New blood flow measurement method using color Doppler signals -estimating its validity using phantom and mesuring in surface vessels and abdominal arteries-

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Ultrasonic estimation of flow volume has conventionally been made by multiplying a cross-sectional area of a vessel by a maximum flow velocity through the area as determined by pulsed Doppler method and then by correcting the product by a certain coefficient. This method, however, have some difficulties. We examined using a phantom and a dog the validity of a new flow volume measurement by color flow signals.The method firstly involved a formation of a velocity profile on a line that passes the center of a vessel and that is perpendicular to the long axis of the vessel. Then the cross section of the vessel being deemed circular, the profile is developed into a two-dimensional distribution. In doing so, each half of the linear profile are treated differently to avoid an error that might be brought by an eccentric peak. A flow volume at a given moment can thus be calculated by multiplying each velocity by number of pixels in that velocity and by adding up the products. A flow volume per one cardiac cycle can then be calculated by integrating flow volumes at amount for the cycle. Results thus obtained showed a good correlation with those of the actual flow volume through not only the phantom but also a dog (r=0.9).We also estimated portal venous flow. The flow profiles in the main portal vein and right anterior branch were depicted peak flattening shaped, which was previously reported parabolic by the pulsed Doppler method. Estimating by color Doppler method, spiral flow was demonstraed in the left branch of the potal vein.Shear rate of the carotid artery are estimated by using this methos. They revealed high ratio near the wall and low ratio center of the vessels non-invasively.