Comparison of Non-Enhanced, Bolus Enhanced, and Delayed Scanning Techniques in Computed Tomography of Hepatic Tumours

Abstract

Non-enhanced, bolus contrast medium enhanced and 4 to 6 hours delayed computed tomography of the liver was performed in a prospcctivc study of 53 patients. Forty patients had focal lesions, in 12 of these they were hypervascular. Contrast medium was administered as an initial bolus followed by a rapid injection of meglumine metrizoate (Isopaque Cerebral). The total iodine dose varied between 56 and 63 g, which gave an average increase in attenuation of 14 HU in normal parenchyma comparing delayed with nonenhanced scanning. Presence and extent of focal lesions were evaluated in a randomized and independent analysis by two radiologists. The percentage of examinations with correct tumour description was higher with bolus scanning (observer I 73%. observer I1 75%) and delayed scanning (observer I 75%, observer I1 78%) than with non-enhanced scanning (observers I and I1 67%). An optimal bolus technique requires an exact timing of the contrast medium administration and scanning. Delayed scanning provides an excellent supplement when the bolus examination is suboptimal or shows equivocal findings.

Contrast enhancement of liver parenchyma and biliary tract related to liver function at delayed computed tomography

“…During an investigation of hepatic focal lesions at delayed CT we observed that many patients had contrast medium in the biliary tract (19). The examinations were reviewed in order to decide the extent and diagnostic value of biliary tract opacification.…”