Learning from past mistakes can reduce error rate

Trainee radiologists can benefit by studying the mistakes of their predecessors and focusing on clinical situations and radiographic findings that are often misdiagnosed.

Radiologists at University of Pittsburgh Medical Center conducted a comprehensive study of the errors made by on-call residents during their preliminary diagnosis. They presented their research as a scientific poster during the RSNA meeting. It was performed at a large academic medical center that includes a Level 1 trauma unit and 19 specialty and community hospitals and carries out 1.4 million examinations per year.

The authors, led by Dr. Barton F. Branstetter IV, reviewed 3194 discrepancies that occurred in 612,890 cases, representing an error rate of 0.52%. They categorized them by body part and type of diagnostic error. Only four cases had inadequate information.

In neuroradiology, there were 348 errors out of 99,695 examinations, and the error rate was 0.35%. The most common mistakes:

• missed or undercalled stroke (78 cases, 22% of mistakes)

• hemorrhage (51, 15%)

• neck/airway lesion (47, 14%)

• facial fracture (40, 11%)

"To avoid cases of missed Chiari 1 malformation, you must evaluate all images. Pathology is most easily identified on axial FLAIR images, but images in other planes, and with other pulse sequences, also need adequate attention," the authors wrote. "A right subdural hematoma may be missed without appropriate windowing, as when using narrow brain windows."

In abdominal imaging, there were 497 mistakes out of 116,851 procedures, and the error rate was 0.43%. The most frequent errors:

• missed or undercalled leak or inflammation (122 instances, 25% of mistakes)

• obstruction (76, 15%)

• abdominal trauma (53, 11%)

• solid visceral mass (41, 8%)

• urinary calculus (38, 8%)

In suspected cases of small bowel obstruction, the authors advised examiners to be aware of associated findings and alternate presentations of pathology. Air in the abdomen does not always mean an obstruction. Configuration and distribution are key aspects of the diagnosis.

"Small bowel obstruction can present in multiple ways. Dilated air-filled loops or loops with air fluid levels may not always be visible," they said.

In thoracic radiology, there were 1113 errors out of 179,373 examinations, and the error rate was 0.62%. The most common mistakes:

• missed pneumonia (315 instances, 28% of errors)

• overcalled pneumonia (214, 19%)

• missed or undercalled congestive heart failure or effusion (145, 13%)

• missed or undercalled lung mass (96, 9%)

It is fairly easy to miss retrocardiac masses, and they warrant extra attention, according to the authors, who recommended increased awareness of anatomic areas that are difficult to evaluate. Also relatively common are cases of pleural effusion correctly called but with missed necrotizing pneumonia. The authors suggested consultation with the on-call subspecialist.

In musculoskeletal, 1232 mistakes occurred in 216,971 examinations, representing an error rate of 0.57%. The most frequent errors:

• missed or undercalled fracture (631 instances, 51% of mistakes)

• overcalled fracture (210, 17%)

• missed or undercalled joint or soft-tissue injury (127, 10%)

"An electronic preliminary report generator is a useful tool for quality control in the emergency department. It may also serve as a teaching tool for trainees and as a source of material for missed case conferences and digital teaching files," the authors said.