What is the recommended imaging modality for diagnosing a hiatal hernia?

Imaging for Hiatal Hernia

For suspected hiatal hernia, fluoroscopic studies—specifically a biphasic esophagram or double-contrast upper GI series—are the most appropriate initial imaging modalities, providing both anatomic and functional assessment with superior diagnostic accuracy. 1, 2, 3

Primary Recommended Imaging

Fluoroscopic Studies (First-Line)

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

• Biphasic esophagram combines double-contrast views (optimizing detection of inflammatory conditions and esophagitis) with single-contrast views (optimizing detection of hiatal hernias and esophageal rings/strictures), achieving the highest sensitivity of 88% 3

• Double-contrast upper GI series is the most useful test for diagnosing hiatal hernia, detecting presence and size, providing anatomic and functional information on esophageal length, identifying esophageal strictures, and assessing for gastroesophageal reflux and reflux esophagitis with 80% sensitivity 1, 3

• Single-contrast esophagram may be considered in some instances, though it has lower sensitivity (77%) and may not reveal mucosal irregularities from reflux disease, but can delineate the hernia, reveal reflux, lower esophageal rings, or strictures 1, 3

When to Include Upper GI Series

• For large hiatal hernias, an upper GI series evaluation must be included for complete assessment of the stomach 1, 2

• Fluoroscopic evaluation provides complete evaluation of the hiatal hernia including its size and subtype 1

CT Imaging (Second-Line or Complicated Cases)

When CT is Appropriate

CT scan is the gold standard for diagnosing complicated diaphragmatic hernias, with sensitivity of 14-82% and specificity of 87% 2, 3

CT is superior when:

• Chest X-ray findings are inconclusive but clinical suspicion remains high 2, 3
• Evaluating for complications such as ischemia or strangulation (CT with IV contrast shows absence of gastric wall contrast enhancement, intestinal wall thickening with target enhancement) 2
• Determining presence, location, and size of diaphragmatic defects 2, 3
• Assessing intrathoracic complications of herniated abdominal organs 3

CT Protocol Specifications

• Use contrast-enhanced CT with IV contrast to assess vascular perfusion and detect complications like bowel ischemia or strangulation 2
• Scan both abdomen and pelvis, not just abdomen, to capture full extent 2
• Use multiplanar reconstructions to increase accuracy in locating transition zones and hernia defects 2

Important CT Limitations

• CT abdomen with IV contrast is controversial for routine hiatal hernia diagnosis, with insufficient literature support 2
• Non-contrast CT offers limited assessment of vascular structures and may not adequately visualize potential complications 2

Alternative Imaging Modalities

MRI (Special Populations)

• In pregnant patients with suspected non-traumatic diaphragmatic hernia, ultrasonography is the first diagnostic study, followed by MRI if necessary 2, 3

• Real-time MRI at 3.0 Tesla provides comparable diagnostic accuracy to endoscopy (sensitivity 74% vs 80%, p=0.4223), with ability to visualize hernias during Valsalva maneuver that are occult on static sequences 4

High-Resolution Manometry

• High-resolution manometry has better specificity (95.12%) than endoscopy (68.29%) for ruling out overt Type-I sliding hiatal hernia, though both have high false negative rates (47-45%) 5

• Manometry can detect subtle disruption with axial separation >2 cm between lower esophageal sphincter and crural diaphragm 6, 5

Critical Pitfalls to Avoid

• Never order CT as first-line imaging for hiatal hernia when fluoroscopic studies are more appropriate and informative 2

• Do not rely on chest X-ray alone—normal chest radiographs occur in 11-62% of diaphragmatic hernias 2, 3

• Failing to include upper GI series evaluation when a large hiatal hernia is suspected results in incomplete assessment 2

• Using non-contrast CT when vascular assessment is needed, particularly when evaluating relationship between hernia and cardiac structures 2

• Negative results on either endoscopy or manometry do not rule out hiatal hernia and mandate additional testing 5

Clinical Context for Surgical Planning

• All patients being considered for antireflux surgery should undergo barium esophagogram per the American College of Surgeons' Esophageal Diagnostic Advisory Panel 3

• Fluoroscopic studies provide essential preoperative anatomical information including esophageal length, which is critical for surgical planning 1, 3