Effect of Fixed-Volume and Weight-Based Dosing Regimens on the Cost and Volume of Administered Iodinated Contrast Material at Abdominal CT

Purpose: To determine the magnitude of subject-level and population-level cost savings that could be realized by moving from fixed-volume low-osmolality iodinated contrast material administration to an effective weight-based dosing regimen for contrast-enhanced abdominopelvic CT.

Methods: HIPAA-compliant, institutional review board-exempt retrospective cohort study of 6,737 subjects undergoing contrast-enhanced abdominopelvic CT from 2014 to 2015. Subject height, weight, lean body weight (LBW), and body surface area (BSA) were determined. Twenty-six volume- and weight-based dosing strategies with literature support were compared with a fixed-volume strategy used at the study institution: 125 mL 300 mgI/mL for routine CT, 125 mL 370 mgI/mL for multiphasic CT (single-energy, 120 kVp). The predicted population- and subject-level effects on cost and contrast material utilization were calculated for each strategy and sensitivity analyses were performed.

Results: Most subjects underwent routine CT (91% [6,127/6,737]). Converting to lesser-volume higher-concentration contrast material had the greatest effect on cost; a fixed-volume 100 mL 370 mgI/mL strategy resulted in $132,577 in population-level savings with preserved iodine dose at routine CT (37,500 versus 37,000 mgI). All weight-based iodine-content dosing strategies (mgI/kg) with the same maximum contrast material volume (125 mL) were predicted to contribute mean savings compared with the existing fixed-volume algorithm ($4,053-$116,076/strategy in the overall study population, $1-$17/strategy per patient). Similar trends were observed in all sensitivity analyses.

Conclusions: Large cost and material savings can be realized at abdominopelvic CT by adopting a weight-based dosing strategy and lowering the maximum volume of administered contrast material.