Abstract: The purpose of this study was to investigate the role of CT signs in the perforation of acute appendicitis in the elderly, so as to improve the diagnosis level of the disease. The CT imaging data of 36 cases of acute appendicitis perforated by laparoscopic appendectomy and pathologically confirmed were retrospectively analyzed and compared with 102 cases of acute appendicitis without perforation. Appendiceal diameter, appendiceal fecalith, air accumulation in appendiceal cavity, air accumulation outside appendiceal cavity, peritoneal thickening and abdominal and pelvic effusion were clearly shown, with statistical differences (P<0.05). There was no significant difference in fat density around the appendix (P>0.05). The most direct sign in the qualitative diagnosis of perforation of appendicitis was extravehicular gas (100%). Binary Logistic regression analysis showed that appendix diameter, peritoneal thickening and abdominal and pelvic effusion were the risk factors for appendix perforation (P<0.05). The ROC curve showed that the diameter of the appendix increased (AUC=0.769), the peritoneum thickened (AUC=0.696) and the abdominal pelvic effusion (AUC=0.601). When appendectomy diameter thickened ≥ 12.35 mm, peritoneal thickening combined with abdominal and pelvic effusion combined diagnosis, the area under ROC curve was up to 0.840. It can be seen that CT image features can provide reliable imaging indicators for the perforation of acute appendicitis in the elderly, and have guiding significance for clinical treatment.

Key words: old age, acute appendicitis, perforation, features of CT imaging