Imaging in prostate cancer diagnosis: present role and future perspectives

Prostate cancer (PCa) remains a major health concern for the male population. Detection and primary diagnosis of PCa are based on digital rectal examination, serum prostate-specific antigen levels, and transrectal ultrasound (TRUS)-guided random biopsy. Moreover, the gold standard for detecting PCa, systematic biopsy, lacks sensitivity as well as grading accuracy. This review summarizes recent developments of ultrasonography modalities and functional magnetic resonance imaging (MRI) in the diagnosis of PCa. A comparison between the different methods is presented, including their clinical value and usefulness. It is concluded that innovative ultrasound techniques (including ultrasound contrast agents, 3-D and 4-D sonography, elastography and harmonic sonography) promise benefits in comparison to standard TRUS to accurately diagnose PCa. Promising advances have been made in the detection of PCa with multiparametric MRI. The combination of conventional and functional MRI techniques (including diffusion-weighted imaging, dynamic contrast-enhanced MRI, and MR spectroscopy) can provide information for differentiating PCa from noncancerous tissue and can be used for MRI-guided biopsies, especially in patients with persistent elevation of serum prostate-specific antigen and previous negative TRUS-guided biopsies. However, functional MRI technique and MRI-guided biopsy remain expensive and complex tools presenting inherent challenges.