Imaging Modalities for Diagnosing Adhesions

Primary Imaging Options

CT scan with intravenous contrast is the preferred imaging modality for identifying adhesions, with approximately 90% accuracy in diagnosing small bowel obstruction caused by adhesions 1, 2, 3
The American College of Radiology recommends CT with IV contrast as the primary diagnostic tool for suspected adhesions, especially when they cause small bowel obstruction, due to its high sensitivity and specificity 1, 4
Multidetector-row CT (MDCT) offers improved diagnostic accuracy with 87% sensitivity and 90% specificity for identifying the etiology of small bowel obstruction 1
CT can demonstrate architectural distortion and tethering in severe adhesive disease, which is useful for diagnosis and treatment planning 6
Signs that suggest adhesive obstruction on CT include a transition zone without other visible cause, closed-loop obstruction, and the "small bowel feces sign" 3

MRI can be valuable in situations where radiation exposure is undesirable, such as in pregnant patients, and can visualize adhesions between viscera 3
Ultrasound is operator-dependent but in experienced hands can provide valuable information about bowel distension and free fluid, and is particularly useful in settings where CT is unavailable or when radiation exposure is a concern 3

Adhesions are not directly visible on standard imaging; diagnosis is typically made by excluding other causes of obstruction, with a strength of evidence level of moderate to high 5, 3
CT has limited sensitivity for low-grade or intermittent obstruction (48-50%), and specialized techniques like CT enteroclysis or CT enterography may be needed for diagnosis 7
The American College of Radiology recommends considering specialized imaging techniques, such as CT enteroclysis or CT enterography, for suspected intermittent or low-grade obstruction, due to their improved sensitivity and specificity 7

For suspected small bowel obstruction with signs of ischemia or perforation, immediate CT with IV contrast is mandatory, as recommended by the World Journal of Emergency Surgery 8
In pregnant patients or those where radiation exposure is a concern, ultrasound followed by MRI if needed is the recommended approach, due to the low risk of radiation exposure and high diagnostic accuracy 3
Plain radiographs have limited value (sensitivity ~70%) and should not be relied upon as the sole imaging modality, according to the World Journal of Emergency Surgery 3