Uncertain Result of Abdominal Ultrasound Produced by Undertrained Operator Increase the CT in the Pediatric Emergency Department

Background: Children with abdominal pain are commonly evaluated with ultrasound to reduce radiation exposure in the pediatric emergency department (PED). However, ultrasound is highly operator-dependent, and the results are varied according to the level of the operator. Uncertain result by the undertrained operator may increase the CT, paradoxically.

Objective: To compare the correlation between the level of ultrasound operator and the presence of an uncertain conclusion which leads to additional CT scans.

Methods: This study was a retrospective cohort pilot study conducted at a tertiary academic PED. Patients under 18 years old with abdomen ultrasound from January to March 2017 were eligible, and chronic disorders including malignancy, hepatobiliary disease, and previous abdominal surgery history were excluded. Patients were classified into ‘Specialist’ group (SG) operated ultrasound by radiology specialist, and ‘Resident’ group (RG) by radiology resident. In our institution, radiology specialist operated ultrasound during the working day (Monday to Friday, 9 AM to 6 PM, except holiday), and after working hours, radiology resident operated. We compared the rate of uncertain ultrasound conclusions and additional CT between two groups using Chi-square or Fisher’s exact test.

Results: A total of 106 were analyzed. Mean age was 4.84 years, and 68 (64.2%) were boys. SG were 62 (58.5%), and RG were 44 (41.5%). 22 (20.8%) patients had an uncertain conclusion. Among them, SG were 5 (22.7%), and RG were 17 (77.3%). (p < 0.001). 7 patients underwent additional CT scans with an uncertain conclusion. Only 1(14.3%) patient in the SG and 6 (85.7%) in the RG. (p < 0.001)

Conclusions: Abdominal ultrasound operated after working hours by radiology residents had a more uncertain conclusion and led to more CT imaging. If the radiology specialist was available at a time other than working hours, unnecessary CT scans might be reduced by about 70%.