Initial experience of magnetic resonance imaging/ultrasonography fusion transperineal biopsy: Biopsy techniques and results for 75 patients

Abstract

Purpose: The aim of this study is to describe the technique and to report early results of transperineal magnetic resonance imaging and ultrasonography (MRI-US) fusion biopsy.

Materials and methods: A total of 75 patients underwent MRI-US fusion transperineal biopsy. Targeted biopsy via MRI-US fusion imaging was carried out for cancer-suspicious lesions with additional systematic biopsy. Detection rates for overall and clinically significant prostate cancer (csPCa) were evaluated and compared between systematic and targeted biopsy. In addition, further investigation into the detection rate according to prostate imaging reporting and data system (PI-RADS) score was done. Results of repeat biopsies were also evaluated.

Results: Overall cancer detection rate was 61.3% (46 patients) and the detection rate for csPCa was 42.7% (32 patients). Overall detection rates for systematic and targeted biopsy were 41.3% and 57.3% (p<0.05), respectively. Detection rates for csPCa were 26.7% and 41.3%, respectively (p<0.05). The cancer detection rates via MRI fusion target biopsy were 30.8% in PI-RADS 3, 62.1% in PI-RADS 4 and 89.4% in PI-RADS 5. Rates of csPCa missed by targeted biopsy and systematic biopsy were 0.0% and 25.0%, respectively. The cancer detection rate in repeat biopsies was 61.1% (11 among 18 patients) in which 55.5% of cancer suspected lesions were located in the anterior portion.

Conclusions: Transperineal MRI-US fusion biopsy is useful for improving overall cancer detection rate and especially detection of csPCa. Transperineal MRI-US targeted biopsy show potential benefits to improve cancer detection rate in patients with high PI-RADS score, tumor located at the anterior portion and in repeat biopsies.

Keywords: Biopsy; Magnetic resonance imaging; Prostatic neoplasms; Ultrasonography.

Fig. 1. (A) The set-up of the probe which was attached to a brachytherapy grid with 5-mm spacing and cradle. (B) Biopsy through grid guided by fusion software.

Fig. 2. (A) Sagittal Real-time US targeting of the ROI. ROI 1 (red), ROI 2 (purple), and prostate contour (green). Note that the 3-D model is made, demonstrating the biopsy tract (yellow rod). (B) A 3-D magnetic resonance imaging model assembled by axial and sagittal plane images. ROI, region of interest; 3-D, three-dimensional.

Fig. 3. (A) A 69-year-old man with prostate-specific antigen (PSA) 8.7, Gleason 4+3 cancer in 5 core after initial biopsy. Left transitional lesion of highest suspicion identified on multiparametric magnetic resonance imaging (arrows). (B) A 67-year-old man with PSA 5.6, Gleason 3+3 cancer in 2 core after initial biopsy (from left to right; T2-weighted image, Apparent-diffusion coefficient, dynamic contrast enhancement T1WI) (arrows).