Treatment Strategies and Related Outcomes for Brain Arteriovenous Malformations in Children: A Systematic Review and Meta-Analysis.

OBJECTIVE. The objective of this study was to assess the available evidence in the literature regarding treatment outcomes for pediatric patients with brain arteriovenous malformation (bAVM) with the aim of providing practice guidelines for treatment decisions and highlighting research areas that need attention. MATERIALS AND METHODS. Keyword searches for studies published from January 1, 1981, to April 16, 2018, were performed in MEDLINE, Embase, and Web of Science. Predefined inclusion criteria were used to identify studies. Poisson regression analysis for associations between patient and bAVM characteristics and treatment outcomes. RESULTS. We identified 34 articles comprising 2158 children with bAVM who underwent treatment or observation. The mean age of the study cohort was 12.0 ± 1.6 (SD) years, and 48.1% of the patients were female; 64.3% of bAVMs were hemorrhagic at presentation. The mean follow-up was 50.6 ± 32.3 months. Overall, the meta-analysis of pooled data showed an obliteration rate of 69.8% (95% CI, 62.9-75.9%), recurrence rate of 2.2% (95% CI, 1.1-4.3%), and mortality rate of 2.4%. The pooled complication rate was 22.5% (95% CI, 15.7-31.1%) after surgery, 26.4% (95% CI, 15.2-41.9%) after embolization, and 27.1% (95% CI, 18.1-38.4%) after radiosurgery. Mortality was not associated with age, sex, or hemorrhage; however, recurrence after treatment was inversely associated with age. Complication and mortality rates were reduced for multimodal treatments. For patients with bAVM treated with observation only, complication and mortality rates were 35.9% and 23.5%, respectively. CONCLUSION. Multimodality treatments for pediatric bAVM had lower mortality and complication rates than individual treatments. However, there is a lack of evidence for long-term outcomes. The mortality rate was highest in conservatively managed patients (i.e., observation only). Further research directly comparing different treatment modalities for recurrence and complications is warranted. Gathering data prospectively through multiinstitutional registries will be key to provide strong evidence.

Rotational Vertebrobasilar Insufficiency: Is There a Physiological Spectrum? Phase-Contrast Magnetic Resonance Imaging Quantification in Healthy Volunteers.

BACKGROUND: Some cases of cerebral ischemia have been attributed to dynamic flow limitation in neck vessels. It however remains unknown whether this represents the extreme end of a physiological response. METHODS: Eighteen healthy volunteers were recruited to this prospective study. Cervical blood flow (ml/min/m2) was assessed using phase-contrast MRI, and cerebral perfusion ratios were assessed using arterial spin labeling perfusion at neutral position, predefined head rotations, as well as flexion and extension. Inter-reader agreements were assessed using intraclass correlation coefficient. RESULTS: The mean age was 38.6 ± 10.8 (range = 22-56) years, for five male participants and 13 females. The means for height and weight were 168 cm and 73.2 kg, respectively. There were no significant differences in individual arterial blood flow with change in head position (P > 0.05). Similarly, the repeated-measures analysis of variance test demonstrated no significant difference in perfusion ratios in relation to head position movement (P > 0.05). Inter-reader agreement was excellent (intraclass correlation coefficient = 0.97). CONCLUSIONS: There is neither significant change in either individual cervical arterial blood flow nor cerebral perfusion within the normal physiological/anatomical range of motion in healthy individuals. It is therefore reasonable to conclude that any such hemodynamic change identified in a patient with ischemic stroke be considered causative.

MRI Phase-Contrast Blood Flow in Fasting Pediatric Patients with Fontan Circulation Correlates with Exercise Capacity.

Purpose: To assess regional blood flow in fasting pediatric patients with Fontan circulation by using MRI and to explore associations with clinical parameters. Materials and Methods: In this retrospective study, pediatric patients who had undergone the Fontan procedure (<18 years of age) and had undergone clinical cardiac MRI, performed after at least 4 hours of fasting, between 2018 and 2021 were included. Regional blood flow was compared with published healthy volunteer data (n = 19) and assessed in relation to hemodynamic parameters and clinical status. Data are presented as medians, with first to third quartiles in parentheses. Mann-Whitney U, Kruskal-Wallis, χ2, and Spearman rank correlation tests were used. Results: Fifty-five patients (38 boys) with median age at MRI of 14 years (IQR, 11-16 years) and median time from Fontan procedure to MRI of 10 years (IQR, 8-12 years) were included. Patients after Fontan procedure had lower ascending aortic, inferior vena cava, and total systemic blood flow compared with healthy volunteers (3.00 L/min/m2 [IQR, 2.75-3.30 L/min/m2] vs 3.61 L/min/m2 [IQR, 3.29-4.07 L/min/m2]; 1.73 L/min/m2 [IQR, 1.40-1.94 L/min/m2] vs 2.24 L/min/m2 [IQR, 2.06-2.75 L/min/m2]; 2.78 L/min/m2 [IQR, 2.45-3.10 L/min/m2] vs 3.95 L/min/m2 [IQR, 3.20-4.30 L/min/m2], respectively; P < .001). Portal vein flow was greater than hepatic vein flow in 25% of patients. Fontan blood flow was inversely correlated with pre-Fontan mean pulmonary artery pressure (Spearman rank correlation coefficient [rs ]= -0.42, P = .005) and ventricular end diastolic pressure (rs = -0.33, P = .04) and positively correlated with post-Fontan percent predicted oxygen consumption at peak workload (rs = 0.34, P = .02). Conclusion: Reference ranges are provided for regional systemic blood flow derived by using MRI in fasting pediatric patients with Fontan circulation, who had lower systemic blood flow compared with healthy volunteers. Lower fasting Fontan blood flow correlated with lower exercise capacity.Keywords: Pediatrics, Heart, Congenital, MR Imaging, Hemodynamics/Flow Dynamics, Cardiac Supplemental material is available for this article. © RSNA, 2022.