Bone SPECT/CT in the diagnosis and treatment decision making of axial pain.

Abstract

Purpose: To explore the usefulness of bone SPECT/CT for providing additional information to Magnetic Resonance Imaging (MRI) in patients with axial pain, and for guiding the site of spinal injections.

Methods: We studied 194 patients with axial pain evaluated with SPECT/CT and MRI. Imaging abnormalities were classified according to location and diagnosis of pain generators. Patient outcomes after SPECT/CT guided spinal injection were evaluated during clinical follow-up. Descriptive analyses and kappa coefficient were performed for facet joint arthropathy detection and degenerative disc disease between imaging modalities.

Results: MRI showed 44.3% more abnormalities than SPECT/CT (329 vs. 228). However, SPECT/CT detected 17% more patients with facet joint arthropathy compared to MRI (43.3% vs. 26.3% respectively). Imaging agreement for diagnosing degenerative disc disease was moderate (κ: 0.44; 95% CI, 0.32-0.56), but only fair for facet joint arthropathy (κ: 0.35; 95% CI, 0.28-0.42). The response to spinal injections guided by SPECT/CT imaging was assessed in 56 patients with facet joint arthropathy. Among these, 26 /56 had a history of previous spinal injections guided by physical examination. In this group, the response was effective or partially effective in 65.4% of patients and ineffective in 34.6%. After a second injection guided by SPECT/CT, the response rate increased to 88.4%, with only 11.6% remaining ineffective, resulting in an absolute benefit of 23.4%. In 30/56 patients with no prior history of spinal injections, the therapy was effective or partially effective in 93.3%, while 6.7% did not show any improvement in pain after SPECT/CT-guided spinal injections.

Conclusion: Bone SPECT/CT imaging complements MRI by providing valuable information to identify pain generators. In facet joint arthropathy, it improves the effectiveness of pain relief when used to guide spinal injections.