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Abdominal fellowship-trained versus generalist radiologist accuracy when interpreting MR and CT for the diagnosis of appendicitis

A Correction to this article was published on 26 August 2021

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To compare the diagnostic accuracy of generalist radiologists working in a community setting against abdominal radiologists working in an academic setting for the interpretation of MR when diagnosing acute appendicitis among emergency department patients.


This observational study examined MR image interpretation (non-contrast MR with diffusion-weighted imaging and intravenous contrast-enhanced MR) from a prospectively enrolled cohort at an academic hospital over 18 months. Eligible patients had an abdominopelvic CT ordered to evaluate for appendicitis and were > 11 years old. The reference standard was a combination of surgery and pathology results, phone follow-up, and chart review. Six radiologists blinded to clinical information, three each from community and academic practices, independently interpreted MR and CT images in random order. We calculated test characteristics for both individual and group (consensus) diagnostic accuracy then performed Chi-square tests to identify any differences between the subgroups.


Analysis included 198 patients (114 women) with a mean age of 31.6 years and an appendicitis prevalence of 32.3%. For generalist radiologists, the sensitivity and specificity (95% confidence interval) were 93.8% (84.6–98.0%) and 88.8% (82.2–93.2%) for MR and 96.9% (88.7–99.8%) and 91.8% (85.8–95.5%) for CT. For fellowship-trained radiologists, the sensitivity and specificity were 96.9% (88.2–99.5%) and 89.6% (82.8–94%) for MR and 98.4% (90.5–99.9%) and 93.3% (87.3–96.7%) for CT. No statistically significant differences were detected between radiologist groups (p = 1.0, p = 0.53, respectively) or when comparing MR to CT (p = 0.21, p = 0.17, respectively).


MR is a reliable, radiation-free imaging alternative to CT for the evaluation of appendicitis in community-based generalist radiology practices.

Key Points

There was no significant difference in MR image interpretation accuracy between generalist and abdominal fellowship-trained radiologists when evaluating sensitivity (p = 1.0) and specificity (p = 0.53).

There was no significant difference in accuracy comparing MR to CT imaging for diagnosing appendicitis for either sensitivity (p = 0.21) or specificity (p = 0.17).

With experience, generalist radiologists enhanced their MR interpretation accuracy as demonstrated by improved interpretation sensitivity (OR 2.89 CI 1.44-5.77, p = 0.003) and decreased mean interpretation time (5 to 3.89 min).

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Fig. 4

Change history



Area under the receiver operator characteristic curve


Full magnetic resonance protocol including enhanced, unenhanced, and diffusion-weighted imaging


Confidence interval


Computed tomography


Diffusion-weighted imaging

ED :

Emergency department


Protocol limited to unenhanced magnetic resonance and diffusion-weighted imaging


Odds ratio


Standard deviation


Ultrasonography or ultrasound


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We would like to thank the University of Wisconsin – Madison Department or Radiology for use of their Picture Archiving and Communications System as well as the BerbeeWalsh Department of Emergency Medicine for their assist


This study has received funding by the National Institute for Diabetes and Digestive and Kidney Disease as well as the National Center for Advancing Translational Sciences.

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Correspondence to Michael D. Repplinger.

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The scientific guarantor of this publication is Dr. Michael Repplinger.

Conflict of interest

The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.

Statistics and biometry

One of the authors has significant statistical expertise.

Informed consent

Written informed consent was obtained from all subjects (patients) in this study.

Ethical approval

Institutional Review Board approval was obtained.

Study subjects or cohorts overlap

Some study subjects or cohorts have been previously reported in Radiology.2018;288(2):467–475. The current study is a re-interpretation of the image sets first acquired in the parent study, this time by three community-based generalist radiologists.


• Prospective

• Diagnostic or prognostic study

• Performed at one institution

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The original online version of this article was revised: The spelling of Newrhee Kim’s name was incorrect and the middle name in Perry J. Pickhardt’s name was missing.

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Bracken, R.L., Harringa, J.B., Markhardt, B.K. et al. Abdominal fellowship-trained versus generalist radiologist accuracy when interpreting MR and CT for the diagnosis of appendicitis. Eur Radiol 32, 533–541 (2022).

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  • Magnetic resonance imaging
  • Tomography, X-ray computed
  • Appendicitis