Three-dimensional contrast-enhanced power Doppler ultrasonography and conventional examination methods: the value of diagnostic predictors of prostate cancer.

OBJECTIVE To investigate the value of three-dimensional contrast-enhanced power Doppler ultrasonography (3D-CE-PDU) in the diagnosis of prostate cancer and to compare 3D-CE-PDU with digital rectal examination (DRE), prostate-specific antigen (PSA) levels, grey-scale ultrasonography (GSU) and PDU. PATIENTS AND METHODS The study comprised 30 patients with localized prostate cancer scheduled to undergo radical prostatectomy and 29 with clinical BPH scheduled to undergo transurethral microwave thermotherapy. The 3D-CE-PDU examinations were carried out using 2.5 g of microbubble ultrasound contrast medium; the images were stored digitally to allow off-line analysis. All the reconstructed 3D images of the prostate were evaluated blindly in random order by two investigators (one expert and one novice). The images were scored according to asymmetry (0-2) and vessel distribution (0-3). Marked asymmetry (2) and/or a focal increase in vascularity (> 2) were considered as suspicious for prostate malignancy. Diagnostic predictions using the DRE, PSA level, GSU, PDU, 3D-CE-PDU and their combinations were investigated using receiver operating characteristic (ROC) curves. RESULTS True-positive and true-negative rates of the 3D-CE-PDU were 87% (26/30) and 79% (23/29), respectively, for the expert observer. The sensitivity of 3D-CE-PDU was higher than that of DRE, GSU and PDU, but not PSA level, and the specificity was lower, again except for PSA level. However, when compared with those of the other modalities in single-test evaluations, 3D-CE-PDU, and a combination of 3D-CE-PDU and PSA level, had the largest area under the ROC curve (0. 830 and 0.933, respectively). The diagnostic agreement between the examiners was 76% (Cohen kappa statistic, 0.5). CONCLUSION In this selected group of patients, 3D-CE-PDU alone was a better diagnostic tool than the DRE, PSA level, GSU or PDU alone. The most suitable diagnostic predictor for prostate cancer was a combination of 3D-CE-PDU and PSA level.