Immediate hypersensitivity reactions to IV non-ionic iodinated contrast in computed tomography

Area of Science:

• Radiology
• Medical Imaging
• Pharmacovigilance

Background:

• Computed tomography (CT) frequently uses intravenous contrast media for enhanced visualization.
• Non-ionic iodinated contrast agents are standard, but rare hypersensitivity reactions remain a concern.
• The increasing volume of CT examinations necessitates understanding contrast reaction risks.

Purpose of the Study:

• To determine the incidence and severity of immediate hypersensitivity reactions to intravenous non-ionic iodinated contrast during CT.
• To identify significant risk factors associated with these contrast reactions.

Main Methods:

• A retrospective analysis of patients experiencing immediate hypersensitivity reactions during CT with iopromide contrast at an Australian tertiary hospital.
• Comparison of reaction data with all contrast CTs over a four-year period.
• Statistical analysis using chi-square and odds ratios for variables including age, gender, referral source, and season.

Main Results:

• The incidence of immediate hypersensitivity reactions was 0.16% (47 of 29,962 patients).
• Reactions were predominantly mild (70%), with moderate (23%) and severe (7%) reactions also recorded.
• Significant risk factors identified include female gender (OR 2.41), age under 55 (OR 2.46), outpatient status (OR 5.42), and CTs performed in spring/autumn (OR 2.77).

Conclusions:

• Immediate hypersensitivity reactions to non-ionic iodinated contrast in CT are infrequent and generally mild.
• Risk factors such as female gender, younger age, outpatient status, and seasonal variations (spring/autumn) are associated with increased reaction risk.
• This study highlights a novel observation of seasonal variation in contrast reaction incidence.