Abstract: Objective To explore the evaluation of PACS image system in the qualitative diagnosis of single bone lesions. Methods 141 patients with single bone lesion were selected from 6 127 patients who were performed radionuclide bone imaging, underwent CT scan immediately after bone scan, radionuclide bone imaging diagnosis, CT diagnosis respectively, and examined with the combination diagnosis in PACS image system, The final diagnosis was proved by clinical follow-up or pathology. Results Seventy-five patients in 141 cases were diagnosed bone metastases. The diagnostic sensitivity of radionuclide bone imaging, CT and the combination diagnosis in PACS image system were 93.33%(70/75), 85.33%(64/75) and 100%(75/75) respectively. The specifcities were 56.06%(37/66), 98.48%(65/66) and 95.45%(63/66) respectively. The accuracy rates were 75.89%(107/141), 91.49%(129/141) and 97.87%(138/141) respectively. The positive predictive values were 70.71%(70/99), 98.46%(64/65) and 92.15%(75/78) respectively. The negative predictive values were 88.10%(37/42), 85.53%(65/76) and 100%(63/63) respectively. Radionuclide bone imaging was superior to CT scan, CT scan was superior to bone scan in specificity, accuracy and the positive predictive value(P<0.05). There were significant differences in specificity, accuracy and the positive predictive value between the combination diagnosis in PACS image system and bone scan (P<0.05), and in sensitivity and the negative predictive value between CT combined bone scan in PACS image system and CT alone (P<0.05). Conclusion Radionuclide bone imaging has high sensitivity, it has the "navigation" function for CT scan. CT contributes to distinguishing benign and malignant single bone lesions with bone scan. The combination of CT and bone scan can improve accordance obviously in diagnosis of solitary bone metastasis.

Key words: neoplasm metastasis, radionuclide imaging, tomography, x-ray computed, PACS image system