What is the role of CT/SPECT (Computed Tomography/Single Photon Emission Computed Tomography) fusion study in diagnosing and managing cervical pain?

Role of CT/SPECT Fusion Study in Cervical Pain

CT/SPECT fusion imaging is not recommended as a first-line diagnostic tool for cervical pain but may offer diagnostic value as a secondary imaging modality in cases with suspected facet joint arthropathy and equivocal MRI or CT findings. 1, 2

Appropriate Imaging Algorithm for Cervical Pain

First-Line Imaging

• Radiographs (X-rays) of the cervical spine are the most appropriate initial imaging test for new or increasing nontraumatic cervical pain without "red flags" 1, 2
• Initial radiographic evaluation should include anteroposterior and lateral views to assess for degenerative changes, alignment issues, and in post-surgical cases, hardware integrity 1
• Flexion/extension radiographs may be considered to improve detection of vertebral body nonunion or pseudoarthrosis in post-surgical patients 1

Second-Line Imaging

• MRI cervical spine without contrast is the preferred second-line imaging modality for patients with:
  • Persistent symptoms despite conservative treatment 1
  • Presence of neurological deficits including radiculopathy 1
  • "Red flags" (suspected infection, history of cancer, progressive neurological deficits) 2, 3
• CT cervical spine may be considered when:
  • Better visualization of bony structures is needed 1
  • Hardware complications are suspected in post-surgical patients 1
  • MRI is contraindicated or limited by hardware artifact 1

Role of CT/SPECT in Cervical Pain

Current Evidence

• CT/SPECT is not recommended as an initial examination for cervical spine pain according to the American College of Radiology 1, 2
• Tc-99m bone scan lacks both resolution and specificity in detecting pathology related to acute or worsening neck pain in the absence of red flag symptoms 1, 2
• CT/SPECT may have value in specific clinical scenarios:
  • When initial imaging with MRI or CT is inconclusive 2
  • In patients with suspected pseudoarthrosis or equivocal CT or MRI findings in post-surgical settings 1
  • In localizing facet pain and potentially guiding treatment in patients with chronic neck pain with suspected facet pathology 2, 4

Clinical Applications

• CT/SPECT has shown promising results in identifying potential pain generators in up to 92% of cervical spine scans in patients with chronic spinal pain and non-conclusive MRI/CT findings 4
• CT/SPECT can precisely localize SPECT-positive facet joint targets in approximately 65% of referred patients, potentially guiding therapeutic interventions 4
• In post-surgical patients, CT/SPECT may help identify adjacent segment disease or pseudoarthrosis when other imaging is equivocal 1

Limitations and Considerations

• Recent research shows mixed results regarding CT/SPECT's ability to predict positive response to cervical medial branch blocks, suggesting it should not be used in isolation for treatment decisions 5
• Radionuclide scans may remain positive for a year or more in the region of the operative bed in post-surgical patients, potentially limiting specificity 1
• CT/SPECT findings must be interpreted in the context of clinical symptoms, as degenerative changes are common in asymptomatic individuals 2, 3
• While some studies suggest potential benefits of CT/SPECT-guided surgical interventions for axial cervical pain 6, larger controlled studies are needed to confirm these findings 7

Conclusion

• The diagnostic pathway for cervical pain should begin with radiographs, followed by MRI if symptoms persist or red flags are present 1, 2
• CT/SPECT should be reserved for cases where standard imaging is inconclusive or equivocal, particularly when facet joint arthropathy is suspected as the pain generator 2, 4, 7
• CT/SPECT may be particularly valuable in post-traumatic neck pain to identify occult fractures or periostitis when radiographs are normal or equivocal 8