CT of the abdomen: Degree and quality of enhancement obtained with two concentrations of the same iodinated contrast medium with fixed iodine delivery rate and total iodine load

Objectives: to compare vascular and parenchymal enhancement in abdominal computed tomography (CT) using two iodine concentrations (370 vs 300 mg I/mL) of the same contrast medium (CM) molecule (iopromide), using fixed iodine delivery rate (IDR, 1.2 g I/s) and total iodine load (630 mg I/kg). Methods: 144 patients were randomized into two groups: group A receiving iopromide 370 and group B receiving iopromide 300. Attenuation values (AV) were measured in correspondence to key anatomical structures on different phases and compared between groups with parametrical tests. Qualitative analysis was also performed. Peak injection pressure and local discomfort at the site of injection (pain and warmth) were registered. Results: mean AV of abdominal aorta in late arterial phase were 300.32 + 59.76 for group A and 298.2 +/- 59.14 for group B (p = 0.8); mean AV of portal vein in portal phase were 190.5 +/- 29.92 for group A and 192.91 +/- 24.12 for group B (p = 0.6). Mean AV of liver parenchyma in portal phase were 124.73 +/- 18.22 for group A and 125.11 +/- 15.7 for group B (p = 0.9); mean AV of liver at equilibrium were 85.11 +/- 7.75 for group A and 85.41 +/- 8.09 for group B (p = 0.8). Qualitative analysis did not show significant differences between groups (p > 0.05). Median peak injection pressure was lower in group B (93 psi, 76-172) than in group A (115 psi, 88-288, p < 0.0001), while discomfort at injection site was not significantly different (p > 0.05). Conclusions: with fixed IDR and total iodine load, comparable quantitative and qualitative enhancement can be achieved with different concentrations of the same CM. Peak injection pressure increases using CM with higher iodine concentration. (C) 2014 Elsevier Ireland Ltd. All rights reserved.