1.5\ Doppler Spectrum

of the Abdominal Aorta

Fig. 9.5  Doppler spectrum of the abdominal aorta

1.5.1\ Scanning Method

The method is the same as that shown in Sect. 1.1.1, and 1.4.1. Start to get a Doppler spectrum after a high-quality color Doppler flow image is accomplished. On the longitudinal view, press the caudal part of the probe to reduce the echo– blood angle in order to reduce the error in the blood flow velocity.

1.5.2\ Section Structure

Longitudinal view of the Ao; the normal blood flow direction is from celiac to caudal.

1.5.3\ Measurement Method and Normal Value

The typical Ao spectrum has a steep systolic upgrade, narrow spectrum band, and clear spectrum window; the spectrum pattern differs according to the position. A certain level of positive diastolic blood flow can be seen at the upper segment, and a reverse pulse of the early diastolic spectrum is typical at the lower segment of the Ao. The peak systolic velocity (PSV) of the Ao is reported to be 50–110 cm/s; there is a slight decrease in the PSV from the upper to lower segment.

1.5.4\ Clinical Application Value

In the case of a stenosis, the PSV increases at the stenosis and decreases distant from the stenosis with a decreased acceleration velocity, prolonged acceleration time, and blunt spectrum.