Blood flow in deep abdominal and pelvic vessels: ultrasonic pulsed-Doppler analysis.

Abstract

Ultrasonic pulsed-Doppler signals from deep-lying vessels in the normal abdomen and pelvis are described. The signal characteristics combine to produce a Doppler "signature" that is specific for each vessel. The clinical potential of this method of deep flow detection is considered in relation to three areas of Doppler signal analysis: first, qualitative indication of the presence, direction, or absence of flow in a structure; second, more quantitative description of time velocity waveforms and Doppler spectral content; and third, the estimation of absolute volume flow. Limitations of these methods for the abdominal signals obtained are discussed.

Role for Doppler Ultrasound in the Assessment of Renal Circulation: Effects of Dopamine and Dobutamine on Renal Hemodynamics in Humans

“…Thus, blood flow is proportional to the square of the diameter, and the diameter is potentially a factor that can lead to measurement errors of renal blood flow. Vessel diameter will also vary with arterial pulsation, and even if the diameter is precisely determined, the velocity profile is not homogeneous in a relatively narrow vessel like the renal artery [16]. Accordingly, the difference between degrees of changes in the mean velocity and the ERBF may be due to changes in vessel diameter of the measuring site.…”

Ultrasonographic Examination of Some Vessels in Dogs and the Characteristics of Blood Flow in These Vessels

“…The subsequent diastolic reverse flow is due to blood rebounding up the aorta as the velocity wave is reflected from the high impedance of the peripheral vascular bed of the hind limbs [15]. As the vessel diameter returns to normal, the rebound energy provides the necessary energy to promote continuous flow in diastole [6,14].…”

Performance tests of Doppler ultrasound equipment with a tissue and blood-mimicking phantom.

“…Circulating through these vessels is a blood-mimicking fluid. The fluid is a mixture of degassed water and glycerol in correct proportions to give a specific gravity of 1.043 g/cm 3 • This specific gravity was chosen toreduce sedimentation of the third component of the blood-mimicking fluid 1 The concentration of microspheres to yield the same backscatter levels as blood was found empirically using the apparatus shown in Figure 2. Outdated whole human blood having a hematocrit of 43 was circulated through a pancake-shaped reservoir having acoustic windows of Saran• (Dow Chemical Corp., Midland, MI).…”