Evaluation of metastatic bone disease with pentavalent 99Tcm-dimercaptosuccinic acid:: A comparison with whole-body scanning and 4/24 hour quantitation of vertebral lesions

The aim of this study was to establish the value of Tc-99(m)(V)-DMSA scintigraphy in the detection of metastatic bone lesions and compare the results to Tc-99(m)-MDP bone scintigraphy. Thirty-four patients presenting with metastatic bone disease (Group 1) and 12 controls with degenerative skeletal lesions (Group 2) were studied. Conventional bone scanning and Tc-99(m)(V)-DMSA whole-body scanning were performed on all patients. All scans were interpreted visually. Furthermore, lesion-to-normal bone ratios (L/N) in vertebral metastases on the 4 and 24 h bone scans were obtained in 58 lesions of cancer patients and in 23 benign (degenerative) vertebral lesions of the control group. Tc-99(m)-MDP L/N ratios at 24 h (3.08 +/- 0.32) were significantly higher than those at 4 h (2.48 +/- 0.24) in the malignant foci (P < 0.001). No significant difference was observed in benign lesions (P > 0.05). In 167 (164 metastatic, 3 traumatic) of 186 Tc-99(m)-MDP positive lesions (90%) of Group 1, Tc-99(m)(V)-DMSA uptake was observed. The remaining 19 lesions (10%) were Tc-99(m)(V)-DMSA negative. Fourteen of these 19 sites were diagnosed as benign. The remaining five foci were malignant. In four lung cancer metastases showing no Tc-99(m)-MDP uptake, Tc-99(m)(V)-DMSA uptake was observed. There was no Tc-99(m)(V)-DMSA accumulation in any of the Tc-99(m)-MDP positive degenerative lesions of Group 2. All quantitatively evaluated (n = 42) vertebral metastatic foci and two compression fractures in Group 1 showed 99Tcm(V)-DMSA accumulation and an increased Tc-99(m)-MDP L/N ratio at 24 h. A total of 36 degenerative lesions (Groups 1 and 2) and one compression fracture (Group 1) showed neither Tc-99(m)(V)-DMSA uptake nor an increased Tc-99(m)-MDP L/N ratio at 24 h. Our results indicate that quantitative 4/24 h analysis of vertebral lesions on 99Tcm-MDP scans has a similar diagnostic value to Tc-99(m)(V)-DMSA imaging in the detection of bone metastases. However, the accumulation of Tc-99(m)(V)-DMSA in four lung cancer metastases showing no Tc-99(m)-MDP uptake is encouraging and justifies further research in patients with proven bone metastases and negative bone scans. ((C) 2000 Lippincott Williams & Wilkins).