Which X‑ray study is indicated for evaluating an upper‑thoracic back mass?

X-ray for Upper Back Mass

For an upper thoracic back mass, obtain anteroposterior (AP) and lateral radiographs of the thoracic spine as the initial imaging study, but recognize that MRI without IV contrast is the definitive modality for characterizing soft tissue masses and should be obtained promptly if the mass is palpable or causing neurologic symptoms. 1, 2

Initial Imaging Approach

Plain radiographs serve as a screening tool but have severe limitations for soft tissue pathology:

• The American College of Radiology recommends AP and lateral views as the minimum standard for thoracic spine imaging 1
• However, plain radiographs cannot characterize soft tissue masses and will miss the pathology entirely if the mass is purely soft tissue in nature 2
• Radiographs are only useful for detecting osseous destruction, spinal deformity, or bony involvement that may accompany the mass 3
• Thoracic spine radiographs are particularly limited due to difficulty in assessment from overlying structures (ribs, scapulae, mediastinum) 3

When to Proceed Directly to MRI

MRI without IV contrast is the single best modality for evaluating soft tissue masses in the upper thoracic spine and should be obtained as the initial study if:

• The mass is palpable and causing neurologic symptoms (such as radiculopathy, numbness, or weakness) 2
• There is clinical concern for nerve root compression or spinal cord involvement 2
• The mass requires characterization for surgical planning 2

MRI provides superior soft tissue resolution to:

• Characterize the mass (lipoma, ganglion, neurofibroma, or other pathology) 2
• Evaluate for nerve root or spinal cord compression 2
• Assess the spinal cord for signal abnormality 2
• Allow complete preoperative surgical planning if intervention is needed 2

When to Add IV Contrast

Obtain MRI without and with IV contrast instead if red flags are present: 2, 4

• Fever or recent infection
• Immunosuppression or IV drug use
• History of cancer
• Unexplained weight loss
• Constant pain unrelieved by rest
• Age >65 years

These features raise suspicion for infection or neoplasm, which require contrast enhancement for optimal detection 3, 2

Role of CT Imaging

CT without IV contrast is complementary but not primary: 2, 4

• CT depicts osseous detail well but misses soft tissue pathology 2
• CT is appropriate only when MRI is contraindicated (pacemaker, severe claustrophobia, metallic implants) or for presurgical bony anatomy assessment 2, 4
• CT with IV contrast alone has no role in soft tissue mass evaluation—there is no literature supporting this 2

Critical Pitfalls to Avoid

• Do not rely on radiographs alone if a soft tissue mass is clinically evident—they will miss the diagnosis entirely 2
• Do not delay MRI if myelopathy signs develop (spasticity, hyperreflexia, gait disturbance, bladder dysfunction)—this requires immediate evaluation 2, 4
• Screen for red flags including progressive neurologic deficits, which escalate urgency for contrast-enhanced MRI 2
• Remember that plain films require 30-40% bone destruction before lesions become visible, so normal radiographs do not exclude significant pathology 1