Accuracy of Iodinated Contrast and Saline Delivery Using Piston-Driven and Peristaltic Power Injectors In CT
Abstract
Purpose
To assess the accurate delivery of iodinated contrast media (ICM) and saline flush volumes administered using piston-driven and peristaltic power injectors.
Methods
Seven clinically implemented injection protocols were executed using on both a piston-based injector and a peristaltic-based injector. The protocols represented patients from pediatric to bariatric populations, and incorporated variations in injection rate, contrast volume, saline volume, and contrast dilution. Reference ICM samples with accurately prepared iodine concentrations were scanned on a CT system (Discovery HD750, GE Healthcare) to generate a calibration relationship between CT attenuation and iodine concentration. For each injection, the saline test volume and the total volume of contrast plus saline flush were measured. To quantify the relative contributions of contrast and saline, the combined mixture was diluted to 10 mg I/mL and rescanned. Measured CT numbers were converted to iodine concentrations using the calibration curve, and the original mixture concentrations were used to back-calculate the actual delivered ICM and saline volumes. Percent deviations between programmed and measured volumes were determined, and statistical significance was evaluated using one-sample t-tests.
Results
For the peristaltic injector, ICM volume deviations ranged from 5.0% to 10.5%, while saline flush deviations ranged from 0.58% to 9.12%. In comparison, the piston-driven injector demonstrated ICM volume errors between 9.9% and 36%, with saline flush errors ranging from 1.5% to 51.7%. Across all protocols, the differences between prescribed and delivered volumes were statistically significant for both injector systems (p < 0.005).
Conclusion
Across most protocols, both injector types tended to administer higher-than-intended ICM volumes and lower-than-intended saline flush volumes. An exception was observed in pediatric protocols using the peristaltic injector, which delivered excess saline. These results underscore the need for routine quality assurance and injector performance validation to support reliable and reproducible contrast administration in clinical CT imaging.