HEPATIC CT ENHANCEMENT - A METHOD TO DEMONSTRATE REPRODUCIBILITY

Optimal techniques for intravenous administration of contrast material in computed tomographic (CT) examination of the liver remain controve rsial mainly because of inaccurate methods of data evaluation. This st udy tested the reproducibility of hepatic contrast material enhancemen t within the same patient and the accuracy of two methods of data anal ysis. Fourteen patients received identical CT examinations. Attenuatio n of liver and vessels was measured before and after administration of contrast material, and enhancement was calculated for each image. Dat a were analyzed by averaging enhancement values obtained over 5- and 1 0-second intervals and by using a new computer program that creates an enhancement-time curve and measures area under the curve (AUC) for an y specific time interval. Data were compared between patients' first a nd second examinations. Mean liver enhancement was nearly identical at all time intervals with the AUC technique. Analysis of interpatient d ata showed marked variability of all parameters at all measured time i ntervals, suggesting that results from comparative studies within the same patient may be more accurate than those for studies of two differ ent treatment groups. The AUC technique is preferable to other methods of data analysis for contrast enhancement evaluation.