Musculoskeletal Imaging - Original Article
Comparison of facet joint activity on 99mTc-MDP SPECT/CT with facet joint signal change on MRI with fat suppression
Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, USA
Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA; Department of Immunology, Mayo Clinic, Rochester, Minnesota, USA
Diagn Interv Radiol ; : -
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Purpose: We compared signal change on magnetic resonance imaging (MRI) with fat suppression and bone scan activity of lumbar facet joints to determine if these two imaging findings are correlated.
Methods: We retrospectively identified all patients who underwent imaging of the lumbar spine for pain evaluation using both technetium Tc 99m methylene disphosphonate single-photon emission computed tomography/computed tomography (99mTc‑MDP SPECT/CT) and MRI with at least 1 fat-suppressed T2 or T1 sequence with gadolinium enhancement, within a 180-day interval, at our institution between 1 January, 2008, and 19 February, 2013. Facet joint activity on 99mTc‑MDP SPECT/CT and peri-facet signal change on MRI were rated as normal or increased. Agreement between the 2 examination types were determined with the k and prevalence-adjusted bias-adjusted k (PABAK) statistics.
Results: This study included 60 patients (28 male [47%]), with a mean ± SD age of 49 ±19.7 years (range, 12-93 years). The k value indicated no agreement between 99mTc‑MDP SPECT/CT and MRI (k=–0.026; 95% confidence interval = –0.051, 0.000). The PABAK values were fair to high at each spinal level, which suggests that relatively low disease prevalence lowered the k values. Together, the k and PABAK values indicate that there is some degree of intermodality agreement, but that it is not consistent.
Conclusions: Overall, facet joint signal change on fat-suppressed MRI did not always correlate with increased 99mTc‑MDP SPECT/CT activity. MRI and 99mTc‑MDP SPECT/CT for facet joint evaluation should not be considered interchangeable examinations in clinical practice or research.