Diagnostic and Treatment Approach for Abnormal Marrow Signal in the Cervical Spine
MRI of the cervical spine without and with IV contrast is the appropriate initial imaging modality for evaluating abnormal marrow signal in the cervical spine, as it provides excellent bone marrow characterization and helps distinguish between infection, malignancy, and degenerative changes. 1
Initial Diagnostic Workup
Clinical Context Determines Imaging Protocol
The specific clinical presentation dictates the exact imaging approach:
If infection is suspected (fever, elevated inflammatory markers, acute/increasing pain): MRI cervical spine without and with IV contrast is the first-line study, offering 96% sensitivity and 94% specificity for spine infection, with superior detection of epidural abscess, meningitis, and myelitis 1
If malignancy is suspected (known cancer history, constitutional symptoms): MRI cervical spine without and with IV contrast is mandatory, as it detects early marrow changes with 90.6% sensitivity and 95.4% specificity for bone metastasis, and evaluates soft tissue extension into epidural space, neural foramina, and prevertebral tissues 1
If degenerative changes are suspected (chronic pain without red flags): MRI cervical spine without IV contrast may be sufficient initially, though contrast addition improves characterization of complications 1
Why Contrast Matters
The addition of IV contrast is critical because it increases lesion conspicuity, defines the extent of infectious or neoplastic processes, and helps detect peripherally enhancing fluid collections, epidural disease, leptomeningeal involvement, and intramedullary pathology. 1 Precontrast sequences are essential for comparison—contrast-only studies are not useful 1
Interpreting Marrow Signal Abnormalities
Key MRI Signal Characteristics
On T1-weighted images, use internal standards to distinguish pathology from normal hematopoietic marrow:
- Marrow isointense or hypointense to skeletal muscle: 98% likelihood of infiltrative pathology (infection, malignancy) 2
- Marrow isointense or hypointense to intervertebral disc: 98% likelihood of infiltrative pathology 2
- Marrow hyperintense to muscle or disc: 85-100% likelihood of normal red marrow 2
Specific Patterns by Etiology
Infectious spondylitis shows involvement of two adjacent vertebrae with intervening disc, severe bone marrow edema, early endplate destruction, narrowed disc space with water-equivalent T2 signal, and prevertebral/epidural extension 3
Malignant infiltration demonstrates focal or diffuse marrow replacement with soft tissue extension; MRI detects very early marrow space changes before CT or radiographs show abnormalities 1
Degenerative (Modic) changes are common (40.4% prevalence in patients over 50), predominantly Type 2, most frequent at C5/6 and C6/7, and associated with disc herniations 4
When Initial MRI is Equivocal
If MRI findings are questionable or equivocal for myelopathy or structural compression, CT myelography is the next best step to clarify the diagnosis and guide treatment decisions. 5 CT myelography provides superior visualization of severe canal stenosis, foraminal stenosis, bony lesions, and nerve root compression when MRI is inconclusive 5
Alternative Advanced Imaging
If demyelinating disease or inflammatory conditions remain in the differential: Obtain MRI with IV contrast instead of CT myelography; contrast-enhanced MRI is recommended for multiple sclerosis and neuromyelitis optica evaluation 1, 5
If spinal cord ischemia is suspected: Include diffusion-weighted imaging, which shows signal alteration earlier than T2-weighted sequences 5
CT without IV contrast: May be appropriate for early detection of bone abnormalities including osteolysis, erosions, and endplate irregularities, but lacks soft tissue resolution for cord evaluation 1
Critical Clinical Correlation Required
Detailed clinical and laboratory evaluation must accompany imaging interpretation—bone marrow signal changes may represent physiological responses or early pathology requiring follow-up. 6 In a study of 42 patients with incidental marrow signal changes, 7% had hematological malignancies at presentation, and one additional patient developed monoclonal gammopathy during follow-up 6
Laboratory Workup
When abnormal marrow signal is detected, obtain:
- Complete blood count, serum calcium, creatinine 1
- Protein studies including serum/urine electrophoresis, immunofixation, free light chains 1
- Beta-2 microglobulin 1
- Inflammatory markers if infection suspected 1
If clinical suspicion remains high despite negative initial workup, bone marrow biopsy should be performed, and patients require follow-up as marrow signal changes may be preliminary findings. 6
Common Pitfalls to Avoid
Do not assume degenerative changes on MRI correlate with clinical symptoms—spondylotic changes are common in asymptomatic patients over 30 years and correlate poorly with neck pain alone. 5 The agreement between patient symptoms and MRI findings for segmental level is often poor 1
Radiographs are insensitive for early disease, requiring 50-70% bone destruction before detecting osteolytic changes, and lesions <1 cm are frequently not apparent—negative radiographs do not exclude malignancy or infection. 1
Plain radiographs or CT without myelography should not be ordered as the next step when MRI is equivocal, as these lack the soft-tissue resolution needed to evaluate spinal cord and neural compression adequately. 5
Treatment Considerations
Treatment depends entirely on the underlying etiology identified through imaging and clinical correlation:
- Infection: Requires antimicrobial therapy, possible surgical drainage of abscesses, and monitoring for neurologic complications 1
- Malignancy: Necessitates oncologic consultation, staging, and consideration of radiation, chemotherapy, or surgical decompression based on extent and primary tumor type 1
- Degenerative changes: Managed conservatively unless causing myelopathy or radiculopathy with neurologic deficit 1