From the Guidelines
On an X-ray for constipation, look for excessive fecal loading throughout the colon, particularly in the rectosigmoid region, as well as signs of bowel obstruction, such as dilated loops of bowel and air-fluid levels 1. When evaluating an X-ray for constipation, consider the following key findings:
- Excessive fecal loading throughout the colon, particularly in the rectosigmoid region
- Disruption of the normal bowel gas pattern
- Dilated loops of bowel containing fecal material that appears as mottled, granular opacities
- Fecal impaction may be visible as a large mass in the rectum
- Increased colon diameter beyond the normal 6 cm
- Air-fluid levels indicating obstruction
- Stool in the colon typically appears as mottled densities with air mixed in, creating a characteristic "popcorn" appearance
- In severe cases, the transverse colon can be displaced upward, and the haustra (normal sacculations of the colon) may appear stretched or effaced According to the ESMO clinical practice guidelines, a plain abdominal X-ray may be useful to image the extent of fecal loading and to exclude bowel obstruction 1. However, it is essential to note that the evidence for the use of X-rays in constipation is limited, and further quality studies are needed to determine the optimal tools for practice 1.
From the Research
X-ray Evaluation for Constipation
When evaluating constipation using X-ray, several factors should be considered:
- The presence of fecal impaction, which can be identified by a large amount of stool in the rectum or colon 2, 3
- The extent of colonic distension, which can indicate bowel obstruction 3, 4
- The presence of any anatomic abnormalities, such as strictures or tumors, which can contribute to constipation 5, 4
Key Findings on X-ray
Key findings on X-ray for constipation may include:
- A large amount of stool in the rectum or colon, indicating fecal impaction 2, 6, 3
- Colonic distension, which can indicate bowel obstruction 3, 4
- Air-fluid levels, which can indicate bowel obstruction or ileus 3, 4
- Evidence of stercoral ulcers or perforation, which can be complications of fecal impaction 3, 4
Diagnostic Imaging Modalities
Several diagnostic imaging modalities can be used to evaluate constipation, including:
- Abdominal X-ray, which can identify fecal impaction, colonic distension, and bowel obstruction 3, 4
- Computed tomography (CT) scan, which can provide more detailed images of the colon and rectum 3
- Barium enema, which can identify anatomic abnormalities and colonic motility disorders 5, 3
- Gastrografin enema, which can be used to treat fecal impaction and identify colonic obstruction 6