Computational Fluid Dynamics Analysis of Cerebrovascular Hemodynamic Differences in Adults with Sickle Cell Disease: Comparing Stroke and Non-Stroke Cohorts

Abstract Purpose Sickle cell disease (SCD) is a debilitating genetic disorder affecting hemoglobin in red blood cells. Patients with SCD are at risk of cerebrovascular disease in the Circle of Willis (CoW), with strokes occurring from early childhood into adulthood. Despite this lifelong risk, stroke prevention guidelines using transcranial Doppler ultrasound (TCD) exist only for children, leaving a critical gap for adults. This study aimed to characterize cerebral hemodynamics in the CoW of adults with SCD to support future risk stratification and treatment guidelines. Methods Numerical simulations were performed using 3D vascular geometries segmented from high-resolution, patient-specific magnetic resonance imaging in healthy controls (n=3), SCD patients without stroke (n=3), and SCD patients post-stroke (n=3). Key hemodynamic parameters including time-averaged wall shear stress (TAWSS), surface area exposed to low or high WSS, time-averaged mean of maximum velocity (TAMMV), and pressure drop across the CoW were quantified and compared. Results Preliminary results show distinct hemodynamic differences were observed across groups. SCD patients post-stroke had lower TAMMV at TCD-equivalent CoW locations (except one with ICA stenosis), the lowest average TAWSS, and the greatest surface area exposed to WSS 1 Pa. In contrast, SCD patients without stroke had the highest TAWSS and greatest area exposed to WSS >7 Pa. Despite similar total cerebral blood flow to controls, post-stroke patients showed a lower pressure drop across the CoW. Conclusions Patient-specific simulations can quantify cerebral hemodynamics in adults with SCD, offering insight into stroke-related changes and informing future stroke risk assessment and personalized treatment strategies.