Elastic modulus of the prostate: a new non-invasive feature to diagnose bladder outlet obstruction in patients with benign prostatic hyperplasia.

The purpose of our study was to develop a reliable method for the non-invasive evaluation of bladder outlet obstruction (BOO) caused by benign prostate hyperplasia (BPH). In our study, the International Prostate Symptom Score was assessed in, and trans-rectal ultrasound (TRUS) and shear wave sonoelastography (SWE) were performed on, 55 patients with BPH who had undergone urodynamic evaluation (the gold standard diagnostic procedure for BOO). The results indicated that the elastic modulus of the transitional zone was the indicator most strongly correlated with BOO stage (r = 0.666, p < 0.001), and had the largest area under the receiver operating characteristic curve, 0.826 (95% confidence interval: 0.717-0.934, p = 0.001). An elastic modulus of the transitional zone ≥ 32.4 kPa or a total prostate volume ≥ 54.4 mL was diagnostic of BOO, with a sensitivity, specificity, positive predictive value, negative predictive value and accuracy for BOO of 97.2%, 62.5%, 85.4%, 90.9% and 86.5%, respectively. The elastic modulus of the transitional zone is a promising indicator in the assessment of the severity of BOO. In addition, the combination of elastic modulus and total prostate volume was the most accurate indicator in the non-invasive diagnosis of BOO in patients with BPH.