Background: Three-phase bone scintigraphy (TPBS) is an established objective diagnostic method for complex regional pain syndrome (CRPS), but its validity remains controversial. The aims of this study were: (i) to re-evaluate the diagnostic performance of TPBS, and (ii) to suggest new TPBS criteria based on the proposed research criteria for CPRS in Budapest (the 2003 Budapest research criteria).
Methods: The medical records of 228 consecutive patients, evaluated using the Budapest research criteria, were retrospectively analysed. Of these, 116 patients were included in the present study, and 69 of 116 were diagnosed to have CRPS based on these criteria. The diagnostic performance of TPBS was assessed by determining its sensitivity, specificity, and positive and negative likelihood ratios, and new criteria for TPBS were identified by pattern analysis using the Budapest research criteria.
Results: The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of TPBS for the diagnosis of CRPS according to the Budapest research criteria were 40.0, 76.5, 1.73, and 0.78, respectively. Furthermore, D-D-D, D-D-S, and D-D-I patterns [i.e. according to decreased (D), symmetrical (S), or increased (I) tracer uptake during Phases I, II, and III] of TPBS were found to be positively predictive for CRPS.
Conclusions: The diagnostic value of a positive TPBS for CRPS is low from the view point of the Budapest research criteria. Our findings suggest that a diagnosis of CRPS using the Budapest research criteria should be considered when decreased patterns of TPBS are observed during Phases I and II.