Studies on cerebral circulation by the ultrasonic Doppler technique--with special reference to clinical application of the technique

Prediction of hemispheric blood flow from carotid velocity measurements. A study with the Doppler and 133Xe inhalation techniques

Doppler carotid velocity determinations were related to hemispheric blood flow measurements by the 133Xe inhalation method in 28 patients with psychiatric disorders without arterial pathology and in 2 normal subjects. Results from 39 double determinations showed a product-moment correlation of 0.88 (p < 0.001) between right hemispheric blood flow and right internal carotid end-diastolic velocity. The correlation for the left side was slightly lower (r = 0.83), while the common carotid end-diastolic velocity showed a considerably lower correlation of 0.71 (rt) and 0.69 (lt) respectively. The peak-systolic velocity values (internal carotids) showed a less close relationship to hemispheric flow (r = 0.71 (rt) and r = 0.61 (lt)). It is concluded that a fairly accurate (15-20% maximum error) prediction of hemispheric blood flow from Doppler internal carotid end-diastolic velocity values is possible in patients without abnormalities in these arterial systems. The high correlations found, in spite of the fact that arterial diameters were not taken into account, are further proof of the accuracy and validity of both methods.

Circulatory effect of respiratory maneuvers

The circulatory effects of three kinds of respiratory maneuvers--maximum breathing, voluntary hyperventilation, and the Valsalva maneuver--on cerebral blood flow, brachial blood flow, heart rate, and systolic blood pressure were investigated by means of the on-line Doppler ultrasonic technique in 20 men. Arterial gas contents (PO2, PCO2, pH) were also examined. Cerebral blood flow was increased or showed the biphasic response (increase in the former and decrease in the latter part of the maneuver) with maximum breathing. Cerebral blood flow was decreased with voluntary hyperventilation. The cerebral blood flow was maintained at a same level during the maneuver or tended to return to the control level. Cerebral blood flow was decreased in the Valsalva maneuver. There was a transient but conspicious increase of the cerebral blood flow immediately after the maneuver.

Differentiation of the dementias of old age by ultrasonic doppler flowmetry: a pilot study

At the Bel-Air Psychiatric Clinic, Geneva, Switzerland, the technique of ultrasonic Doppler flowmetry was used to examine the internal carotid arteries of 30 aged patients - 10 with cerebral degenerative dementia, 10 with cerebrovascular dementia, and 10 without dementia. An index of cerebrovascular resistance was calculated. Apparently this index can distinguish a group of vascular dementias from a group of degenerative dementias.