Sonographic examination of the appendix in acute infectious enteritis and acute appendicitis

PURPOSE: To use transabdominal sonography to determine the frequency of visualization of the adult normal appendix in patients with suspected acute infectious enteritis (AIE) compared with patients with acute appendicitis (AA) and a control group. METHODS: A total of 296 patients divided into 3 different groups underwent sonographic examination, including 120 randomly selected asymptomatic patients, 91 consecutive patients with AIE, and 85 consecutive patients with AA. In the 3 groups, visualization rate, outer appendiceal diameter, presence or absence of inflamed periappendiceal fat, and location of the appendix were recorded. RESULTS: The visualization rates of the appendix were 49.2%, 70.3%, and 96.5% for the control, AIE, and AA groups, respectively (P < 0.05). The mean +/- SD outer appendiceal diameters for the 3 groups were 4.5 +/- 1.2 mm, 4.5 +/- 1.4 mm, and 7.9 +/- 2.0 mm, respectively. The difference between outer appendiceal diameter in the control and AIE groups was not statistically significant. Periappendiceal inflamed fat was detected in all AA cases, but in none of the AIE cases. CONCLUSION: The appendix was visualized more often in patients with AIE than in the control group, although the outer appendiceal diameter of the AIE group was not significantly different from that of the normal appendix seen in the control group.