A novel spectral ultrasonic differentiation method for marking regions of interest in biological tissue: in vitro results for prostate

OBJECTIVE: The aim of the present study was to evaluate the effectiveness of a new method of spectral analysis of the radiofrequency (RF) ultrasonic echo signal in discriminating neoplastic from non-neoplastic tissue of the prostate gland. MATERIAL AND METHODS: The proposed method was previously set up on ten prostatic glands where cancer had been detected by histology in order to correlate the tumour areas with specific spectral parameters. In the present study sixty prostate specimens of patients undergoing radical retropubic prostatectomy for clinically localized prostate cancer were examined. The surgically removed prostate glands were scanned using an echo signal acquisition apparatus and the spectral parameters were obtained by the wavelet transform. The echographic scans of all cases were then compared with the whole-mount histological sections of the prostate in order to evaluate sensitivity and specificity of the proposed method. RESULTS: The sensitivity and specificity for cancer detection were 93% and 91%, respectively. The specificity was invalidated by the fact that in some of the cases studied, the tumour was located in areas of benign prostatic hyperplasia (BPH). As for the sensitivity, of the three false negative cases two were due to the coexistence of cancer foci and BPH. CONCLUSIONS: Our proposed method, named WAMBLE (Wavelet Analysis Multi Band Local Estimator), is accurate in detecting prostate cancer. Further in vivo studies are warranted to confirm the clinical value of this technique.