Assessing abnormal oxygen extraction fraction (OEF) and neural tissue susceptibility in Parkinson’s Disease

Motivation: Although Parkinson's disease (PD) is highly prevalent, its pathophysiology, particularly abnormal oxygen extraction fraction (OEF) and neural tissue susceptibility ($$$\chi_{n}$$$ ), remains unclear. Goal(s): Compare OEF and $$$\chi_{n}$$$ between PD and healthy control (HC) and investigate their associations with age (PD risk factor) and cognitive impairment (measured by MMSE). Approach: A novel MRI technique, QQ, estimates OEF and $$$\chi_{n}$$$ in cortical(CGM) and deep gray matter(DGM). Results: PD showed higher OEF and $$$\chi_{n}$$$ than HC. In PD, OEF was associated negatively with $$$\chi_{n}$$$ in CGM and positively with MMSE in DGM. In both PD and HC, $$$\chi_{n}$$$ was associated positively with MMSE and age. Impact: This study demonstrates QQ's feasibility for detecting abnormal oxygen metabolism and iron accumulation in PD. Using a single routine MRI sequence, QQ is readily applicable for investigating PD pathophysiology and other neurologic disorders.