Abdominal CT in intestinal obstruction

Table 11: What to look for on the CT in intestinal obstruction

Distended loops of bowel

Transition zone

Mass

Lymph nodes

Organ Metastases

Peritoneal Metastases

A CT scan will show the distended loops quite well. Look for collapsed bowel and follow it proximally to the distended area. This will be evidence of obstruction and will point to the site of obstruction.

With a CT it may be possible to see enlarged lymph glands or evidence of metastatic disease in the liver or peritoneum.

Table 12: Superiority of CT over plain radiology in intestinal obstruction.[FMBF94]

Modality	Sensitivity (%)	Specificity (%)
Plain radiology	46	88
CT with oral contrast	100	83

Sometimes the plain film will not show evidence of intestinal obstruction because the loops do not have much gas in them. Obstruction is usually obvious on a CT scan, see table 12.

Rarer causes of obstruction may be diagnosed pre-operatively on CT scanning. For instance, Spigelian hernia⁶ or an unsuspected laparoscopic port site hernia.