Abstract

Discrepancies for the range of normal values in the currently available transcranial color-coded Doppler sonography studies, as well as in those looking at the effect of age distribution on blood flow parameters in the basal cerebral arteries prompted a study of transcranial color-coded Doppler sonography in a group of healthy subjects of wide age distribution. 182 healthy volunteers, meeting strict selection criteria - 79 males, mean age 47 yr (range 20-78 yr) and 103 females, mean age 47 yr (range 22-86 yr) - were examined via temporal acoustic windows with a 2.5 MHz transcranial probe (Toshiba SSH 140). Volunteers were grouped by age: 20-40 yr; 41-60 yr and over 60 yr. Angle-corrected peak systolic, end-diastolic and mean velocities, and the resistivity and pulsatility indices were determined in anterior (ACA), middle (MCA) and posterior (PCA) cerebral arteries from the Doppler waveforms. Of 1092 arteries 983 were successfully insonated. Mean angles of insonation for anterior, middle and posterior cerebral artery were: 36¡± 18¡ (SD); 29¡±14¡, 39¡±19¡ respectively. Age stratified velocity data for the mean velocities (vm) of MCA, ACA and PCA (mean in cm/s±SD) were: 20-40yr - 81±20, 56±14, 52±12; 41-60 yr - 73±19, 53±16, 51±12; >60 yr - 59±11, 44±11, 40±9; in all subjects the mean velocities were 73±20, 53±15, 49±12; respectively. There was a significant decline with age in all blood flow velocities in all vessels.The reduction in flow velocity with age was most pronounced over the age 40 yr. (e.g. mean velocity of middle cerebral artery, F=15.7; in groups: 20-40/41-60 p<0.05; 20-40/>60 p<0.001; 41-60/>60 p<0.01; ANOVAI test) and in MCA r="-0.45" as compared to PCA r="-0.42" and ACA r="-0.30." Vm's in all vessels were higher in females than in males (ACA, F="7.6," p<0.001; MCA, F="9.1," p<0.01, PCA, F="4.5," p<0.05) although these differences were not statistically significant in the groups 40-60 yr and over 60 yr. The range of blood flow velocities in basal cerebral arteries in healthy subjects was found to be wide and significantly age dependent. From our results it is clear that proper age- and sex matching of transcranial color-coded Doppler sonography data is a prerequisite of any clinically relevant data.

Keywords: blood flow velocities