How to diagnose acute appendicitis: ultrasound first.

Abstract

Acute appendicitis (AA) is a common abdominal emergency with a lifetime prevalence of about 7 %. As the clinical diagnosis of AA remains a challenge to emergency physicians and surgeons, imaging modalities have gained major importance in the diagnostic work-up of patients with suspected AA in order to keep both the negative appendectomy rate and the perforation rate low. Introduced in 1986, graded-compression ultrasound (US) has well-established direct and indirect signs for diagnosing AA. In our opinion, US should be the first-line imaging modality, as graded-compression US has excellent specificity both in the paediatric and adult patient populations. As US sensitivity is limited, and non-diagnostic US examinations with non-visualization of the appendix are more a rule than an exception, diagnostic strategies and algorithms after non-diagnostic US should focus on clinical reassessment and complementary imaging with MRI/CT if indicated. Accordingly, both ionizing radiation to our patients and cost of pre-therapeutic diagnosis of AA will be low, with low negative appendectomy and perforation rates.Main Messages• Ultrasound (US) should be the first imaging modality for diagnosing acute appendicitis (AA).• Primary US for AA diagnosis will decrease ionizing radiation and cost.• Sensitivity of US to diagnose AA is lower than of CT/MRI.• Non-visualization of the appendix should lead to clinical reassessment.• Complementary MRI or CT may be performed if diagnosis remains unclear.