RESUMO
Objective To investigate the value of prostate-bladder angle (PBA) measured by MRI in the diagnosis of benign prostate obstruction (BPO). Methods A retrospective analysis was carried out on 87 benign prostatic hyperplasia (BPH) patients referred for lower urinary tract symptoms (LUTS) between March 2009 and November 2009. PBA was measured by MRI and urodynamic parameter Qmax was measured as well. With the diagnostic criteria of BPO as Qmax＜10 ml/s, the patients were divided into two groups: obstruction group and non-obstruction group. PBA was compared between these two groups. The sensitivity and the specificity of PBA in diagnosing BPO were also analyzed. Results The age range of the patients was 57-90 years with a median age 73 years; Qmax was 2.325.4 ml/s with median Qmax 7.9 ml/s; PBA was 4°-52° with median PBA 27°. There were 25 patients in the non-obstruction group with PBA between 4°- 21°(13°); in the obstruction group,there were 62 patients with PBA between 15°- 52°(34°). PBA was found statistically different between the obstruction and non-obstruction group (P＜0.01). With the cutoff at PBA≥20°for the diagnosis of BPO, the sensitivity and specificity of the diagnosis were 90. 3 % (56/62)and 96.0% (24/25), respectively. Conclusion PBA measured by MRI is valuable and can be used as a new non-invasive parameter in the diagnosis of BPO.