Liver CT: a practical approach to dynamic contrast enhancement.

The aim of this study was to establish a practical, simple protocol that reliably produces high quality dynamic incremental computed tomography (CT) of the liver. We reviewed 90 patients randomly allocated into six different protocols. All had preliminary unenhanced scans followed by a dynamic incremental CT of the liver. An initial delay of 30 seconds was used from the commencement of the injection of Iopamiro 370. The groups were: 1. Pump infusion (a) 100 mls at 2 mls/sec scanning inferosuperiorly. (b) 100 mls at 2 mls/sec scanning superoinferiorly. (c) 100 mls at 1 ml/sec scanning inferosuperiorly. (d) 50 mls at 1 ml/sec scanning inferosuperiorly. 2. 40 mls hand injected bolus followed immediately by 60 ml pump infusion at 1.3 mls/sec scanning inferosuperiorly. 3. 50 mls hand injected bolus scanning inferosuperiorly. The parameters recorded were the degree of hepatic parenchymal and hepatic venous enhancement and the aortic--IVC difference at the last slice through the liver, all measured in Hounsfield units. The protocols using 100 mls of contrast produced approximately twice the parenchymal and hepatic venous enhancement compared with those using 50 mls. Approximately 60-90% of examinations using 100 mls produced scans through the entire liver during the bolus or nonequilibrium phase, deemed the most sensitive for the detection of focal lesions, compared with 13-33% of those using 50 mls. Equally satisfactory results were obtained using the relatively inexpensive Biotel power injector preceded by a 40 ml hand injected bolus, compared with using an Angiomat angiography infusion pump.(ABSTRACT TRUNCATED AT 250 WORDS)