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 CT were prospectively and randomly assigned to 1 of 2 groups. All patients received iopromide at 300 mg I/mL: group 1 at room temperature (~23°C [~73°F]) and group 2 prewarmed to body temperature (37°C [99°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; CM extravasations 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). Signal-to-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.