Diagnostic Performance of Three-Phase Bone Scan for Complex Regional Pain Syndrome Type 1 with Optimally Modified Image Criteria

Abstract

Purpose: Although the three-phase bone scan (TBPS) is one of the widely used imaging studies for diagnosing complex regional pain syndrome type I (CRPS-1), there is some controversy regarding the TPBS image criteria for CRPS-1. In this study, we modified the image criteria using image pattern and quantitative analysis in the patients diagnosed using the most recent consensus clinical diagnostic criteria. Materials and Methods: The study included 140 patients with suspected CRPS-1 (CRPS-1, n = 79; non-CRPS, n = 61; mean age 39 ± 15 years) who underwent TPBS. The clinical diagnostic criteria for CRPS-1 revised by the Budapest consensus group were used for confirmative diagnosis. Patients were classified according to flow/pool and delayed uptake (DU) image patterns, and the time interval between the initiating event and TPBS (TIevent-scan). Quantitative analysis for lesion-to-contralateral ratio (LCR) was performed. Modified TPBS image criteria were created and evaluated for optimal diagnostic performance. Results: Both increased and decreased periarticular DU were significant image findings for CRPS-1 (CRPS-1 positive-rate = 73% in the increased DU group, 75% in the decreased DU group). The TIevent-scan did not differ significantly between the different image pattern groups. Quantitative analysis revealed an LCR of 1.43 was the optimal cutoff value for CRPS-1 and diagnostic performance was significantly improved in the increased DU group (area under the curve = 0.732). Given the modified image criteria, the sensitivity and specificity of TPBS for diagnosing CRPS-1 were 80% and 72%, respectively. Conclusions: Optimally modified TPBS image criteria for CRPS-1 were suggested using image pattern and quantitative analysis. With the criteria, TPBS is an effective imaging study for CRPS-1 even with the most recent consensus clinical diagnostic criteria. © 2011 Korean Society of Nuclear Medicine.