[Ultrasound indicators of the prostate, urinary bladder and uroflowmetry parameters in the diagnosis of infravesical obstruction in men with benign prostatic hyperplasia]

Benign prostatic hyperplasia (BPH) is one of the most common urologic diseases of males. In patients who failed drug therapy of lower urinary tract symptoms (LUTS) caused by BPH, the most important indication for surgery is the presence of infravesical obstruction (IVO). IVO is detected by pressure-flow studies and is characterized by high detrusor pressure with decreased urinary flow rate. The invasiveness and high cost of this investigation has stimulated a search for non-invasive techniques that could reliably characterize the presence of IVO secondary to BPH.

To determine the value of ultrasound indicators of the prostate, urinary bladder and uroflowmetry parameters in the diagnosis of IVO in men with BPH.

Seventy-six men with moderate and severe LUTS secondary to BPH underwent a comprehensive urological examination, including a clinical history, digital rectal examination, International Prostate Symptom Score (I-PSS), serum prostate-specific antigen (PSA), various ultrasound indicators of the prostate and urinary bladder, uroflowmetry and a pressure/flow study.

Infravesical obstruction (IVO) was detected in 73.1% of men with BPH. IVO was found to have the strongest correlation with ultrasound signs of the intravesical prostatic protrusion (IPP, r = 0,667, p <0,05) compared with the prostate volume, prostate transition zone volume, prostate transition zone index, prostatic urethral angle, urethral length of the transition zone, estimated prostate circumference, prostate peripheral zone thickness, residual urine volume, weight of urinary bladder, the thickness of the detrusor, maximum and average urine flow rates and I-PSS score. The incidence of IVO increased in parallel with the increase of IPP. We established a cut-off value for IPP of 10 mm for the diagnosis of IVO with a sensitivity of 68.2%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 53.3%.

The ultrasound findings of IPP measuring more than 10 mm strongly correlates with the IVO in men with LUTS and BPH as compared with other ultrasound parameters of the prostate, urinary bladder and urinary flow rates. The IPP is anatomical parameter that do not require urination, and is easily detected by both transabdominal and transrectal ultrasound. However, at the PPI values less than 10 mm, the main method for detecting IVO remains the pressure/ flow study.

Urologiia (Moscow, Russia : 1999). 2017 Oct [Epub]

G G Krivoborodov, N S Efremov, A D Bolotov

Department of Urology and Andrology, Medical Faculty of N.I. Pirogov RNRMU of Minzdrav of Russia, Moscow, Russia.

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