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

Influence of Contrast Media Temperature and Concentration on Patient Comfort and Safety in Computed Tomography: CATCHY II Trial

BACKGROUND

Previous research on the necessity to reduce the viscosity of contrast media (CM) by either prewarming CM before injection during computed tomography (CT) or by using less concentrated CM has yielded conflicting results. In addition, there is limited evidence on patient comfort.

OBJECTIVES

The aim of the study was to examine if prewarming CM, with varying CM concentrations, is superior to CM at room temperature, with respect to patient comfort and safety in CT.

MATERIALS AND METHODS

All elective patients scheduled for contrast-enhanced CT scans at Maastricht University Medical Center+ between October 27, 2021 and October 31, 2022 were eligible for inclusion when a questionnaire evaluating patient comfort was completed. This 1-year period was divided into 4 intervals (4 groups): group 1 (370 mg I/mL, 37°C), group 2 (370 mg I/mL, room temperature), group 3 (300 mg I/mL, 37°C), and group 4 (300 mg I/mL, room temperature). All CT scans were performed using state of the art equipment (Siemens Healthineers; SOMATOM Force and SOMATOM Definition AS, Forchheim, Germany). Contrast media injections were performed using a dual-head power injector (Stellant; Bayer Healthcare, Berlin, Germany) and individualized to body weight and/or tube voltage, depending on the CM protocols. After the CT scan, patients completed a questionnaire covering the primary outcomes comfort, pain, and adverse events such as feelings of heat, nausea, vomiting, itchiness, urticaria, difficulty breathing, dizziness, goosebumps, or an odd taste. Technicians were asked to report any adverse events, including extravasation and allergic-like reactions. The secondary outcome involved attenuation (in Hounsfield unit, HU), which was evaluated by assessing the HU of the coronary arteries for vascular CT, and liver enhancement in portal venous CT. The Kruskal-Wallis test was used for continuous scale outcomes and χ 2 tests for examining adverse events.

RESULTS

Results showed no significant differences examining comfort score ( P = 0.054), pain sensation ( P = 0.469), extravasation ( P = 0.542), or allergic-like reaction ( P = 0.253). Significant differences among the 4 groups were found with respect to heat sensation and dizziness ( P = 0.005 and P = 0.047, respectively), showing small effect sizes. All other adverse effects showed no significant results. No significant differences were observed in coronary attenuation among the 4 groups in coronary CT angiography ( P = 0.113). When analyzing attenuation in portal venous CT scans, significant differences were found among the 4 groups ( P = 0.008).

CONCLUSIONS

Administrating prewarmed CM is nonsuperior compared with CM at room temperature in relation to patient comfort and safety, regardless of CM concentration. These findings suggest that prewarming CM before usage is unnecessary, which will improve the efficiency of daily clinical workflow and brings environmentally friendly benefits.

The relationship between iodinated contrast material temperature and adverse reactions: A meta-analysis of 307,329 injections

OBJECTIVE

The effect of iodinated contrast material (CM) temperature on injection pressures and viscosity has been well established. However, the effect of extrinsic warming of CM on allergic reactions and extravasations remains unclear. The purpose of this study is to compare the rates of allergic reactions and extravasations between warmed CM to room temperature CM.

METHODS

We conducted a comprehensive systematic search using PubMed, Embase, and Web of Science databases for all studies that assess the impact of warmed CM on adverse reactions. The primary outcomes of our study were allergic reaction and extravasation rates. We calculated weighted pooled odds ratios (OR) and 95% confidence intervals (CI) for all outcomes using the random-effects model. A P-value <0.05 was considered statistically significant. We conducted subgroup analyses based on the viscosity of the CM.

RESULTS

A total of five studies, including 307,329 CM injections (86,676 at room temperature and 220,653 warmed to 37 °C), were included in the analysis. For high viscosity CM, pre-warming was associated with significantly lower allergic reaction rates (OR: 0.59, 95% CI: 0.49-0.72, P < 0.00001). There was no significant difference in rates of extravasation for high viscosity CM (OR: 0.53, 95% CI: 0.20-1.43, P = 0.21).

DISCUSSION

Our meta-analysis suggests that warming CM to 37 °C is a safe and effective approach to reduce the risk of allergic reactions and physiologic reactions during injection of high-viscosity CM. However, there was no significant difference in extravasation rates between warmed and room temperature CM, regardless of viscosity.

Patient Comfort in Modern Computed Tomography: What Really Counts

Background: The purpose of the present study is to evaluate the patient comfort during CT examinations with a modern CT scanner (Photon-Counting CT (PCCT)) and to compare the perceived patient comfort with a standard CT scanner. Methods: A total of 157 patients participated in this study and completed a questionnaire on their subjective perceptions after their CT examination. The following aspects of comfort were rated on a 5-point Likert scale: (1) claustrophobia in general and during the examination, (2) the effort to lie down and to get up from the CT table, (3) the speed and comfort of the CT table, (4) the difficulty of holding the breath during the CT scan, and (5) the communication during the examination. Results: Patients rated the modern CT scanner significantly better in terms of speed and comfort of the CT table and in terms of difficulty of holding their breath during the CT scan. The answers regarding the other aspects of comfort did not reveal significant differences. When asked for a comparison, patients who did perceive a difference between both scanners rated the modern CT scanner as more comfortable in all aspects of comfort. Conclusions: The survey did not reveal any major deficits in terms of comfort on the standard CT scanner. However, patients perceived the structural changes positively and appreciated the comfort of a modern CT scanner.