Abstract
The relationship of common carotid blood flow volume to aging and dementia was studied using a new ultrasonic Doppler blood flow-meter which enables the measurement of carotid blood flow volume under monitoring of the diameter of the common carotid artery on the B-mode image. Prior to studies in clinical cases the reliability of this equipment was examined using canine carotid artery. A positive linear correlation of y=0.92x+8.6 (r=0.78, n=45, p<0.01) was obtained between the blood flow volumes determined by electromagnetic flow-meter (x) and ultrasonic flow-meter (y). As clinical studies mean blood flow volume, velocity and vessel diameters of both common carotid arteries were measured in 5 young controls in the 20's (mean 25.4 years) and 30 elders ranging from 71 to 98 years in age who presented points less than 7 in Hackinski's Ischemic Socre. Also the mean systemic blood pressure and cerebrovascular resistance were measured. The mean blood flow volume and velocity of both common carotid arteries were 7.77±0.31ml/sec, 8.47±0.75ml/sec, 18.77±0.23cm/sec, 22.24±2.24cm/sec, in the 20's; 4.46±1.77ml/sec, 4.43±1.51ml/sec, 9.25±2.35 cm/sec, 9.04±4.00cm/sec in the 70's; 4.12±1.25 ml/sec 3.92±0.98ml/sec, 9.19±2.27cm/sec, 8.96±1.72cm/sec in the 80's and 3.62±0.26ml/sec, 3.67± 0.12ml/sec, 8.46±2.31cm/sec, 7.41±0.86cm/sec in the 90's showing significant difference (p<0.01) between the 20's and all eldery groups above 70 years old. The mean diameter of the common carotid artery showed increase in the elderly groups compared with the 20's although without significance. Cerebrovascular resistance showed increase in accordance with aging presenting significant difference between the 20's and elderly groups above 70 years in age (5.27±0.20mmHg/ml/sec vs 9.62±1.91mmHg/ml/sec, 11.93±3.10mmHg/ ml/sec, 12.97±1.73mmHg/ml/sec, p<0.01 for each). Considering factors other than aging, Hasegawa's dementia scale test was performed in 21 subjects and a positive linear correlation of y=0.21x+4.86 (r=0.72, p<0.01) was obtained between scores of Hasagawa's dementia scale (x) and the sum of both common carotid arterial blood flow volumes (y).
