Korean J Urol.  1998 Nov;39(11):1098-1103.

Usefulness of Transition Zone Index in Assessing Benign Prostatic Hyperplasia: Correlation with Symptom Score and Uroflow

  • 1Department of Pathology, Korea University School of Medicine, Seoul, Korea.


PURPOSE: Prostate volume has been known to be poorly correlated with other parameters used to assess benign prostatic hyperplasia(BPH), including symptom score, peak flow rate(Qmax), amount of postvoid residuals(PVR). The purpose of this study was to determine if measurement of the transition zone index(TZI) of the prostate correlated well with other clinical parameters in predicting the degrees of obstruction. MATERIALS AND METHOD: We prospectively evaluated 86 men with symptomatic BPH(mean age: 65.4 years) according to symptoms, Qmax, PVR, transrectal ultrasound volume of the entire prostate and the transition zone. TZI was determined as the ratio between transition zone volume(TZV) and total prostate 1 volume(TV).
Age correlated with symptoms(r=0.29, p=0.006) and PVR(r=0.466, p=0.001); Qmax negatively correlated with age(r=-0.487, p=0.001), symptoms 1 (r=-0.28, p=0.007) and PVR(r=-0.36, p=0.001). Age also correlated with TV(r=0.4, p=0.001), TZV(r=0.435, p=0.001) and, TZI(r=0.36, p=0.001). There was a weak correlations between TV and symptom r=0.23), Qmax(r=0.28), and PVR(r=0.24); a stronger correlation were noted between TZ and symptoms(r=0.33), Qmax(r=-0.35) or PVR(r=0.28). There were significant correlation between TZI and symptoms(r=0.35), Qmax(r=-0.38) or PVR(r=0.30). Age, PVR, 721, and TZV were significantly greater and Qmax were significantly lower in severe (IPSS > or = 20, N=38) symptom group than in moderate(IPSS < or = 19, N=48) one. (p < or = 0.01). On the other hand, the age, PVR, symptom score, TZI, and TZV in low Qmax( < or = 10ml/sec) group were significantly greater than in high Qmax ( > or = 15m1/sec) group. No significant differences of TV were noted either between moderate and severe symptom group or low and high Qmax group.
Transition zone volume or index are parameters that correlates significantly with evaluated parameters of BPH and may serve as a useful method for evaluating obstruction. Studies are underway to determine if transition zone index can be used prospectively to predict and correlate response with therapies designed to ablate prostatic tissue medically or surgically.


Benign prostatic hyperplasia; Transition zone index

MeSH Terms

Prospective Studies
Prostatic Hyperplasia*
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