Transfer patient imaging: discordances between community and subspecialist emergency radiologists

To determine the rate and nature of significant discordances between community and subspecialist emergency radiologists' interpretations of cross-sectional exams performed on patients transferred to our trauma center.

Outside hospital CT and MRI exams performed on transfer trauma patients are routinely overread by subspecialist emergency radiologists, specifying either concordance or discordance with the interpretation by the community radiologist. We evaluated the discordant reports for clinical significance, defined as an additional finding or difference in interpretation which was likely to affect patient management. The total rate of significant discordances, rate by modality, rate by body region, and rate per patient transferred were calculated. The most common errors were identified, and the distribution of errors among individual community radiologists was examined.

9175 exams were reviewed. Significant discordances were encountered in 4.1% of exams: 3.9% for CT and 6.7% for MRI; 5.1% for head and neck exams, 3.3% for spine, 3.8% for torso, and 2.9% for extremities. The discordance rate per patient transferred was 7.7%. The most common discordances involved missing injuries to the cranio-cervical junction, missing or misinterpreting vascular injuries in the neck, and incompletely characterizing facial fractures. Discordances were evenly spread among 220 community radiologists.

There is frequent discordance between community and emergency radiologists' interpretations of CT and MRI exams, leading to a change in transferred patient management. Thus, trauma center radiologists provide added value overreading these patients' exams. It is difficult to predict which patients or exams will contain discordances, justifying routine overreading of all such exams.