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

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.

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.

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.

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.