Role of Doppler ultrasound and resistive index in benign prostatic hypertrophy


Nobuo Tsuru md, Department of Urology, Hamamatsu University School of Medicine, 20-1 Handayama 1 chow-me, Hamamatsu431-3192, Japan. Email:


Background: The aim of the present study was to assess the resistive index in patients with benign prostatic hypertrophy (BPH) and the role of power Doppler ultrasonography.

Methods: From April 1996 to December 1997, a total of 214 men aged 48–86 years with symptoms of BPH were prospectively enrolled to participate in our study. All patients presented to our clinic with lower urinary tract symptoms. Transrectal ultrasonography was used to calculate the total prostate volume (TPV), transition zone (TZ) volume, transition zone index (TZI = TZ volume/TPV) and presumed circle area ratio (PCAR). Power Doppler imaging was used to identify the capsular and urethral arteries of the prostate and measure its resistive index (RI) value.

Results: The RI of capsular arteries significantly correlated with theTPV, TZ volume, TZI (r = 0.470; P < 0.0001) and PCAR (r = 0.334; P < 0.0001). Correlations were found between the RI of capsular arteries and the International Prostatic Symptom Score (IPSS) (r = 0.389; P < 0.0001), peak flow rate of uroflowmetry (r = -0.393; P < 0.0001).

Conclusion: We demonstrated that an increase of the RI of capsular arteries correlated with increases in the TZI and PCAR in BPH. The lower IPSS and peak flow rate correlated with the high RI of capsular arteries; however, no correlation between the RI of urethral arteries and prostatic parameters was found. The findings suggested that the RI of capsular arteries may become the index for measuring lower urinary obstruction in the future.