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A N A T O M Y FOR DIAGNOSTIC I M A G I N G
Ultrasound
Magnetic resonance imaging
The IVC can be identified where it is not obscured by intestinal gas. Its hepatic and proximal courses are readily seen with ultrasound. It can be seen posterior to the portal vein at the epiploic foramen. The hepatic veins can be seen draining to the IVC before it enters the right atrium. The IVC curves ventrally just before piercing the diaphragm, unlike the aorta, which passes posterior to the diaphragm.
The IVC and its tributaries can be non-invasively visualized by a few coronal and sagittal sections without the need for contrast.
Computed tomography The IVC is seen on the right of the aorta. It is a transverse oval in cross-section but its shape varies from slit-like on inspiration to circular on expiration. The right adrenal gland is seen to be partly posterior to the IVC. Some liver tissue may also be found posterior to it in its upper course. The right aortic branches that pass behind the IVC are usually visible. The union of the common iliac veins to form the IVC can be identified, and the right common iliac vein is seen to be posterior to the left common iliac artery. In fact, all the pelvic veins are dorsal to the corresponding arteries.
Fig. 5.51
Veins of the posterior abdominal w a l l .
VEINS OF THE POSTERIOR ABDOMINAL WALL (Fig. 5.51) There is a rich venous anastomosis in the lumbar area between lumbar, sacral, intercostal veins and inferior vena cava, via segmental lumbar veins which drain directly into the cava and the ascending lumbar and azygos systems. This system usually has a connection with the left renal vein. The internal and external vertebral venous plexuses drain via segmental lumbar veins into the inferior vena cava. The lumbar veins are joined sequentially on both sides of the vertebral column by an ascending lumbar vein, which also extends inferiorly to the lateral sacral and iliolumbar veins. (The iliolumbar vein also drains into the common iliac vein.) The ascending lumbar vein ascends on the vertebral bodies at the root of the transverse processes deep to the psoas muscle and extends superiorly to the azygos system.
