The quantitative blood velocity of MCA (Ml and M2) and BA was noninvasively measured by utilizing the color capture method (CC method) for the transcranial color flow images (TC-CFI) . This CC technique, which was supplied by ATL Ultramark 9, featured a display of one projected image of the CFIs which were memorized in one cine-loop during the displacement of the probe along the axis perpendicular to the horizontal image of the brain. This projected image indicating cerebral arteries and veins was very useful in setting the Doppler sample volume for the desired artery. Also the image could be used to determine the Doppler beam angle for the velocity calculation which could not be actualized in the TCD application.
The velocity of Ml was measured at a distal location 3 cm from the ACA-MCA bifurcation through the temporal bone. Also M2 velocity was measured at a distal location 2 cm from the M1-M2 bifurcation. The BA velocity was measured at 1.5 cm from the junction of both vertebral arteries.
The data obtained from 13 young subjects (mean age : 20.7 y.o.) were
mean M 1 velocity : 42.7 ±6.7 cm/s
mean M2 velocity : 24.9± 8.8 cm/s
mean BA velocity : 18.6±4.1 cm/s
The mean velocity was calculated by multiplying 0.5 to the mean velocity of the peak velocity pattern over one cardiac cycle of the Doppler sonogram, in order to compensate the parabolic velocity profile in the vessel lumen.
It was also verified through TC-CFI and CC methods that the Doppler beam angular correction technique was indispensable in the velocity measurement of MCA on the temporal bone. On the contrary, this angular corection technique was not necessary in the BA measurement in the occipital region, because the velocity error due to the beam angle was minimal. Accordingly it was noticed that previous data concerning BA could be used as the true blood velocity within a permissible error.
The above data can be used as the standard value of MCA and BA flow velocity of young adults.
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