Small-Intestinal Intramural Air

Linear, radiolucent, localized contour shadows within the walls of distended small-intestinal loops have been overlooked and undervalued. These intramural air stripes may sometimes be the only roentgen sign of impending perforation in cases of mechanical ileus or of bowel necrosis. A search for such intramural lines hidden in the simple scout abdominal roentgenogram is imperative, for their presence should alert the radiologist to the gravity of the situation and thus influence the immediate surgical decision and approach. In no other abdominal condition is the patient in such immediate danger as in gangrene of the small intestine. The purpose of this paper is to emphasize that intramural air in cases of obstructive ileus is indicative of necrosis and∕or impending perforation. Case I: S.A. was a male infant aged thirty days, with a clinical diagnosis of peritonitis as a result of volvulus of the small intestine (due to malrotation?). A roentgenogram of the abdomen (Fig. 1) with the patient in the supine position was obtained twenty-four hours prior to death. Ring-like and polycyclic radiolucent shadows, characteristic of gas (arrows), were shown, parallel to the outer margins of the dilated small-intestinal loops. Similar areas of increased radiability radiated in a linear, vascular pattern to the periphery of the liver area (arrows); these were interpreted as gas in the portal veins. No separation of loops or evidence of pneumoperitoneum was seen in the upright position. The fixed, crescent-like continuous lines of increased radiability suggested that dissection of air had taken place intramurally along the small-intestinal wall. In addition, the gas in the portal veins suggested that gangrene or severe infection of the intestinal loops was present. Autopsy revealed hemopneumoperitoneum; malrotation of the intestine (incomplete rotation, cecum mobile) with torsion of the mesentery and volvulus; hemorrhagic infarction and necrosis of the mesentery and the intestine; ileus; air bleb formations in the subserous portion of the intestine; fibrinous peritonitis. The liver weighed 150 gm. Unfortunately, no negative or positive statement was made regarding the air in the liver vessels. No blood or intestinal cultures were taken. Case II: Sh. L. was a 50-year-old woman. A roentgenogram of the abdomen (Fig. 2), with the patient in supine position showed markedly dilated intestinal loops and short, crescent-like radiolucent lines parallel to the outer border of the upper bowel in two areas (arrows). Although pneumoperitoneum was present, the localization of radiolucent lines, overlying and following the small intestinal margins, suggested intramural air dissection. At operation, gangrenous, foul-smelling, black, small-intestinal loops were encountered, due to an incarcerated inguinal hernia. A hole of 2 sq. cm. was found at the strangulation point.