4D flow MRI for noninvasive monitoring of high-flow vascular malformations in neonates and infants: A feasibility study

BackgroundIntracranial high-flow vascular malformations greatly alter neonatal cerebral hemodynamics and can cause significant morbidity and mortality. X-ray digital subtraction angiography (DSA) is the standard of care to assess angioarchitecture and plan for intervention, but exposes patients to radiation and procedural risks, and only allows for subjective interpretation. Objective noninvasive assessment of hemodynamics could improve prognostication. Data on normal or abnormal cerebral hemodynamics in neonates is limited due to the lack of readily available and validated methods. 4D flow MRI may offer noninvasive quantitative assessment of hemodynamic metrics to gain a better understanding of pathophysiology and may one day help to guide endovascular intervention. Here, we explore the feasibility of 4D flow MRI for the assessment of high-flow vascular malformations and present our initial experience.MethodsRetrospective analysis of 4D flow MRI studies was performed for five children with high-flow vascular malformations before and/or after embolization of their lesions. Two raters independently performed the 4D flow measurements: flow rate and peak speed. We compared quantitative measurements with qualitative angiographic findings.ResultsInterrater reliability of flow measurements was high (intraclass correlation coefficient 0.959). Quantitative changes in arterial and venous 4D flow measurements after embolization corresponded with qualitative changes on DSA.Conclusions4D flow MRI is a feasible and precise tool for studying high-flow intracranial vascular malformations in children with safety advantages over DSA. Standardized acquisition protocols and postprocessing methods could facilitate adoption across multiple centers.