Radiology Residents’ Independent Diagnosis of Appendicitis Using 2-mSv Computed Tomography: A Secondary Analysis of a Large Pragmatic Randomized Trial

Abstract

Objective To compare the diagnostic performance and clinical outcomes of 2-mSv computed tomography (CT) and conventional-dose CT (CDCT), following radiology residents’ interpretation of CT examinations for suspected appendicitis. Materials and Methods Altogether, 3074 patients with suspected appendicitis aged 15–44 years (28 ± 9 years, 1672 females) from 20 hospitals were randomly assigned to the 2-mSv CT (n = 1535) or CDCT (n = 1539) groups in a pragmatic trial from December 2013 and August 2016. Overall, 107 radiology residents participated in the trial as readers in the form of daily practice after online training for 2-mSv CT. They made preliminary CT reports, which were later finalized by attending radiologists via addendum reports, for 640 and 657 patients in the 2-mSv CT and CDCT groups, respectively. We compared the diagnostic performance of the residents, discrepancies between preliminary and addendum reports, and clinical outcomes between the two groups. Results Patient characteristics were similar between the 640 and 657 patients. Residents’ diagnostic performance was not significantly different between the 2-mSv CT and CDCT groups, with a sensitivity of 96.0% and 97.1%, respectively (difference [95% confidence interval {CI}], -1.1% [-4.9%, 2.6%]; P = 0.69) and specificity of 93.2% and 93.1%, respectively (0.1% [-3.6%, 3.7%]; P > 0.99). The 2-mSv CT and CDCT groups did not significantly differ in discrepancies between the preliminary and addendum reports regarding the presence of appendicitis (3.3% vs. 5.2%; -1.9% [-4.2%, 0.4%]; P = 0.12) and alternative diagnosis (5.5% vs. 6.4%; -0.9% [-3.6%, 1.8%]; P = 0.56). The rates of perforated appendicitis (12.0% vs. 12.6%; -0.6% [-4.3%, 3.1%]; P = 0.81) and negative appendectomies (1.9% vs. 1.1%; 0.8% [-0.7%, 2.3%]; P = 0.33) were not significantly different between the two groups. Conclusion Diagnostic performance and clinical outcomes were not significantly different between the 2-mSv CT and CDCT groups following radiology residents’ CT readings for suspected appendicitis.

Observation Safely Reduces the Use of the Computerized Tomography in Medium-to-Low-Risk Patients with Suspected Acute Appendicitis: Results of a Randomized Controlled Trial

“…The present study showed a similarly low rate of normal CT scans in the CT and observation groups (37.5% vs. 34.5%, accordingly). If the diagnosis remains unclear after repeated ultrasound examinations (by two independent radiologists) and a CT scan is indicated, some authors suggest that low-dose CT may be an option since diagnostic accuracy and clinical results for suspected appendicitis did not differ between the 2-mSv CT and conventional-dose CT (CDCT) groups [ 25 ]. The OPTICAP study showed that the ability not only to diagnose acute appendicitis but also to differentiate between complicated and uncomplicated cases for individuals with a high risk of acute appendicitis was equally accurate with contrast-enhanced low-dose CT and normal CT [ 26 ].…”