Purpose: To assess the patient care benefit of a recently implemented institutional policy requiring official second-opinion consultation for all studies performed outside the institution.
Materials and methods: The institutional review board approved the retrospective review of patient data for this HIPAA-compliant study and waived the need for individual informed consent. The second-opinion consultation reports for outside neuroradiology studies finalized by subspecialty-trained neuroradiologists within calendar year 2008 were compared with the outside reports provided with the images. The reports were categorized by using a five-point scale: 1 indicated no difference in interpretation; 2, clinically unimportant difference in detection; 3, clinically unimportant difference in interpretation; 4, clinically important difference in detection; and 5, clinically important difference in interpretation. Clinically important differences were defined as those likely to change patient care or diagnoses. Statistical comparisons were performed by using two-sample continuity-corrected Z tests with two-sided alternatives. Bonferroni corrections were performed when more than two rates were compared. Confidence intervals for all rates were constructed by using the score interval along with the Yates continuity correction.
Results: Of 7465 studies, 4534 (60.7%) had an outside report for comparison. There were 347 (7.7%) instances with clinically important differences. Of these 347 discrepancies, 233 (67.1%) were category 4 and 114 (32.9%) were category 5. When the final diagnosis was determined from pathology reports, clinical assessments, and/or imaging follow-up, the second-opinion consultation was noted to be correct in 163 (84.0%) of 194 studies with category 4 or 5 discrepancies.
Conclusion: A 7.7% rate of discrepant interpretations (347 of 4534 studies) was noted for a service offering second-opinion consultations for outside examinations. Most were discrepancies in detecting abnormalities rather than in interpreting identified findings. When a definitive diagnosis was obtainable, the second-opinion consultation was more accurate in 84% of studies. Review of outside studies benefits patient care.