Influence of Contrast Material Temperature on Patient Comfort and Image Quality in Computed Tomography of the Abdomen A Randomized Controlled Trial

Background: International guideline recommendations on safe use of contrast media (CM) are conflicting regarding the necessity to prewarm iodinated CM. Purpose: Aim of the study was to evaluate the effects of room temperature CM compared with prewarmed CM on image quality, safety, and patient comfort in abdominal computed tomography (CT). Methods: CATCHY (Contrast Media Temperature and Patient Comfort in Computed Tomography of the Abdomen) is a double-blinded, randomized noninferiority trial. Between February and August 2020, 218 participants referred for portal venous abdominal CTwere prospectively and randomly assigned to 1 of 2 groups. All patients received iopromide at 300 mg I/mL: group 1 at room temperature (similar to 23 degrees C [similar to 73 degrees F]) and group 2 prewarmed to body temperature (37 degrees C [99 degrees F]). A state-of-the-art individualized CM injection protocol was used, based on body weight and adapted to tube voltage. Primary outcome was absolute difference in mean liver attenuation between groups, calculated with a 2-sided 95% confidence interval. The noninferiority margin was set at -10 HU. Secondary outcomes were objective (signal-to-noise ratio and contrast-to-noise ratio) and subjective image quality; CMextravasations and other adverse events; and participant comfort (5-point scale questionnaire) and pain (numeric rating scale). This trial is registered with ClinicalTrials.gov (NCT04249479). Results: The absolute difference in mean attenuation between groups was + 4.23 HU (95% confidence interval, +0.35 to +8.11; mean attenuation, 122.2 +/- 13.1 HU in group 1, 118.0 +/- 15.9 HU in group 2; P = 0.03). Signalto-noise ratio, contrast-to-noise ratio, and subjective image quality were not significantly different between groups (P = 0.53, 0.23, and 0.99 respectively). Contrast extravasation occurred in 1 patient (group 2), and no other adverse events occurred. Comfort scores were significantly higher in group 1 than in group 2 (P = 0.03); pain did not significantly differ (perceived P > 0.99; intensity P = 0.20). Conclusions: Not prewarming iodinated CM was found noninferior in abdominal CT imaging. Prewarming conferred no beneficial effect on image quality, safety, and comfort, and might therefore no longer be considered a prerequisite in state-of-the art injection protocols for parenchymal imaging.