Comparison Of MRI And Bone Scintigraphy Detecting Bone Metastasis From Prostate Cancer At Varying Prostate Specific Antigen Levels

Objective: To compare the diagnostic efficacy of MRI and bone scintigraphy in the detection of bone metastasis from prostate cancer.Methods: Sixty-three prostate cancer patients were recruited in this study, All the patients were examined by MRI and bone scintigraphy and chemoluminescence instrument .According to the integrated clinical diagnosis bone metastasis, the patients were cattegorized asmetastastic group and non-metastatic group separately by varying prostate specific antigen levels (≥20μg/L,10～20μg/L,<10μg/L). it was made a comparison between the results of MRI and the results of bone scintigraphy in prostate cancer pantients with serum≥20μg/L,similarly,it was made in prostate cancer pantients with serum <10μg/L .SPSS 13.0 was used to analyze the data.Results: Bone metastasis were identified in 34/63 patients in the entire study group,in 30/46 with serum PSA≥20ng/ml and in 3/10 with serum PSA 10～20 ng/ml and in 1/7 with serum PSA <10μg/L. MRI detected bone metastases in 26/76 pantients with serum PSA≥20ng/ml ;bone scintigraphy detected bone metastases in 26/76 patients with serum PSA≥20ng/ml. The sensitivity ,specificity and accuracy of MR I in the detection of bone metastasis with serum PSA≥20ng/ml was 70.0%,93.75%,78.26%;respectively,The sensitivity, specificity and accuracy of bone scintigrapy in the detection of bone metastasis was 93.33%,56.25%,80.04%. The sensitivity , specificity and accuracy of MRI in the detection of bone metastasis with serum PSA<20ng/ml was 50.00%,86.62%,76.47%;respectively,The sensitivity, specificity and accuracy of bone scintigrapy in the detection of bone metastasis was 75.00%,15.38%,24.91%. The specificity of MRI in the prediction of bone metastasis were higher than that of bone scintigraphy (P=0.037) in patients with serum PSA≥20ng/ml , whereas the sensitivity of bone scintigraphy in the detection of bone metastasis was higher than that of MRI (X2=5.455,P =0.020). The specificity and accuracy of MRI in the prediction of bone metastasis were higher than that of bone scintigraphy (P =0.001,P =0.015) in patients with serum PSA<20ng/ml.Conclusion: The pelvic MRI is useful in the prediction of bone metastasis from prostate cancer. Bone scintigraphy don't need perform for now, when The pelvic MRI indicate non-bone metastases from prostate cancer with serum PSA<20ng/ml.First bone scintigraphy is performed to early detect bone metastases from prostate cancer with serum PSA≥20ng/ml.