SPIRAL CT DURING ARTERIAL PORTOGRAPHY - TECHNIQUE AND APPLICATIONS

Spiral computed tomography during arterial portography (CTAP) combines rapid scanning with selective imaging during the portal phase of enha ncement of the liver, resulting in an effective method for evaluation of liver neoplasms prior to partial hepatic resection, Compared with d ynamic incremental CTAP, spiral CTAP results in improved quality of th ree-dimensional and multiplanar reconstructions, facilitating presurgi cal planning. Accurate volumetric analysis of the tumor can be perform ed, and subsegmental tumor localization is facilitated by the high lev els of hepatic and portal venous enhancement, Additional advantages of spiral CTAP include small reconstruction intervals for improved lesio n detection, However, the specificity of spiral CTAP is low because bo th benign and malignant tumors appear as hypoattenuating perfusion def ects. In addition, both focal and geographic nontumorous perfusion def ects may be seen more frequently with spiral CTAP than with dynamic CT AP. Knowledge of common diagnostic pitfalls is necessary for accurate interpretation of spiral CTAP images.