Cerebrovascular disease and PET

Abstract

Positron emission tomography (PET) and O-15 tracers have been used greater than 30 years to evaluate human cerebral hemodynamics in patients with cerebral vascular disease (CVD). Quantitative measurement of cerebral blood flow (CBF) and metabolism is important because critical impairment of cerebral circulation induces irreversible damage to the cerebral cortex, causing neuronal deficits or functional damage. The cerebral regions of impaired hemodynamics, also referred to as misery perfusion are visualized by mismatch between oxygen metabolism and CBF (Lenzi et al. J Neurol Neurosurg Psychiatry 41:11-7, 1978; Baron et al. Stroke 12:454-9, 1981), which is usually delineated by the elevation of oxygen extraction fraction (OEF) in O-15 gas PET (Baron et al. Stroke 12:454-9, 1981; Powers et al. Ann Neurol 16:546-52, 1984; Powers and Raichle Stroke 16:361-76, 1985; Powers et al. Ann Intern Med 106:27-34, 1987; Powers Ann Neurol 29:231-40, 1991). Because patients with misery perfusion show a significantly higher incidence rate of stroke or recurrent stroke (Yamauchi et al. J Neurol Neurosurg Psychiatry 61:18-25, 1996; Yamauchi et al. J Nucl Med 40:1992-8; Grubb et al. JAMA 280:1055-60), evaluation of hemodynamic status in CVD patients is very important to determine indication of neurosurgical treatment. To quantitatively evaluate cerebral hemodynamic status, methods for precise measurement were developed and its accuracy has also been improved with the progression of PET scanner resolution.