Increasing Neuroradiology Exam Volumes On-Call Do Not Result in Increased Major Discrepancies in Primary Reads Performed by Residents

Jared T Verdoorn, Christopher H Hunt*, Marianne T Luetmer, Christopher P Wood, Laurence J Eckel, Kara M Schwartz, Felix E Diehn , David F Kallmes
Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA

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© Verdoorn et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905 USA; Tel: 507-284-2097; Fax: 507-284-0348; E-mail:


Background and Purpose:

A common perception is that increased on-call workload leads to increased resident mistakes. To test this, we evaluated whether increased imaging volume has led to increased errors by residents.

Materials and Methods:

A retrospective review was made of all overnight neuroradiology CT exams with a primary resident read from 2006-2010. All studies were over-read by staff neuroradiologists next morning. As the volume is higher on Friday through Sunday nights, weekend studies were examined separately. Discrepancies were classified as either minor or major. “Major” discrepancy was defined as a discrepancy that the staff radiologist felt was significant enough to potentially affect patient care, necessitating a corrected report and phone contact with the ordering physician and documentation. The total number of major discrepancies was recorded by quarter. In addition, the total number of neuroradiology CT studies read overnight on-call was noted.


The mean number of cases per night during the weekday increased from 3.0 in 2006 to 5.2 in 2010 (p<0.001). During the weekend, the mean number of cases per night increased from 5.4 in 2006 to 7.6 in 2010 (p<0.001). Despite this increase, the major discrepancy rate decreased from 2.7% in 2006 to 2.3% in 2010 (p=0.34).


Despite an increase in neuroradiology exam volumes, there continues to be a low major discrepancy rate for primary resident interpretations. While continued surveillance of on-call volumes is crucial to the educational environment, concern of increased major errors should not be used as sole justification to limit autonomy.

Keywords: Discrepancy, education, error, on-call, resident..