Imaging Modalities for Hernia Diagnosis

Initial Diagnostic Approach

The American College of Radiology recommends contrast-enhanced CT scan of the abdomen and pelvis with intravenous contrast as the imaging modality of choice to rule out most abdominal hernias, providing superior sensitivity and specificity for identifying hernia location, contents, and complications 1
For internal hernias, CT with both IV and oral contrast is mandatory, as these cannot be diagnosed clinically and carry high morbidity if missed 1, 2
The Society of Abdominal Radiology suggests that key CT findings for internal hernias include clustered/crowded dilated bowel loops, engorged and displaced mesenteric vessels, the "whirlpool sign" (swirled mesenteric vessels), and displacement of adjacent structures 2

The American College of Radiology recommends scanning both abdomen and pelvis, not just abdomen, to capture the full extent of potential hernias 2
The use of multiplanar reconstructions is essential to increase accuracy in locating transition zones and hernia defects 2
IV contrast is essential to assess vascular perfusion and detect complications like bowel ischemia or strangulation 2

For pregnant patients with suspected diaphragmatic hernia, the American College of Obstetricians and Gynecologists recommends using ultrasound first, followed by MRI if necessary, to limit radiation exposure 2
For trauma patients (stable), the Eastern Association for the Surgery of Trauma recommends contrast-enhanced CT of chest and abdomen for suspected diaphragmatic hernia 2

The American College of Radiology suggests that bowel wall thickening with target enhancement on CT suggests ischemia 1
The absence of bowel wall contrast enhancement on CT indicates strangulation 2
The presence of pneumatosis intestinalis or portal venous gas on CT signifies bowel necrosis 1
The "whirlpool sign" on CT indicates mesenteric volvulus with internal hernia 2