Correlations between cerebral pool transit time method of radioactive non diffusible tracer and cerebral electrical impedance plethysmography

Abnormal features of craniocerebral rheographic tracings are observed, together with a prolonged pool cerebral transit time, in cases of diffuse or regional cerebrovascular diseases. Abnormal rheographic features, with cerebral pool transit time still in the normal range, were observed in patients where cerebrovascular damage was not relevant in comparison with the pathological involvement of the remaining general circulation. No satisfactory quantitative correlation was found between cerebral pool transit time and the simultaneously registered craniocerebral rheographic tracings. The authors report observed values of blood volume, stroke volume, cardiac output, mean general circulation time obtained by isotopic dynamic studies with radioalbumin, as well as amplitude, pulse velocity and planimetry of the rheoencephalographic curve integrated for a time equal and simultaneous to the cerebral pool transit time.