The non-diagnostic ultrasound in appendicitis: is a non-visualized appendix the same as a negative study?

Area of Science:

• Pediatric Radiology
• Emergency Medicine
• Abdominal Imaging

Background:

• Appendicitis is a common surgical emergency in children.
• Ultrasound (US) is frequently used for initial evaluation, but non-diagnostic exams are common.
• Determining the significance of non-diagnostic US is crucial for appropriate patient management.

Purpose of the Study:

• To evaluate outcomes in pediatric patients with non-diagnostic ultrasounds for appendicitis.
• To identify predictors of a negative diagnosis in this cohort.

Main Methods:

• Retrospective chart review of pediatric patients (0-18 years) undergoing abdominal US for appendicitis (2004-2013).
• Categorization of exams into non-diagnostic and non-visualized appendix groups.
• Analysis of clinical data and outcomes, including negative predictive value (NPV).

Main Results:

• 63.34% of 1383 US exams were non-diagnostic, primarily due to non-visualized appendix (777 cases).
• NPV for non-diagnostic and non-visualized exams were 84.47% and 86.36%, respectively.
• NPV significantly increased in patients with low white blood cell (WBC) counts (<7.5×10(9)/L: 97.12% and 98.86%; <11.0×10(9)/L: 95.59% and 96.99%).

Conclusions:

• Non-diagnostic ultrasounds in children with normal or mildly elevated WBC counts have a high negative predictive value.
• These findings support potentially avoiding further imaging in select pediatric appendicitis workups.
• This strategy may reduce radiation exposure and healthcare costs.