Role of Shear Wave Elastography in Assessing the Severity of Bladder Outlet Obstruction in Patients with Benign Prostatic Hyperplasia: A Cross-sectional Study

Introduction: Benign Prostatic Hyperplasia (BPH) is a disease prevalent in ageing men. The BPH causes Bladder Outlet Obstruction (BOO) which may even lead to hydronephrosis and renal insufficiency. Therefore, diagnosis of severity of BOO is necessary in the treatment of patients with BPH. Aim: To assess the accuracy of various ultrasound parameters {volume of prostate, Resistive Index (RI) of capsular arteries of prostate and stiffness of prostate} in the prediction of severity of BOO in patients with BPH. Materials and Methods: The cross-sectional study was conducted between November 2020 and January 2021 in the Department of Radiology at at Government Kilpauk Medical College, Chennai, Tamil Nadu, India. Total 55 males between 40 to 80 years of age with symptoms of lower urinary tract obstruction participated. Multi-parametric Transrectal Ultrasound (TRUS) examination of the prostate including Grey scale, Colour Doppler Sonography (CD) and Shear Wave Elastography (SWE) were performed on patients with BPH who had undergone urodynamic evaluation.Volume of the prostate gland, RI of capsular arteries and stiffness or elastic modulus of the prostate gland were measured in the TRUS examination and compared with uroflowmetry which was used as a standard. Receiver Operating Characteristic (ROC) curve was used to assess diagnostic performance of the three ultrasound parameters. The thresholds maximising the Youden index were calculated, and corresponding sensitivity, specificity, positive predictive value, negative predictive value and accuracy are reported. Results: Among the 55 males in the study the mean age of study population was 59.6 years and standard deviation of 7.9. Mean International Prostate Symptom Score among the population was 18.9±4.9. Mean volume of prostate was 33.66 ± 7.166 cc. Mean RI was 0.75±0.11. Mean stiffness of prostate calculated was 40.9±11.3 Kpa. The stiffness or elastic modulus of the prostate was the most strongly correlated indicator with the severity of BOO (R2=0.77, p-value