Abstract
Background
Recent studies suggest potentially improved inter-patient variability in hepatic enhancement by dosing contrast media (CM) according to lean body weight (LBW); however, studies vary in dosing strategy and most involved solely Japanese patients.
Purpose
To compare the magnitude and inter-patient variability in mean hepatic enhancement (MHE) when dosing CM according to total body weight (TBW) versus LBW in a Western population.
Material and Methods
With ethics approval, this study comprised two parts: (i) 100 CTs acquired with 1.3 mL Isovue 370/kg TBW were analyzed; (ii) 108 patients were consented for LBW dosing at 1.9 mL/kg (max. 150 mL, both groups). Liver attenuations were obtained from regions of interest. The MHE, MHE per gram of iodine (MHE/I), and adjusted MHE (aMHE = MHE/(I/TBW or LBW)) were calculated. We compared patient populations (Fisher’s exact test, t-tests) and inter-patient variability (F-tests of variances in MHE) and performed linear regressions of MHE and aMHE.
Results
Cohorts were similar in age, sex, TBW, LBW, and total CM dose. MHE was higher in part 2 (63.1 ± 13 vs. 56.3 ± 12 HU, P = 0.0001) but variances were similar (P > 0.7). In part 2, men received more CM (P = 0.0002) and MHE was higher (P = 0.0002); women received less CM (P = 0.053) but showed a non-significant trend for greater MHE (P = 0.07). MHE/I was higher for women in part 2 (P = 0.01) and stable in men (P = 0.72). Linear regressions showed no lines of best-fit with non-zero slopes, for both sexes and study parts.
Conclusion
With CM dose constant, LBW dosing yielded a higher magnitude in MHE but did not reduce inter-patient variability.
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