Benign prostatic hyperplasia: clinical overview and value of diagnostic imaging.

The term benign prostatic hyperplasia has traditionally been used to describe a constellation of obstructive and irritative voiding symptoms that occur in men as they age. Such symptomatology may be due to a variety of causes, including prostatic enlargement. Thus, the term lower urinary tract symptoms has replaced BPH to describe this symptom complex. The evaluation and treatment of LUTS continues to be a significant part of urology practice in the United States, as well as a significant component of medical resource utilization. Currently, indication for treatment in patients with LUTS is most often based on subjective measurements of symptom severity and bother. Consequently, imaging does not play a major role in the evaluation of such patients. Recent data suggest that the size of the prostate gland may predict which patients with LUTS will develop progressive symptoms and complications. Moreover, both prostate size and the histologic composition of BPH may help to select patients for specific treatment options. Thus, radiologic imaging may eventually play a larger role in the diagnosis and treatment of LUTS in the future. After review of the literature, it appears that routine upper urinary tract imaging in patients with LUTS or BPH is not warranted. Selective use of such imaging tests in patients with BPH and either hematuria, laboratory evidence of renal insufficiency (elevated BUN or creatinine), or a history of urinary tract infection, urolithiasis, previous urinary tract surgery, or congenital or acquired renal disease remains indicated. Local imaging of the prostate can be performed with either MR imaging or TRUS. Although MR imaging provides excellent resolution of internal prostatic anatomy, information with respect to the ratio of glandular to stromal tissue in the prostate, and an accurate estimate of prostate volume, its use in patients with BPH is limited by its high cost and limited availability. In contrast, TRUS remains an important tool in the evaluation of patients with prostatic disease. Similar to MR imaging, TRUS provides excellent images of internal prostatic anatomy and an accurate estimate of prostate volume prior to treatment. In addition, this imaging modality is noninvasive, cost-efficient, easily adapted to office use, and able to provide guidance for transrectal prostate biopsy.