What is the efficacy of ultrasound in detecting appendicitis in pediatric patients?

From the Guidelines

Ultrasound is highly effective for detecting appendicitis in pediatric patients, with a median sensitivity of 0.99 and median specificity of 0.96, and should be considered the first-line imaging modality for suspected appendicitis in children. The use of ultrasound in pediatric patients has been shown to be accurate and safe in terms of perforation rates, emergency department re-visits, and negative appendectomy rates 1. The procedure involves using a high-frequency linear transducer to visualize the appendix, with findings such as appendiceal diameter >6mm, wall thickening, non-compressibility, and surrounding inflammatory changes suggesting appendicitis.

Some key points to consider when using ultrasound for detecting appendicitis in pediatric patients include:

• The importance of operator experience and skill in performing the ultrasound examination
• The potential difficulties in visualizing the appendix in obese patients or when the appendix is retrocecal or obscured by bowel gas
• The value of having a full bladder during the examination to improve visualization of the appendix
• The potential need for additional imaging with MRI or low-dose CT if ultrasound results are equivocal but clinical suspicion remains high

The most recent and highest quality study, published in 2024, provides strong evidence for the use of ultrasound as the first-line imaging modality for suspected appendicitis in children, with a median sensitivity of 0.99 and median specificity of 0.96 1. This study supports the use of ultrasound as a highly effective and safe imaging modality for detecting appendicitis in pediatric patients, and recommends its use as the initial imaging study of choice for the diagnosis of acute appendicitis in pediatric and young adult patients.

From the Research

Efficacy of Ultrasound in Detecting Appendicitis in Pediatric Patients

• The efficacy of ultrasound in detecting appendicitis in pediatric patients has been studied in several research papers 2, 3, 4, 5, 6.
• According to a study published in 2017, ultrasound is currently the recommended initial imaging study of choice for the diagnosis of appendicitis in pediatric and young adult patients, despite its significant shortcomings, such as being time-intensive and operator-dependent 2.
• A systematic review and meta-analysis published in 2024 found that ultrasound exhibited higher specificity than sensitivity in diagnosing complicated appendicitis in pediatric patients, with sensitivities ranging from 33.9% to 51.5% and specificities ranging from 68.8% to 95% 3.
• Another study published in 2019 noted that ultrasound has become a routine imaging modality for diagnosing pediatric appendicitis, with magnetic resonance imaging (MRI) being considered as a potential alternative or secondary diagnostic modality in equivocal cases 4.
• A review published in 2016 recommended using ultrasound as the first-line imaging modality for diagnosing acute appendicitis, due to its excellent specificity in both pediatric and adult patient populations, despite its limited sensitivity 5.
• A meta-analysis published in 2018 found that second-line ultrasound, computed tomography (CT), and MRI had comparable and high accuracy in helping to diagnose appendicitis in children and adults, including pregnant women 6.

Comparison with Other Imaging Modalities

• Compared to CT, ultrasound has the advantage of lacking ionizing radiation, making it a safer choice for pediatric patients 3, 4.
• MRI has been shown to have high sensitivity and specificity in diagnosing appendicitis, but its accessibility and cost limit its more widespread use 2, 4.
• CT is often reserved for ambiguous cases where ultrasound results are inconclusive, due to its robust specificity 3.

Clinical Implications

• The use of ultrasound as the first-line imaging modality for diagnosing appendicitis in pediatric patients can help reduce ionizing radiation exposure and cost 2, 5.
• Clinical reassessment and complementary imaging with MRI or CT may be necessary in cases where ultrasound results are non-diagnostic or inconclusive 5, 6.