Abstract:Objective: To investigate the relationship between transrectal biplane ultrasound (TR-BU) imaging features, contrast-enhanced ultrasound (CEUS) parameters, and bone metastasis (BM) in prostate cancer (PCa), and to evaluate their predictive value for BM when combined with clinical indicators. Methods: A total of 140 patients with PCa were enrolled and categorized into a non-bone metastasis group (n=75) and a bone metastasis group (n=65). Differences in clinical indicators, TR-BU features, and CEUS parameters between the two groups were compared. Independent risk factors associated with PCa BM were identified using multivariable Logistic regression analysis, and a combined predictive model was constructed. The predictive performance of the model was assessed using receiver operating characteristic (ROC) curve analysis. Results: Significant differences were observed between the two groups in clinical factors [alkaline phosphatase (ALP), total prostate-specific antigen (TPSA), Gleason score (GS)], TR-BU features (prostatic capsule invasion, unclear boundary between inner and outer gland, asymmetric blood flow distribution, diffuse distribution of cancerous foci), and CEUS parameters [arrival time (AT), time to peak (TTP), peak intensity (PI), and heterogeneous enhancement] (P<0.05). Multivariable Logistic regression analysis identified prostatic capsular invasion, shortened AT, TPSA >50 ng/mL, and elevated ALP as independent risk factors for PCa BM. The combined predictive model incorporating these factors yielded an area under the ROC curve (AUC) of 0.935, with a sensitivity of 90.8% and a specificity of 82.7%. Conclusion: TR-BU imaging features and TR-CEUS parameters are associated with BM in PCa. Combining these parameters with clinical indicators such as TPSA and ALP demonstrates good predictive value for assessing the risk of bone metastasis in PCa patients.