Imaging for Enlarged Neck Lymph Node
Order a contrast-enhanced CT of the neck for any adult patient with an enlarged cervical lymph node, as this is the preferred initial imaging modality recommended by both the American Academy of Otolaryngology-Head and Neck Surgery and the American College of Radiology. 1, 2, 3
Why Contrast-Enhanced CT is the Standard
Contrast-enhanced CT is superior to non-contrast imaging because it allows critical assessment of tumor vascular encasement, small nodal metastases with hyperenhancement and necrosis, and extranodal extension involving muscles and blood vessels. 2 Non-contrast CT provides insufficient evaluation of soft tissue extent of disease and cannot adequately distinguish vessels from lymph nodes or identify hypervascular masses. 2
The contrast enhancement enables you to:
- Distinguish enlarged lymph nodes from normal vessels with confidence 4, 5
- Identify malignant features including nodal necrosis, which is highly suggestive of malignancy 3
- Detect occult disease and additional nonpalpable masses 1
- Screen the upper aerodigestive tract for potential primary malignancies 1
Technical Specifications
The CT should extend from the skull base to the thoracic inlet to adequately capture all structures for evaluation. 1 This is particularly important because 50% of masses in level IV and the supraclavicular fossa arise from primary malignancies below the clavicle, including chest and gastrointestinal sources. 1
Use iodinated IV contrast with single-phase imaging (contrast-enhanced only)—dual-phase imaging is not usually necessary. 3
Alternative Imaging Modality
MRI with contrast is an acceptable alternative when CT is contraindicated, offering superior soft tissue contrast resolution. 1, 2, 3 MRI may be preferable for claustrophobic patients who prefer CT, or when radiation exposure is a concern. 1
Critical Pitfalls to Avoid
Never rely on ultrasound alone as initial imaging in adults at risk for malignancy—while ultrasound can be useful as an adjunct for guiding biopsy, contrast-enhanced CT has higher sensitivity for detecting lymph node metastases in the central compartment and retropharyngeal space. 2, 3
Do not order non-contrast CT—it will miss critical diagnostic information about soft tissue extent and vascular involvement. 2
Do not order PET/CT as initial imaging—it is not recommended for initial evaluation of a neck mass, though it may be useful later for staging known malignancies. 2
Special Considerations
Modify the contrast protocol in patients with contrast allergy or renal insufficiency, and adjust imaging recommendations in pregnancy. 1 However, the fundamental need for contrast-enhanced imaging remains unchanged when malignancy risk is present.