99 Tc m -MDP SPECT/CT used in diagnosis of pulmonary metastasis from osteosarcoma

Abstract

Objective To observe the incidence of pulmonary metastasis in osteosarcoma and evaluate the diagnostic efficiency of bone scintigraphy and chest CT in detection of pulmonary metastases and its influential factors. Methods A retrospective study was performed in 178 consecutive patients with osteosarcoma who underwent both bone scintigraphy and chest CT examination simultaneously by using a SPECT/CT instrument. Based on the final clinical diagnosis, incidence of pulmonary metastasis in the group was calculated, and the diagnostic efficacy of bone scintigraphy and chest CT was evaluated, re-spectively. Detection rate of bone scintigraphy was correlated to the status of calcification in metastatic le-sions. Serum alkaline phosphatase （ALP） levels was correlated to the occurrence of pulmonary metastasis, calcification status in metastatic lesions and scintigraphic detections. Results Pulmonary metastasis oc-curred in 24.2%patients of all the patients. In the detection of pulmonary metastasis, sensitivity of bone scintigraphy and chest CT was 44.2%and 100%, respectively, and specificity was 100%and 89.6%, re-spectively. Lesion detection on bone scintigraphy was affected by the status of calcification in metastat-ic tumors （χ2=8.4, P<0.01）. It was found that the serum ALP levels was correlated to the occurrence of pulmonary metastasis, but not to the calcification or scintigraphic detections. Conclusions The risk of pulmonary metastasis in patients with osteosarcoma is higher. Using SPECT/CT to obtain bone scintigraphy and chest CT simultaneously will have a higher diagnostic value for detection of pulmonary metastasis, es-pecially for those patients who with elevated serum ALP. Key words: Osteosarcoma; Neoplasm metastasis; Radionuclide imaging; Technetium Tc 99m methylenediphosphonate