS-LVO. Objective To determine whether poor VO is associated with HARM on follow-up MRI after stroke in patients with AIS-LVO. Methods Patients with AIS-LVO from the prospective CRISP2 and DEFUSE2 studies with a baseline CT angiography (CTA) scan and a follow-up MRI with FLAIR sequence were screened for enrollment. VO was measured on the baseline CTA scan using the cortical venous opacification score (COVES). HARM was determined on FLAIR sequences at the follow-up MRI. The primary outcome was the occurrence of HARM between those with good VO (VO+; COVES 3–6) and bad VO (VO−; COVES 0–2). Results 121 patients were included; 60.3% (n=73) had VO+ and 39.7% (n=48) had VO−. Patients with VO− had higher presentation National Institutes of Health Stroke Scale scores (18 (IQR 12–20) vs 12 (IQR 8–16) in VO+; P6 s volumes (105 (72–142) mL vs 66 (35–95) mL in VO+; P<0.001). VO− patients were more likely to develop HARM after thrombectomy (31% vs 10% in VO+; P=0.003). On multivariable regression analysis, VO− (OR=3.6 (95% CI 1.2 to 10.6); P=0.02) and the presence of any ICH (OR=3.6 (95% CI 1.2 to 10.5); P=0.02) were independently associated with the occurrence of HARM. Conclusions In patients with AIS-LVO, VO− correlated with HARM on post-thrombectomy MRI.