Secondary imaging for suspected appendicitis after equivocal ultrasound: time to disposition of MRI compared to CT.

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Date Published

2018 Apr

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<p><strong>PURPOSE: </strong>The purpose of this study was to compare MRI to CT as a secondary imaging modality for children age 5&nbsp;years and older with suspected appendicitis after an equivocal abdominal ultrasound in terms of (1) the time to ED disposition decision, (2) surgery consultation rate, and (3) imaging test accuracy.</p>

<p><strong>METHODS: </strong>We retrospectively studied children with suspected appendicitis and equivocal ultrasound results who underwent MR or CT as secondary imaging in a pediatric emergency department over two-consecutive 9-month periods. No oral or intravenous contrast was utilized for MRI. No sedation was utilized for any modality. Time of disposition is the time to admission or discharge order.</p>

<p><strong>RESULTS: </strong>Twenty-five patients underwent CT and 30 underwent MRI, with no significant difference in the median time from ultrasound to disposition between the CT (5.9&nbsp;h, IQR 4.5, 8.4) and the MRI (5.9&nbsp;h, IQR 4.6, 6.9) groups (p =&nbsp;0.65). Fifteen patients had appendicitis. Of the 40 negative or equivocal studies, surgery was consulted for 79% in the CT and 48% in the MRI group (odds ratio 4.12, 95% CI 1.02-16.67). Diagnostic accuracy was as follows: MRI: sensitivity of 90%, specificity of 97.1%, positive predictive value of 90%, and negative predictive value of 97.1%. Abdominal CT: sensitivity of 88%, specificity of 98.6%, positive predictive value of 95.7%, and negative predictive value of 95.8%.</p>

<p><strong>CONCLUSION: </strong>MRI is a feasible alternative to CT for secondary imaging in acute appendicitis for showing comparable ED throughput metrics and diagnostic accuracy, with added benefits of reduced radiation and avoidance of intravenous contrast.</p>



Alternate Title

Emerg Radiol




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