Fig. 2

Abdominal CT for the patients (a) a 49-year-old man with perforation of the duodenal ulcer. Abdominal CT showed signs of subphrenic free gas (white arrow), perihepatic effusion (red arrow). (b) a 78-year-old woman with perforation of the duodenal ulcer. Abdominal CT showed signs of subphrenic free gas (white arrow), duodenal wall edema (orange arrow). (c) a 68-year-old woman with perforated diverticula of the descending colon. Abdominal CT showed inflammation and edema of tissues surrounding the descending colon (white triangle), diverticular lesion in intestinal wall (red triangle). (d) a 50-year-old man with perforation of the sigmoid carcinoma. Abdominal CT showed local bowel wall edema, stingy bubble (green triangle), carcinomatous lesion thickened, lumen stenosis (blue triangle), fecal retention proximal to the lesion (yellow triangle)