Relationship between cerebrovascular risk factors and oxygen metabolic stress in a cognitively impaired population:...

Cerebrovascular risk factors contribute to cognitive decline via mechanisms such as small vessel disease and chronic ischemia. Advanced MRI parameters, including maximum oxygen extraction fraction (OEF^max) and cerebral metabolic rate of oxygen (CMRO₂), provide insights into cerebral oxygenation and cognition. This retrospective study evaluated the relationships between oxygen metabolic stress, cerebrovascular risk factors, and cognitive function in 226 adults undergoing dynamic susceptibility contrast (DSC)-MRI. White matter hyperintensity (WMH) volumes, OEF^max, and CMRO₂ were quantified and analyzed against cerebrovascular risk factors (e.g., age, smoking, hypertension), MMSE scores, clinical diagnoses, and history of cerebrovascular disease. A history of smoking was linked to a higher OEF^max (P = 0.015). An older age correlated with a larger WMH volume (P < 0.001), higher OEF^max (P < 0.001), and lower CMRO₂ (P = 0.001). Patients with history of infarcts exhibited larger WMH volumes (P < 0.001) and lower CMRO₂ (P < 0.001). Multivariable regression showed WMH volume (P = 0.03) and OEF^max (P = 0.018) were negatively associated with MMSE scores, while CMRO₂ had no significant association (P = 0.52). Patients with vascular dementia exhibited lower CMRO₂ than those with Alzheimer's or mild cognitive impairment (P = 0.001). These findings suggest that DSC-derived OEF^max and CMRO₂ could provide insights into the relationship between cerebrovascular risk factors and cognitive decline, emphasizing their role as key indicators of brain oxygenation.