This study evaluates quantitative and qualitative patterns of bone scintigraphy and correlates them to laboratory findings and clinical signs to reveal possible inflammatory reactions in RSD. Activity ratios between the affected hand/foot and the contralateral side were calculated in 99mTc DPD-bone scintigraphy for five phases (arterial: 0-30 sec, early blood pool: 0.5-5 min. late blood pool: 5-15 min, 3 hrs early bone, 24 hrs late bone phase) and the presence of five scintigraphic signs in the bone phases was assessed. Activity ratios of all phases correlated with ESR those in the early and late bone phase correlated with alpha 2 globulin and beta globulin concentrations and those in the arterial, the early and late blood pool phase with the gamma globulin concentrations, respectively. Clinical features such as pain, swelling, physical force, temperature differences and the duration of symptoms did not correlate to the activity ratios. However, three signs in the bone phase were negatively correlated to albumin concentrations. Positive correlations were found for alpha 2, gamma globulin concentrations, ESR, neutrophil cell counts and individual uptake patterns. We conclude that the quantitative analysis of five phase bone scintigraphy in RSD reveals different aspects of tracer kinetics and provides different pathophysiological information. Lateralization of regional hyperemia, increased micro vascular permeability and bone metabolism in RSD parallels shifts in protein concentrations and blood cell counts that are suggestive of a subacute inflammatory process, even in patients with no overt signs of inflammation.