Bacterial contamination of automated MRI contrast injectors in clinical routine.

To quantify the frequency of bacterial contamination of the injected contrast agent/saline solution by an automated contrast injection system, and to evaluate whether usage of a novel tube system can reduce it. For bacterial contamination quantification two identical automated piston pump MRI contrast injectors were used in combination with a standard tube system. 3-5 ml of the contrast agent/saline solution was collected from the system prior to its connection to the patients' venous cannula in 104 consecutive patients. To test, whether a novel tube system reduces contamination, a tube system with shielded screw connections was used with the same contrast injectors and contrast agent/saline samples were collected in further 101 patients. Specimens were microbiologically analyzed. Frequencies of contamination were compared using Fisher exact test. With the standard tube system, bacterial contamination was observed in 5.8% (6 out of 104 specimens). With the novel tube system, contamination was observed in 2.0% (2 out of 101 specimens, p=0.280). was the most common germ (5 cases) followed by (2 cases) and (1 case). Bacterial contaminations of MRI contrast injectors occurred in a non-negligible frequency especially with . A trend towards reduced bacterial contamination was seen when a novel tube system with shielded screw connections was used.