SAT0563 SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY-COMPUTED TOMOGRAPHY IS EQUIVALENT TO MAGNETIC RESONANCE IMAGING IN THE EARLY DIAGNOSIS OF SPONDYLOARTHRITIS: A RETROSPECTIVE STUDY

Abstract

Background:SpA has historically been a difficult clinical diagnosis, especially early diagnosis. Two imaging techniques that address this problem are magnetic resonance imaging (MRI) and Single-Photon Emission Computed Tomography-Computed Tomography (SPECT-CT). Their accuracies have not been adequately compared.Objectives:The purpose of this study is to compare the sensitivities and specificities of SPECT-CT and MRI in SpA.Methods:This retrospective study assessed all patients who underwent SPECT-CT of the sacroiliac joint to assess for SpA. The results of SPECT-CT were compared against MRI for all patients in the cohort who underwent an MRI within 4 weeks of the SPECT-CT. A diagnosis of SpA in the discharge summary was considered the reference standard, and was based on a combination of clinical scenario, response to therapy, imaging,, patient history or lab index.Results:200 patients (173 men; average 22±4 years of age) were included SpA was diagnosed in 189 (AS patients=99 and excluded in 11. SPECT-CT and MRI had similar (P >0 .05;k ¼ 0.74) sensitivities (0.94 vs 0.94),specificities (1.00 vs 1.00),positive predictive values (1.00 vs 1.00),negative predictive values (0.94 vs 0.80),and accuracies (0.97 vs 0.95) when compared to the reference standard.Conclusion:Although MRI remains the initial modality of choice in early diagnosing SpA, SPECT-CT appears diagnostically equivalent and should be considered a viable supplementary or alternative imaging modality particularly if there is contra-indication or inaccessibility to MRI.