About one third of delayed diagnoses are not recognized on subsequent radiologic exams due to multiple kinds of errors, according to a study published in the March issue of the American Journal of Roentgenology.

Though the amount of interpretation error in daily radiology practice is relatively small, the error rate is much higher in studies that do contain abnormalities. These issues become increasingly serious as the errors are perpetuated and diagnoses are delayed. Young W. Kim and Liem T. Mansfield, MD, of the Brooke Army Medical Center in San Antonio, Texas, and the Uniformed Services University of Health Sciences in Bethesda, Md., respectively, aimed to identify why delayed diagnoses in radiology are not recognized on subsequent radiologic examinations.

The retrospective study included 656 radiologic examinations with delayed diagnoses from July 2002 to January 2010. Two radiologists reviewed each case and then classified the diagnostic errors according to a modified scheme developed by the authors. More than one type of error was assigned to each case when applicable. Histologic diagnoses, CT, and MRI served as the reference standard.

A total of 1,269 errors were found out of the 656 exams. An average of 251 days elapsed from the initial interpretation error and the correct diagnosis, and a range of zero to 4,611 days was revealed from the data. The correct diagnoses were not recognized in subsequent exams in 30 percent of the 656 cases.

Forty-two percent of the errors were due to underreading and 22 percent were made when an additional, more clinically-significant abnormality was overlooked after the first but less important finding was identified. Nine percent of the errors caused by faulty interpretation and seven percent occurred when the finding was on the periphery of the location of interest. Five percent of the errors were attributed to lack of interpreter consultation with prior comparisons. Delayed diagnoses most often occurred in musculoskeletal sections.

“It is important to analyze and understand diagnostic errors in radiology so that steps can be implemented to decrease future mistakes,” wrote Kim and Mansfield.