Discrepancy rates of on-call radiology residents' interpretations of CT angiography studies of the neck and circle of Willis.

Objective: The purpose of our study was to determine the discrepancy rates of radiology residents' interpretations of emergent CT angiography (CTA) studies of the neck and circle of Willis and to assess any adverse clinical outcomes.

Materials And Methods: Five hundred thirty-eight CTA studies (287 circle of Willis and 251 neck) ordered emergently after hours and given preliminary readings by radiology residents from January 1, 2006, through December 31, 2007, were retrospectively reviewed. Discrepancies between the interpretations of radiology residents and the final reports of neuroradiology attending physicians were classified as either false-negatives (failure to recognize abnormalities) or false-positives (misinterpreting normal scans as abnormal). Discrepancies that could affect patient care or clinical care were considered major.

Results: Overall, the discrepancy rate was 13.6% for circle of Willis CTA and 13.5% for neck CTA. The misinterpretation rate of first-year residents was 19.5%, which was statistically significant compared with more senior-level residents (p = 0.05). There were 57 false-negative interpretations. The most common misses were stenosis greater than 50% (n = 16) and aneurysm (n = 15), and the most common false-positive was overcalling a potential intracranial aneurysm (n = 7). No adverse clinical outcomes were detected.

Conclusion: The discrepancy rate between interpretations by on-call radiology residents and attending physicians of neuroradiology CTA studies was higher than expected at 13.6%, with a statistically significant greater miss rate among the most junior residents, which may be mitigated by recent changes with respect to the radiology residents' overnight call. No adverse clinical outcome was detected.