Balloon Modeling of BOLD Responses in Children with Sickle Cell Anemia (SCA)

Robert Ogg¹, Ping Zou¹, Winfred Wang¹, Russel Ware¹, Kathleen Helton¹

Elevated resting cerebral blood flow in SCA patients may decrease detection of activation with fMRI. We used fMRI during visual stimulation to characterize the hemodynamic responses in children with SCA. Detection, magnitude of BOLD signal, and activation volume were significantly lower in SCA patients than control subjects. Modeling showed that differences in the BOLD response were accounted for by differences in CBF response, oxygen extraction fraction during stimulation, CBV, and vascular mechanical characteristics. These findings suggest that the balloon model is useful to relate altered BOLD response to important clinical and physiological parameters in patients with SCA.