Design: Single-centre retrospective cohort
Population: 617,531 contrast-enhanced CT and MRI examinations over five years
Primary outcome: Direct costs and departmental delay from acute contrast reactions
Effect: Median added time 25 min (CT) and 27 min (MRI); median cost $15 (CT) and $1.66 (MRI)

This single-centre review covered five years of contrast-enhanced CT (363,671 examinations) and MRI (253,860) at a US institution. It identified 1099 acute reactions to iodinated contrast and 521 to gadolinium, classified by ACR severity criteria.

Most reactions needed no billable treatment: 29% after CT and 21% after MRI received a drug or procedure. Median direct costs were small, about $15 for CT and under $2 for MRI reactions, but rose steeply with severity, to over $13,900 for an admitted patient and up to about $238,000 for the most severe reaction. Reactions added a median of 25 minutes (IQR 11 to 43) for CT and 27 minutes (8 to 59) for MRI to time in the department.

For departments, the main operational cost is time and staff attention rather than drugs. Cost figures are US-specific and will not transfer to Indian hospitals, but the time burden and the severity gradient will. It supports keeping reaction kits, protocols and trained staff ready on every list rather than relying on premedication alone.

Keep a stocked reaction kit and a written treatment protocol in every contrast-enhanced CT and MRI room.
Train radiographers and nurses to recognise and grade reactions using standard severity criteria.
Build slack into contrast lists to absorb the time a reaction takes.
Record each reaction's type and severity in the patient record to guide future imaging.

Why it matters

Departments rarely count the time lost to contrast reactions, which affects every patient waiting behind the one who reacted.

The statistics, in plain English

The median cost is low because most reactions are mild. The very high maximum comes from a small number of severe reactions or admissions, which skews the average. Costs were estimated from US price databases, not measured bills.