3-Tesla magnetic resonance imaging improves the prostate cancer detection rate in transrectral ultrasound-guided biopsy

Abstract

The detection rate of prostate cancer (PCa) using traditional biopsy guided by transrectal ultrasound (TRUS) is not satisfactory. The aim of this study was to determine the utility of 3-Tesla (3-T) magnetic resonance imaging (MRI) prior to TRUS-guided prostate biopsy and to investigate which subgroup of patients had the most evident improvement in PCa detection rate. A total of 420 patients underwent 3-T MRI examination prior to the first prostate biopsy and the positions of suspicious areas were recorded respectively. TRUS-guided biopsy regimes included systematic 12-core biopsy and targeted biopsy identified by MRI. Patients were divided into subgroups according to their serum prostate-specific antigen (PSA) levels, PSA density (PSAD), prostate volume, TRUS findings and digital rectal examination (DRE) findings. The ability of MRI to improve the cancer detection rate was evaluated. The biopsy positive rate of PCa was 41.2% (173/420), and 41 of the 173 (23.7%) patients were detected only by targeted biopsy in the MRI-suspicious area. Compared with the systematic biopsy, the positive rate was significantly improved by the additional targeted biopsy (P=0.0033). The highest improvement of detection rate was observed in patients with a PSA level of 4-10 ng/ml, PSAD of 0.12-0.20 ng/ml², prostate volume >50 ml, negative TRUS findings and negative DRE findings (P<0.05). Therefore, it is considered that 3-T MRI examination could improve the PCa detection rate on first biopsy, particularly in patients with a PSA level of 4-10 ng/ml, PSAD of 0.12-0.20 ng/ml², prostate volume of >50 ml, negative TRUS findings and negative DRE findings.

Keywords: biopsy; magnetic resonance imaging; prostate cancer; transrectal ultrasound.

Figure 1

Images obtained from a 68-year-old patient with a PSA level of 8.4 ng/ml. (A) T2W SPAIR showed no suspicious area in the gland. (B) DWI (arrow) showed a hyperintense area in the left transition zone, which was considered suspicious. (C) TRUS-guided prostate biopsy (arrow) in the suspicious area identified by DWI. (D) Radical prostatectomy specimen (arrow) confirmed the presence of PCa. PSA, prostate-specific antigen; T2W SPAIR, T2-weighted spectral presaturation attenuated inversion recovery; DWI, diffusion-weighted imaging; TRUS, transrectal ultrasound; PCa, prostate cancer.