The brain represents 2% of the body weight but consumes 20% of the total energy. Therefore, the rate of oxygenextraction and consumption is a sensitive index of brain function and tissue viability. Non-invasive imaging of brain oxygenation and metabolism can provide an early marker in brain diseases such as Alzheimer’s disease, before clinical symptom can be detected. Using a novel pulse sequence, TRUST MRI, the brain’s oxygen extraction fraction (OEF) was measured in three groups of cognitively normal elderly individuals, but with different levels of genetic risk (Apo E) for Alzheimer’s. It was observed that, even in the absence of any clinical symptoms or cognitive deficits, OEF measured with TRUST MRI can already detect a significant reduction in brain oxygen extraction in high-risk individuals. Aside from Alzheimer’s disease, brain metabolic techniques have also found applications in Multiple Sclerosis, aging, neonates, anorexia, glucose transporter deficiency, sickle cell anemia, and cocaine addiction.
Hanzhang Lu, Zixuan Lin, Peter van Zijl, and Marilyn Albert
Department of Radiology, Johns Hopkins University School of Medicine
F.M. Kirby Research Center for Functional Brain Imaging at Kennedy Krieger Institute