1.4\ Color Doppler Flow Image

of the Abdominal Aorta

RL

IVC

Ao

RL

IVC

Ao

Fig. 9.4  Color Doppler flow image of the abdominal aorta

1.4.1\ Scanning Method

The views are the same as those shown in Figs. 9.1 and 9.2. Color Doppler is started after grayscale evaluation of the Ao. The gain, filter,

and scale parameters should be adjusted during the examination to get the best image. On the longitudinal view, pressing the caudal part of the probe may be helpful if the blood signal cannot be shown properly on the image because of the large echo–blood angle.

1.4.2\ Section Structure

The structures are the same as those shown in Figs. 9.1, 9.2, and 9.3, with a longitudinal view of the Ao and IVC.

1.4.3\ Measurement Method and Normal Value

On the longitudinal view of the AA, the normal blood flow direction is from celiac to caudal; a color Doppler signal fills the whole lumen with a bright color in the middle of the vessel and a relatively dark color adjacent to the vessel wall. On the transverse or coronal section, the blood flow directions of the Ao and IVC should be opposite.

1.4.4\ Clinical Application Value

The brief observation of blood flow by color Doppler flow imaging is helpful to determine a local or diffused lumen stenosis. The aliasing color signal at a severe stenosis can be used to determine the position and blood flow direction of the stenosis. For a plaque with a very low echo or attached thrombosis in an aneurysm, color Doppler is useful to determine the thickness of the lesion and to measure the residual lumen accurately.