CT findings of bowel necrosis are, 1) poor or absent enhancement of bowel wall on intravenously contrast-enhanced CT, 2) increased attenuation of bowel wall on non-contrast CT (hemorrhagic necrosis), 3) free air, 4) gas in portal vein or SMV, 5) pneumatosis (intramural gas), 6) wall thickening with or without target sign, 7) ascites, 8) thickening of peritoneum, mesentery or retroperitoneal fascia adjacent to bowel wall. Specificity is high in 1, 2 and 5.
There is ascites in Fig.1 and Fig.7 (reference mark). Dilated (>2.5cm) small intestine shows lack of contrast enhancement of the wall, or only slightly enhanced compared with rectum (R), sigmoid colon (S) of Fig. 6 and other small intestines (SB) of Fig.2 and Fig.3. Furthermore, there is the linear gas (white arrowheads) along the wall without forming niveau (air-fluid level) indicating pneumatosis (intramural gas) due to small bowel necrosis. Surgery revealed small bowel necrosis caused by strangulated small bowel obstruction with adhesion and torsion.

Reference case (pneumatosis of right colon): A 78-year-old male presented with abdominal pain and fullness after no bowel movement for 5 days.
This is the case which shows pneumatosis (intramural gas: white arrowhead) of dilated cecum and ascending colon on abdominal plain erect film, caused by obstructive transverse colon cancer. Cecum perforated 3 days later under NG tube decompression.