Which imaging modalities are recommended for confirming a diagnosis of appendicitis in children?

For confirming a diagnosis of appendicitis in children, ultrasound is the recommended first-line imaging modality due to its safety, lack of radiation, and reasonable diagnostic accuracy in this population. Ultrasound should be used preferentially especially in children, pregnant, and breastfeeding women to reduce radiation exposure risks NICE CKS.

If ultrasound results are inconclusive or non-diagnostic, magnetic resonance imaging (MRI) is the preferred second-line imaging option in children, as it avoids ionising radiation and provides high diagnostic accuracy for acute appendicitis D'Souza et al. 2021Castro-Luna et al. 2025 NICE CKS.

Computed tomography (CT) scans, while highly accurate, are generally reserved for cases where ultrasound and MRI are unavailable or inconclusive, due to concerns about radiation exposure in children NICE CKS. Recent meta-analyses support this imaging pathway, showing that ultrasound followed by MRI if needed optimises diagnostic accuracy while minimising radiation Benabbas et al. 2017Castro-Luna et al. 2025.

Therefore, the recommended imaging strategy in children with suspected appendicitis is to start with ultrasound and proceed to MRI if the diagnosis remains uncertain, reserving CT for exceptional cases NICE CKS Benabbas et al. 2017D'Souza et al. 2021Castro-Luna et al. 2025.