Added value of ratio of cross diameters of the appendix in ultrasound diagnosis of acute appendicitis

ARTICLE HIGHLIGHTS

Research background

Ultrasound (US) is commonly used for diagnosing acute appendicitis, but the diagnostic performance remains for further improvement. The size of the appendix is crucial for distinguishing between a normal appendix and acute appendicitis.

Research motivation

The maximal outside diameter on the cross section of the appendix > 6 mm has been recommended as a cut-off value for diagnosing acute appendicitis, but the minimal outside diameter and the ratio of the two outside diameters have not been adequately studied.

Research objectives

To investigate if the ratio of the two outside diameters on the cross section of the appendix is a useful parameter for diagnosing acute appendicitis.

Research methods

The investigators measured the two outside diameters on the cross section of a normal appendix and acute appendicitis without perforation using ultrasonography and calculated their ratio. The diagnostic performance of the maximal outside diameter, the ratio of two diameters on the cross section of the appendix, and their combination were compared.

Research results

A ratio of the diameter on the cross section of the appendix ≤ 1.18 was identified as a cut-off value for predicting acute appendicitis. The diagnostic performance based on the ratio of two diameters on the cross section of the appendix ≤ 1.18 was significantly higher than that of the maximal outside diameter.

Research conclusions

Combining the maximal outside diameter and the ratio of two diameters on the cross section of the appendix improved diagnostic performance compared to using the maximal outside diameter alone.

Research perspectives

Further prospective studies are needed to validate the findings and the use of a combination of the maximal outside diameter and the ratio of two diameters for US diagnosis of acute appendicitis.