Hidden Brain iron content in Sickle cell disease: Impact on Neurocognitive Functions

Abstract Children with sickle cell disease (SCD) are at a high risk for neurocognitive impairment. We aim to quantitatively measure cerebral tissue R2* to investigate the brain iron deposition in children and young adults with SCD in comparison to beta thalassemia major (BTM) and healthy controls and evaluate its impact on neurocognitive functions in patients with SCD. Thirty-two SCD, fifteen BTM and eleven controls were recruited. Multi-echo fast-gradient echo sequence brain MRI was performed and brain R2* values of both caudate and thalamic regions were calculated. SCD patients were examined for the neurocognitive functions. SCD had high iron overload 0.30±0.12 mg/kg/day. 68.9% of SCD had under- threshold IQ, 12.5% had moderate to severe anxiety and 60.8% had depression. There was no differences between SCD, BTM and controls in brain MRI except that left thalamus R2* higher in BTM than both SCD and controls (p=0.032). Mean right caudate R2* was higher in female than male (p=0.044). No significant association between brain R2* and LIC or heart R2* values in SCD. Left caudate R2* directly correlate with age and HbS%, negative correlate with HbA% while right thalamus R2* negatively correlate with transfusion index and among SCD patients. Conclusion: Neurocognitive dysfunction in SCD could not be explained solely by brain iron overload.