ROSH Gastrointestinal Practice Exam

What imaging study is considered highly specific for diagnosing small bowel obstruction?

1. Abdominal X-ray

2. CT scan of the abdomen

3. Ultrasound

4. Plain radiography

The correct answer is: CT scan of the abdomen

A CT scan of the abdomen is highly specific for diagnosing small bowel obstruction due to its ability to provide detailed images of the abdominal structures, allowing for clear visualization of the small intestine and any potential blockages. The CT scan can identify the presence and location of an obstruction, assess the degree of distension in the bowel, and evaluate for complications such as ischemia or perforation. It can also help differentiate between various causes of obstruction, such as adhesions, tumors, or hernias, thereby guiding appropriate management. Other imaging studies, while useful, do not provide the same level of specificity or detail. For instance, abdominal X-rays can indicate signs of obstruction, such as air-fluid levels and dilated loops of bowel, but they may miss subtle cases or provide limited information on the cause. Ultrasound can be particularly helpful for pediatric cases or in certain populations, but it is operator-dependent and may not visualize the bowel as clearly as a CT. Plain radiography is essentially the same as an abdominal X-ray and suffers from similar limitations in specificity for diagnosing small bowel obstructions. Overall, the combination of detailed visualization and the ability to assess for complications makes a CT scan the preferred imaging modality for a confident diagnosis of small bowel obstruction.