Cerebral Hemodynamics in Patients with Risk Factors for Arteriosclerosis (Hypertension or Diabetes Mellitus) —Transcranial Doppler Study—

To examine the effects of risk factors for arteriosclerosis on cerebral vasculature, 1) we performed transcranial Doppler sonography (TCD) in patients with different stages of hypertension and 2) compared the TCD measurements with cerebral hemodynamics determined by positron emission tomography (PET) .1) Sixteen chronic hypertensives with chronic and small brain infarction, 10 young early-stage hypertensives and 16 young normotensive volunteers were studied. We measured mean blood flow velocity, Gosling's pulsatility index (PI), Fourier PI1 (Fourier PI of the first harmonic) and cerebrovascular resistance of the middle cerebral artery (MCA) . The early-stage hypertensives demonstrated higher velocity, normal Fourier PI1and near normal resistance, whereas the chronic hypertensives showed near normal velocity, higher Fourier PI1 and greater resistance. Results may indicate the difference in severity of cerebral arteriopathy between the early and late stages of hypertension.2) In 19 patients with brain infarction, hypertension and/or diabetes mellitus, blood flow velocity and CO2vasomotor response (VMR) of the MCA were measured by TCD and compared with the PET parameters. Blood flow velocity and cerebral blood flow (CBF) were significantly correlated in the MCA territory. CO2VMR was more closely correlated with the ratio of CBF to cerebral blood volume, indicating brain perfusion pressure, in each region.