Estimation of Cerebral Oxygen Extraction Fraction (OEF) by Haematocrit-Corrected QQ (QSM + qBOLD) in Sickle Cell Anaemia

Motivation: Cerebral injury in Sickle cell anaemia (SCA) is hypothesised to be caused by an inability to maintain stable oxygen delivery to tissue. A biomarker of tissue vulnerability is the cerebral metabolic rate of oxygen consumption (CMRO2). Goal(s): Estimate regional Oxygen Extraction fraction (OEF) and CMRO2 in participants with SCA and healthy controls using non-invasive regional MRI. Approach: QQ (QSM + qBOLD) was used to estimate voxel-wise OEF - enabling calculation of regional CMRO2. Results: SCA participants had significantly higher cerebral blood flow and OEF compared to controls. CMRO2 was higher in white matter in children, but not adults, with SCA. Impact: QQ (QSM + qBOLD) enables a non-invasive method of studying haemodynamic health via regional estimation of OEF and CMRO2 in participants, of all ages, with SCA. The differences found suggest the important role of cerebral metabolism in tissue injury.