What is the best imaging modality for a patient suspected of having a hiatal hernia, considering their medical history and potential complications?

Hiatal Hernia Imaging

Primary Recommendation

For suspected hiatal hernia, obtain a biphasic esophagram (double-contrast upper GI series) as the initial imaging study, which achieves 88% sensitivity and provides both anatomic and functional information about the hernia, esophageal length, strictures, and gastroesophageal reflux. 1, 2

Initial Imaging Algorithm

First-Line: Fluoroscopic Studies

The American College of Radiology designates fluoroscopic studies as "usually appropriate" for initial imaging of suspected hiatal hernia, with three equivalent options: 1

• Biphasic esophagram - Combines double-contrast views (optimizes detection of inflammatory conditions and mucosal abnormalities) with single-contrast views (optimizes detection of hiatal hernias, esophageal rings, and strictures), achieving the highest sensitivity of 88% 1, 2

• Double-contrast upper GI series - Most useful test for diagnosing hiatal hernia presence and size, providing anatomic and functional information on esophageal length, strictures, gastroesophageal reflux, and reflux esophagitis with 80% sensitivity 1, 2

• Single-contrast esophagram - May delineate the hernia and reveal reflux, lower esophageal rings, or strictures, though it cannot reveal mucosal irregularities from reflux disease (77% sensitivity) 1

For large hiatal hernias, include a complete upper GI series evaluation of the stomach to assess hernia size and subtype. 1, 2

When to Use CT Scan

CT scan with IV contrast is NOT first-line for uncomplicated hiatal hernia but becomes the gold standard for complicated or emergency presentations: 1, 2

• Use contrast-enhanced CT of chest and abdomen when:

  • Chest X-ray findings are inconclusive but clinical suspicion remains high 2, 3
  • Evaluating for complications (gastric obstruction, strangulation, volvulus, incarceration, ischemia) 1, 3
  • Suspected diaphragmatic hernia in trauma patients 1, 3

• CT findings indicating complications include: 3

  • Absence of gastric wall contrast enhancement (ischemia)
  • Intestinal wall thickening with target enhancement
  • Diaphragmatic discontinuity, "collar sign", "dependent viscera" sign

CT has 14-82% sensitivity and 87% specificity for complicated diaphragmatic hernias, superior for determining presence, location, and size of diaphragmatic defects. 2, 3

Critical Caveats and Pitfalls

Avoid These Common Errors

• Do NOT order CT as first-line imaging - Fluoroscopic studies are more appropriate and informative for uncomplicated hiatal hernia 1, 2, 3

• Do NOT use non-contrast CT - It provides limited assessment of vascular structures and cannot adequately visualize complications like ischemia or strangulation 3

• Do NOT rely on chest X-ray alone - Normal chest radiographs occur in 11-62% of diaphragmatic hernias, with sensitivity of only 2-60% 1, 3

• Do NOT skip barium studies before antireflux surgery - The American College of Surgeons' Esophageal Diagnostic Advisory Panel recommends all patients being considered for antireflux surgery undergo barium esophagogram 2

Diagnostic Discordance

Research reveals significant discordance between imaging modalities: 4, 5, 6

• Barium swallow shows no correlation with manometry or endoscopy findings, though it provides the highest detection rate (76.8%) 4
• Endoscopy has 97.5% detection rate versus barium swallow's 75% when correlated with intraoperative findings 6
• High-resolution manometry has better specificity (95%) than endoscopy (68%) but similar poor sensitivity (52% vs 55%) 5

Because of high false-negative rates across all modalities, negative results by any single test mandate additional testing before excluding hiatal hernia. 5

Special Populations

Pregnant Patients

For pregnant patients with suspected non-traumatic diaphragmatic hernia: 1, 3

• First: Ultrasonography (avoids radiation)
• Second: MRI if ultrasonography is inconclusive

Trauma Patients

For stable trauma patients with suspected diaphragmatic hernia: 1

• Contrast-enhanced CT scan of chest and abdomen (strong recommendation)
• For lower chest penetrating wounds: diagnostic laparoscopy

Preoperative Evaluation

All patients being considered for antireflux surgery require: 2

• Barium esophagogram (mandatory per American College of Surgeons)
• Endoscopy (to evaluate for esophagitis, strictures, Barrett's esophagus)
• Consider manometry if motility disorder suspected