From the Guidelines
The best imaging modality to evaluate potential small bowel obstruction is a CT scan of the abdomen and pelvis with IV contrast. This recommendation is based on the high diagnostic accuracy of CT scans in detecting small bowel obstruction, with a reported accuracy of more than 90% 4, 5, 17. CT scans with IV contrast provide superior visualization of the bowel, allowing clinicians to identify the location and cause of obstruction, assess bowel wall viability, and detect complications like ischemia [2,3,8,30-32]. The use of IV contrast is preferable for routine imaging of suspected SBO, as it demonstrates whether the bowel is perfusing normally or is potentially ischemic, and provides information about the potential etiology, such as Crohn disease and neoplasm 1.
Some of the key benefits of CT scans with IV contrast include:
- High accuracy for distinguishing SBO from an adynamic small-bowel ileus 6
- Ability to identify the cause of obstruction [17-20]
- Detection of complications like ischemia and strangulation [2,3,8,30-32]
- Guidance for management, including assessment of SBO complications and potential underlying causes like adhesions, hernias, masses, or inflammatory conditions 1
In comparison, other imaging modalities like abdominal X-rays and ultrasound have limited utility in evaluating potential small bowel obstruction. Abdominal X-rays may show dilated bowel loops and air-fluid levels, but they lack sensitivity and specificity compared to CT. Ultrasound has limited utility due to bowel gas interference. Non-contrast CT is an alternative when IV contrast is contraindicated, but it provides less detailed information about bowel wall perfusion and vascular complications 1.
Overall, the use of CT scans with IV contrast is supported by the American College of Radiology, which recommends CT abdomen and pelvis as the best imaging modality for suspected small-bowel obstruction 1.
From the Research
Imaging Modalities for Small Bowel Obstruction
The best imaging modality to evaluate potential small bowel obstruction is a topic of discussion among medical professionals.
- Computed Tomography (CT) scan of the abdomen and pelvis with IV contrast is considered the preeminent imaging modality for evaluating patients with suspected high-grade small-bowel obstruction 2.
- CT scan is superior to small bowel follow-through in identifying masses, malignancies, and features of strangulation 3.
- CT scan is usually the most appropriate and accurate diagnostic imaging modality for most suspected bowel obstructions 4.
Comparison of Imaging Modalities
- Abdominal ultrasound is not considered a primary imaging modality for evaluating small bowel obstruction.
- Abdominal X-ray, flat and upright, may be used as an initial imaging modality, but it is not as accurate as CT scan in diagnosing small bowel obstruction.
- Noncontrast CT scan of the abdomen and pelvis may not be as effective as CT scan with IV contrast in evaluating small bowel obstruction.