99mTc(V)-DMSA scintigraphy in monitoring the response of bone disease to vitamin D3 therapy in renal osteodystrophy

Renal osteodystrophy (ROD) is a common and serious complication for uremic patients and patients are treated with 1,25-dihydroxy vitamin D-3. The bone scanning agent Tc-99m-phosphate has also been used to evaluate in ROD but it is not clear that bone scintigraphy has a role in the follow-up of treatment. In this study Tc-99m(V)-DMSA scintigraphy was performed in eleven patients [age 40.7 +/- 17.3 (mean +/- SD) yr] with ROD before and after vitamin D-3 therapy. Images were obtained after hemodialysis performed following tracer injection to maintain normal blood levels of the radiopharmaceutical and to reduce soft tissue activity. Lumbar vertebra-to-soft tissue uptake ratios (LUR) were quantified with the planar Tc-99m(V)-DMSA images. Alkaline phosphatase and parathyroid hormone levels after treatment had significantly decreased compared with pre-therapy. In all patients there was visually decreased uptake in bone structures after treatment. After treatment the mean LUR ratio was significantly lower than those of before treatment (3.59 +/- 2.63 vs. 1.65 +/- 0.62; p = 0.01). LUR values were correlated with pre-therapy alkaline phosphatase and parathyroid hormone. These findings indicate that Tc-99m(V)-DMSA scintigraphy is sensitive in evaluating the response of ROD to vitamin D-3 therapy.