[Cerebral blood flow disorder in elderly patients with diabetes mellitus]

We studied changes due to aging in carotid and cerebral arterial blood flows, and compared the difference between healthy adults and diabetics using a ultrasonic quantitative blood flow measurement system (QFM 2000 XA). Aging caused the carotid blood flow, blood velocity and diameter excursion rate on the carotid wall to decrease, and its diameter to enlarge. Both cerebrovascular resistance and capacitance obtained from simulation models of blood pressure waves, increased with aging. Cerebral blood flows in aged healthy adults was not significantly different from those in aged diabetics, but clearly different from those in aged diabetics with abnormal findings on MRI. When right and left cerebral blood flows were markedly different, abnormality was observed on brain MRI. This well agreed with findings on cerebral blood flow scintigrams (SPECT) obtained from several patients. The ultrasonic quantitative blood flow measurement system is considered a useful screening tool before CT or MRI examinations.