Diagnostic Ability of Transabdominal Ultrasonography for Appendiceal Diverticulitis

Appendiceal diverticulitis (AD) is frequently confused with acute appendicitis (AA); however, AD carries a higher risk of perforation and malignancy than AA. We aimed to evaluate the preoperative diagnostic ability of transabdominal ultrasonography (US) for AD.

We included 74 patients who underwent appendectomy with a preoperative diagnosis of AA, AD, and US within a day of surgery. AD was diagnosed using US by identifying protruding, pouch-like hypoechoic structures beyond the appendiceal margin, whereas it was diagnosed using histopathology by identifying the invagination of the appendiceal epithelium into the muscularis propria.

The median patient age was 45 years (61% males). Among the patients with a US diagnosis of AD, 9 patients had histopathological AD, while one patient did not. The other 64 patients without a US diagnosis of AD did not have histopathological AD. US showed 100% sensitivity, 98% specificity, 90% positive predictive value, 100% negative predictive value, and 99% accuracy for AD. A retrospective review of US images showed that 8 patients exhibited high echoic rims at the border of the hypoechoic structures among the 9 patients with histopathological AD. When this finding was incorporated into the US diagnosis of AD, the specificity increased to 100%.

The diagnostic accuracy of US for AD is high. Not only are protruding pouch-like hypoechoic structures specific for the US diagnosis of AD, but also highly echoic rims at the border.