Objective: To compare the magnitude and inter-patient variability in mean hepatic enhancement (MHE) when dosing CM according to total body weight (TBW) vs lean body weight (LBW).


Materials and Methods: This prospective, single-center randomized controlled study evaluated hepatic enhancement of outpatient CTs acquired in the portal venous phase using a 35-second fixed injection duration of Omnipaque 350. Patients with chronic kidney, liver or heart disease were excluded. Patients were stratified by sex and randomized to either TBW-dosing (51 women and 60 men, 1.22 mL/kg) or LBW-dosing (59 men, 1.52 mL/kg LBW; 59 women, 1.67 mL/kg LBW). Liver attenuations were obtained from regions of interest. The MHE, MHE per gram of iodine (MHE/I) and adjusted MHE (aMHE=MHE/(I/TBW)) values and standard deviations were compared (unpaired t-tests and F tests).


Results: Cohorts were similar in age, sex, TBW and LBW. TBW groups received more contrast than LBW groups: men, 106.5±20 vs. 98.4±11 mL, p=0.007; women, 93.7±20 vs. 77.5±11 mL, p<0.0001). MHE was greater in the TBW groups, but was not statistically significant in men: men, 54.8±11 vs. 51.5±10 HU, p=0.087; women, 54.6±11 vs. 49.4±14, p=0.0248. There was no statistically significant difference in MHE/I or aMHE for men or women (p>0.05). The variances in MHE, MHE/I and aMHE were also not significantly different across all groups (p>0.05).

Conclusion: Using overall less contrast media dose, LBW dosing yielded similar MHE in men but not women. The yield of hepatic enhancement per gram of iodine was similar regardless of dosing technique.

Dosing iodinated contrast media according to lean vs. total body weight at abdominal CT: A stratified randomized controlled trial