Minor vascular anatomy of the abdomen and pelvis: a CT atlas.

With the early generations of computed tomographic (CT) scanners, interpretation of abdominal and pelvic scans focused on the solid organs, hollow viscera, and retroperitoneum. Attention to blood vessels generally was given only to the aorta and inferior vena cava and their larger branches. The newer generations of scanners allow rapid acquisition of high-resolution images during the vascular phase of mechanical bolus injection of intravenous contrast material. Visualization of second-order vascular branches has thus become routine. Recent improvements in software allow real-time reconstruction of data in multiple planes, which enables demonstration of long segments of vessels within a single image. Approximately 7,000 abdominal and pelvic CT scans were reviewed with attention to vascular detail. Cases are presented that illustrate peripancreatic, perigastric, parietal, and hypogastric vessels; fetal remnants and structures that may be mistaken for vessels; and collateral pathways of both arterial and venous flow. With increasing use of helical CT scanning, smaller vessels can be identified with greater confidence. Knowledge of normal CT vascular anatomy facilitates understanding of collateral pathways when vessel engorgement is perceived.