What are the next steps in managing a patient with an elevated right hemidiaphragm on chest X-ray (CXR) with clear lung fields and a slightly tortuous thoracic aorta?

Management of Elevated Right Hemidiaphragm on Chest X-ray

Order CT angiography (CTA) of the chest, abdomen, and pelvis with ECG-gating to definitively evaluate the tortuous thoracic aorta and simultaneously assess for other causes of the elevated right hemidiaphragm. 1, 2

Immediate Imaging Strategy

The chest X-ray findings warrant advanced imaging for two reasons:

• The tortuous thoracic aorta requires definitive evaluation with CTA as the primary imaging modality, offering sensitivities up to 100% and specificities of 98-99% for thoracic aortic disease 1, 2
• The elevated right hemidiaphragm is non-specific and can represent multiple pathologies including pulmonary embolism (36% of PE cases), subdiaphragmatic processes (acute cholecystitis, hepatic pathology), diaphragmatic rupture, or phrenic nerve injury 3, 4, 5, 6

CTA Protocol Specifications

The imaging protocol should include:

• ECG-gating to provide motion-free images of the aortic root and ascending aorta 1, 2
• Extension to abdomen and pelvis to assess the entire aorta and evaluate subdiaphragmatic causes of hemidiaphragm elevation 1, 2
• Arterial phase and delayed contrast imaging with thin-section acquisition timed to peak arterial enhancement 1
• Standardized diameter measurements perpendicular to the longitudinal flow axis at defined anatomic locations 1, 2

Critical Aortic Measurements to Document

When reviewing the CTA, measure and document:

• Ascending aorta diameter: Surgical consultation required if ≥5.0 cm 1
• Descending thoracic aorta diameter: Surgical consultation required if ≥4.0 cm 1
• Tortuosity index: High tortuosity (TI >1.29) requires closer surveillance 2
• Growth rate on follow-up: ≥3 mm/year is considered high-risk 1, 2

Differential Diagnosis for Elevated Right Hemidiaphragm

While the CTA is being arranged, consider these etiologies:

Pulmonary Causes

• Pulmonary embolism: Elevated hemidiaphragm occurs in 36% of PE cases, though this is non-specific 3
• The clear lung fields make pneumonia or significant pulmonary disease less likely 3

Subdiaphragmatic Causes

• Acute cholecystitis: Can present with elevated right hemidiaphragm even without sizable intra-abdominal collection 4
• Hepatic pathology: Primary liver cancer shows elevated right hemidiaphragm in 30% of cases 6

Traumatic Causes

• Diaphragmatic rupture: Marked elevation of the right hemidiaphragm (>6 cm above left) is a strong sign of right diaphragmatic rupture, though simple elevation alone is non-specific 5
• Phrenic nerve injury: Can occur from prior procedures or trauma 7

Cardiology Referral

Refer to cardiology for cardiovascular risk factor optimization regardless of final aortic measurements, as aortic tortuosity represents generalized vascular disease 1, 2:

• Blood pressure control: Target <130/80 mmHg 2
• Beta-blocker therapy: Consider to reduce aortic wall stress if any dilation is present 1, 2
• Lipid management and smoking cessation 1, 2

Surveillance Strategy Based on Aortic Diameter

Once maximal aortic diameter is established on CTA, implement surveillance imaging 1, 2:

• 30-39 mm: Every 3 years
• 40-44 mm: Annual surveillance
• 45-49 mm: Every 6 months
• ≥50 mm: Consider intervention

Cardiothoracic Surgery Consultation

Refer to cardiothoracic surgery if 1:

• Ascending aorta diameter ≥5.0 cm
• Descending thoracic aorta diameter ≥4.0 cm
• Growth rate ≥3 mm/year on follow-up imaging

Critical Pitfall to Avoid

Do not assume the elevated right hemidiaphragm is simply age-related or benign without definitive imaging. 4, 5 This finding, particularly when new or unexplained, can represent serious pathology including acute cholecystitis, diaphragmatic rupture, or pulmonary embolism that may be missed if attributed solely to the visible aortic tortuosity. The CTA protocol recommended above will simultaneously evaluate both the aorta and potential causes of hemidiaphragm elevation.