Should a patient with known or suspected cancer who presents with new back pain, radicular symptoms, or neurologic deficits undergo a contrast‑enhanced MRI of the entire spine to assess for metastatic disease?

MRI of the Spine for Suspected Malignancy

Yes, patients with known or suspected cancer presenting with new back pain, radicular symptoms, or neurologic deficits should undergo contrast-enhanced MRI of the entire spine (without and with IV contrast) to assess for metastatic disease. 1

Optimal Imaging Protocol

MRI complete spine without and with IV contrast is the imaging modality of choice for evaluating suspected spinal metastatic disease in cancer patients. 1 This approach provides:

• High sensitivity and specificity for detecting both bony/marrow involvement and neural compression from epidural tumor 1
• Superior visualization of intradural and intramedullary metastases, which are multiple in 75% of cases 2
• Critical precontrast images that are essential for accurately assessing enhancement patterns after gadolinium administration 1

Why Complete Spine Imaging

Image the entire spine, not just the symptomatic region, because:

• Multifocal disease is common: 23% of patients with extradural compression have multiple levels involved 2
• Intradural metastases are multiple in 75% of cases 2
• The thoracic spine is most frequently affected (74% of cases), which may be clinically silent initially 2
• Complete spine MRI is specifically recommended when multifocal disease is suspected 1

Contrast Enhancement Rationale

Gadolinium contrast with fat suppression is invaluable for several reasons:

• Detects additional lesions that are invisible on noncontrast sequences—in one study, 9 of 29 lesions were seen only on contrast-enhanced fat-suppressed images 3
• Better delineates epidural disease (7 lesions), paravertebral involvement (9 lesions), and intradural-extramedullary lesions (6 lesions) 3
• Distinguishes abscess from phlegmon and identifies epidural abscesses, which can complicate metastatic disease 1
• Enhances conspicuousness of intramedullary tumors, with enhancement ranging from 70-350% 4

When Contrast Alone Is Insufficient

Never perform MRI with contrast only—precontrast images are mandatory. 1 The American College of Radiology explicitly states that MRI complete spine with IV contrast alone "is not useful as a first-line imaging test" because accurate assessment of enhancement requires comparison with precontrast sequences. 1

Alternative Imaging Considerations

CT has limited utility in this clinical scenario:

• CT without contrast can evaluate osseous integrity (pathologic fractures, bony destruction) but poorly depicts intradural and spinal cord pathologies 1
• CT with contrast may assess epidural abscess but remains inferior to MRI for comprehensive evaluation 1
• CT is useful only for specific questions such as identifying calcifications or precise bone detail after MRI has been performed 1

Critical Pitfalls to Avoid

• Do not obtain targeted/regional spine MRI when cancer is known or suspected—complete spine imaging is necessary to detect multifocal disease 1
• Do not skip precontrast sequences even when malignancy is strongly suspected—enhancement cannot be accurately assessed without baseline images 1
• Do not rely on bone scan or PET/CT as initial imaging—these are not first-line studies and MRI provides superior anatomic detail and neural structure visualization 1
• Do not use CT myelography—this historically important technique has decreased usefulness and is invasive 1

Special Circumstances

When MRI findings don't correlate with clinical presentation, contrast-enhanced images become even more critical. 2 Specifically obtain contrast when:

• Unenhanced appearances are equivocal or don't match symptoms 2
• Intradural or intramedullary disease is suggested on noncontrast sequences 2
• There is concern for epidural abscess complicating metastatic disease 1

Fat-suppressed contrast-enhanced sequences should be specifically requested, as they provide superior lesion detection compared to standard contrast-enhanced images. 3