Efficacy of Pamiray(R) as a Nonionic Intravenous Contrast Material: Experimental Study Using Normal Rabbits

ABSTRACT

PURPOSE: To evaluate the efficacy of Pamiray(R) as an intravenous nonionic contrast material by comparing it with an established nonionic contrast material (Iopamiro(R)). MATERIALS AND METHODS: Forty adult New Zealand white rabbits weighing about 3.0 kg were used in this study. Aortography and urography (scout, 5, 15 and 30 minutes delay after injection) were performed in ten rabbits with Pamiray(R) (370 mgI/mL) and in other ten rabbits with Iopamiro(R) (370 mgI/mL). All twenty rabbits under-went abdominal triple-phase spiral CT before and 5 and 30 seconds after injection of the contrast material. The degree of contrast enhancement seen on aortograms and intravenous urograms was determined using a three-point scale by two radiologists, who reached a consensus. CT attenuation expressed in Hounsfield units (HU) was measured using the regions of interest (ROIs) facility in the liver, bilateral kidneys, aorta, portal vein, and inferior vena cava. The Mann-Whitney U test was used in image evaluation for intergroup comparisons. RESULTS: There was no significant difference between the two groups in the degree of contrast enhancement seen on aortograns. In urography, however, Iopamiro(R) was superior to Pamiray(R) in demonstrating calyces of the right kidney on 15-minute delay images and Pamiray(R) was superior to Iopamiro(R) in demonstrating the right ureter and the renal pelvis on five minute-delay images and the left ureter on 30 minutes delay (p<.05). Peak enhancement of the aorta during the first phase of bdominal CT was higher in the group in which Pamiray(R) was used. CONCLUSION: When normal rabbits were used for aortography, abdominal CT, and urography, Pamiray(R), provided more effective contrast enhancement than a previously used nonionic contrast material, namely Iopamiro(R). There were, however, slight differences in the enhancement features of renal calyces and ureters seen on 5-and 15-minute urograms.