Abstract only Introduction: While some brain arteriovenous malformations (bAVM) demonstrate long-term stability, others demonstrate dynamic changes (new aneurysms or venous outflow stenosis) that ...confer higher rupture risk even after apparent cure. The objective of this study is to evaluate the feasibility and efficacy of 4D Flow MRI to quantitatively assess the hemodynamic changes in pediatric bAVMs following treatment and its use for early detection of high-risk changes. Methods: We have prospectively enrolled 20 children (mean age 11.8 ± 3.8 years) with bAVM into a single center cohort study. 4D Flow MRI was acquired in a transverse slab covering the circle of Willis using prospective gating, compressed sensing, and a resolution of 0.7 x 0.7 x 1.0 mm 3 on a 3T GE Discovery MR750 scanner. MRI at baseline and post-intervention (6-month and 1-year follow up) has been acquired for 5 patients thus far. 4D Flow data was post-processed by segmenting the main cerebral arteries and calculating cardiac-averaged flow rates in cross-sections orthogonal to the centerline of each vessel segment. Results: The flow rate accuracy was evaluated by calculating the flow conservation at the right/left internal carotid and basilar junctions, yielding average errors of 10.7% ± 12.7, 14.0% ± 9.5, and 19.3% ± 13.8 respectively. The hemisphere containing the bAVM received an average of 57.2% ± 2.8 of total brain flow at baseline, which decreased to an average of 51.2% ± 2.9 1-year follow-up. In 2 of 5 patients, the flow laterality between hemispheres flipped post-intervention with increased flow to the contralateral hemisphere. In all the post-intervention studies, we observed a decrease in flow and maximum velocities, as well as an increase in pulsatility index, in the primary feeding arteries to the bAVM (Figure). Conclusion: These preliminary results indicate that 4D Flow MRI may be a robust and useful tool for monitoring changes in intracranial flow patterns after bAVM treatment in children.
Abstract only Introduction: Structural changes following intracerebral hemorrhage (ICH) caused by ruptured brain vascular malformations (VMs) remain poorly understood. We conducted a longitudinal ...study to examine changes across ipsilesional and contralesional hemispheres after unilateral ICH, mainly in the temporoparietal area. Methods: Brain MRI was acquired in 8 patients aged 8-18 years ( Mean =15.13, SD =3.18) at presentation of ICH prior to treatment (baseline/Session 1) and repeated at 6 months (Session 2) and 12 months (Session 3) post-treatment. Using FreeSurfer 7.4.0, T1 and T2 FLAIR MR images were segmented into cortical and subcortical regions, with gray matter (GM) parcellated based on the DKT atlas. SynthSeg refined lesion extraction for more precise measurements of brain volume. Volume changes were quantified as percent change from baseline with signed values denoting increase or decrease. Pearson correlation and permutation testing ( n =5000) evaluated associations of homologous versus non-homologous regions. Results: There were significant correlations between the volume changes of homologous GM regions, for both Session 2 ( R =0.57, p <0.001) and Session 3 ( R =0.50, p <0.001), and of homologous GM in hemispheric lobes (Session 2: R =0.69, p <0.001; Session 3: R =0.67, p <0.001). Permutation tests confirmed that correlations of volume changes were greater for homologous than non-homologous regions and lobes for Sessions 2 and 3 ( p <0.001 except Session 3 lobes: p =0.016). Conclusions: We observed structural covariance of volume changes between homologous regions, most pronounced in the first 6 months after unilateral ICH. This indicates network-mediated distant effects of ICH, with atrophy reflected by diaschisis and volume recovery mirrored by positive neuroplasticity of contralateral homologs. Lesion-network mapping with correlation to long-term outcome would elucidate the effects of this long-range neuroplasticity following pediatric ICH.
Knowledge-based tools used to standardize perioperative care, such as the shunt infection prevention protocol of the Hydrocephalus Clinical Research Network (HCRN), have demonstrated their ability to ...reduce surgeon-based and center-based variations in outcomes and improve patient care. The mere presence of high-quality evidence, however, does not necessarily translate into improved patient outcomes owing to the implementation gap. To advance understanding of how knowledge-based tools are being utilized in the routine clinical care of children with hydrocephalus, the HCRN-Quality (HCRNq) network was started in 2019. With a focus on CSF shunt infection, the authors present baseline data regarding CSF shunt infection rates and current shunt infection prevention practices in use at HCRNq sites.
Baseline shunt surgery practices, infection rate, and risk factor data were prospectively collected within HCRNq. No standard infection protocol was recommended, but site use of a protocol was implied if at least 3 of 6 common shunt infection prevention practices were used in > 80% of shunt surgical procedures. Univariable and multivariable analyses of shunt infection risk factors were performed.
Thirty sites accrued data on 2437 procedures between November 2019 and June 2021. The unadjusted infection rate across all sites was 3.9% (range 0%-13%) and did not differ among shunt insertion, shunt revision, or shunt insertion after infection. Protocol use was implied for only 15/30 centers and 60% of shunt operations. On univariable analysis, iodine/DuraPrep (OR 0.57, 95% CI 0.37-0.88, p = 0.02) and the use of an antibiotic-impregnated catheter in any segment of the shunt (or both) decreased infection risk (OR 0.53, 95% CI 0.34-0.82, p = 0.01). Iodine-based prep solutions (OR 0.56, 95% 0.36-0.86, p = 0.02) and the use of antibiotic-impregnated catheters (OR 0.52, 95% CI 0.34-0.81, p = 0.01) retained significance in the multivariable model, but no relationship between protocol use and infection risk was demonstrated in this baseline analysis.
The authors have demonstrated that children undergoing CSF shunt surgery at HCRNq sites share similar demographic characteristics with other large North American multicenter cohorts, with similar observed baseline infection rates and risk factors. Many centers have implemented standardized shunt infection prevention practices, but considerable practice variation remains. As such, there is an opportunity to decrease shunt infection rates in these centers through continued standardization of care.
