Veterinary radiologic error rate as determined by necropsy.

A large-scale postmortem auditing of antemortem imaging diagnoses has yet to be accomplished in veterinary medicine. For this retrospective, observational, single-center, diagnostic accuracy study, necropsy reports for patients of The Schwarzman Animal Medical Center were collected over a 1-year period. Each necropsy diagnosis was determined to be either correctly diagnosed or discrepant with its corresponding antemortem diagnostic imaging, and discrepancies were categorized. The radiologic error rate was calculated to include only clinically significant missed diagnoses (lesion was not reported but was retrospectively visible on the image) and misinterpretations (lesion was noted but was incorrectly diagnosed). Nonerror discrepancies, such as temporal indeterminacy, microscopic limitations, sensitivity limitations, and study-type limitations were not included in the error rate. A total of 1099 necropsy diagnoses had corresponding antemortem imaging; 440 diagnoses were classified as major diagnoses, of which 176 were discrepant, for a major discrepancy rate of 40%, similar to reports in people. Seventeen major discrepancies were diagnoses that were missed or misinterpreted by the radiologist, for a calculated radiologic error rate of 4.6%, comparable with error rates of 3%-5% reported in people. From 2020 to 2021, nearly half of all clinically significant abnormalities noted at necropsy went undetected by antemortem imaging, though most discrepancies owed to factors other than radiologic error. Identifying common patterns of misdiagnosis and discrepancy will help radiologists refine their analysis of imaging studies to potentially reduce interpretive error.