The Current State of MR Imaging-targeted Biopsy Techniques for Detection of Prostate Cancer

Abstract

Systematic transrectal ultrasonography (US)-guided biopsy is the standard approach for histopathologic diagnosis of prostate cancer. However, this technique has multiple limitations because of its inability to accurately visualize and target prostate lesions. Multiparametric magnetic resonance (MR) imaging of the prostate is more reliably able to localize significant prostate cancer. Targeted prostate biopsy by using MR imaging may thus help to reduce false-negative results and improve risk assessment. Several commercial devices are now available for targeted prostate biopsy, including in-gantry MR imaging-targeted biopsy and real-time transrectal US-MR imaging fusion biopsy systems. This article reviews the current status of MR imaging-targeted biopsy platforms, including technical considerations, as well as advantages and challenges of each technique. ^© RSNA, 2017.

Figure 1a:

Images in a 75-year-old man with elevated PSA and two prior negative prostate biopsy findings. Poorly marginated elliptical right anterior transition zone lesion (arrow) exhibits (a) decreased T2 signal, (b) decreased apparent diffusion coefficient, and (c) increased high-b-value signal. (d) Screen capture from real-time transrectal US–MR imaging fusion biopsy of the lesion indicates segmented boundary of the prostate (green circle) and segmented boundary of the lesion (yellow outline). Targeted biopsy demonstrated tumor with Gleason score of 5 + 4 in the lesion.

Figure 1b:

Images in a 75-year-old man with elevated PSA and two prior negative prostate biopsy findings. Poorly marginated elliptical right anterior transition zone lesion (arrow) exhibits (a) decreased T2 signal, (b) decreased apparent diffusion coefficient, and (c) increased high-b-value signal. (d) Screen capture from real-time transrectal US–MR imaging fusion biopsy of the lesion indicates segmented boundary of the prostate (green circle) and segmented boundary of the lesion (yellow outline). Targeted biopsy demonstrated tumor with Gleason score of 5 + 4 in the lesion.

Figure 1c:

Images in a 75-year-old man with elevated PSA and two prior negative prostate biopsy findings. Poorly marginated elliptical right anterior transition zone lesion (arrow) exhibits (a) decreased T2 signal, (b) decreased apparent diffusion coefficient, and (c) increased high-b-value signal. (d) Screen capture from real-time transrectal US–MR imaging fusion biopsy of the lesion indicates segmented boundary of the prostate (green circle) and segmented boundary of the lesion (yellow outline). Targeted biopsy demonstrated tumor with Gleason score of 5 + 4 in the lesion.

Figure 1d:

Images in a 75-year-old man with elevated PSA and two prior negative prostate biopsy findings. Poorly marginated elliptical right anterior transition zone lesion (arrow) exhibits (a) decreased T2 signal, (b) decreased apparent diffusion coefficient, and (c) increased high-b-value signal. (d) Screen capture from real-time transrectal US–MR imaging fusion biopsy of the lesion indicates segmented boundary of the prostate (green circle) and segmented boundary of the lesion (yellow outline). Targeted biopsy demonstrated tumor with Gleason score of 5 + 4 in the lesion.

Figure 2a:

Images in a 67-year-old man with elevated PSA and negative transrectal US-guided prostate biopsy finding. Prebiopsy multiparametric MR imaging examination depicts large anterior tumor in prostate apex. Patient decided to undergo MR imaging–targeted biopsy. At the time of biopsy, (a) sagittal T2-weighted image shows rectal needle sleeve in rectum and registered over the MR images. Adjustable needle guide is calibrated at neutral default position. (b) Axial T2-weighted image and apparent diffusion coefficient map show large anterior cancer in apex (crosshair and arrow), which was initially missed by using transrectal US-guided biopsy. Upon identification of target in the prostate, interventional planning software suggested coordinates for needle sleeve orientation. (c) Axial T2-weighted image confirms appropriate orientation of needle sleeve, and three cores are obtained from the target. After biopsy, axial T2-weighted image confirms tip of needle (arrow) within the target. Biopsy results demonstrated prostate cancer with Gleason Score 3 + 4 in the target. T2W = T2-weighted. ADC = apparent diffusion coefficient.

Figure 2b:

Images in a 67-year-old man with elevated PSA and negative transrectal US-guided prostate biopsy finding. Prebiopsy multiparametric MR imaging examination depicts large anterior tumor in prostate apex. Patient decided to undergo MR imaging–targeted biopsy. At the time of biopsy, (a) sagittal T2-weighted image shows rectal needle sleeve in rectum and registered over the MR images. Adjustable needle guide is calibrated at neutral default position. (b) Axial T2-weighted image and apparent diffusion coefficient map show large anterior cancer in apex (crosshair and arrow), which was initially missed by using transrectal US-guided biopsy. Upon identification of target in the prostate, interventional planning software suggested coordinates for needle sleeve orientation. (c) Axial T2-weighted image confirms appropriate orientation of needle sleeve, and three cores are obtained from the target. After biopsy, axial T2-weighted image confirms tip of needle (arrow) within the target. Biopsy results demonstrated prostate cancer with Gleason Score 3 + 4 in the target. T2W = T2-weighted. ADC = apparent diffusion coefficient.

Figure 2c:

Images in a 67-year-old man with elevated PSA and negative transrectal US-guided prostate biopsy finding. Prebiopsy multiparametric MR imaging examination depicts large anterior tumor in prostate apex. Patient decided to undergo MR imaging–targeted biopsy. At the time of biopsy, (a) sagittal T2-weighted image shows rectal needle sleeve in rectum and registered over the MR images. Adjustable needle guide is calibrated at neutral default position. (b) Axial T2-weighted image and apparent diffusion coefficient map show large anterior cancer in apex (crosshair and arrow), which was initially missed by using transrectal US-guided biopsy. Upon identification of target in the prostate, interventional planning software suggested coordinates for needle sleeve orientation. (c) Axial T2-weighted image confirms appropriate orientation of needle sleeve, and three cores are obtained from the target. After biopsy, axial T2-weighted image confirms tip of needle (arrow) within the target. Biopsy results demonstrated prostate cancer with Gleason Score 3 + 4 in the target. T2W = T2-weighted. ADC = apparent diffusion coefficient.

Figure 3:

Images show standardized anatomic localization map from PI-RADS version 2 to designate a suspected cancer lesion seen at prostate MR imaging, consisting of 36 prostate sectors (18 on each side) with designations for left (L) and right (R) seminal vesicles and urethral sphincter (US). a = anterior, AFS = anterior fibromuscular stroma, CZ = central zone, p = posterior, pl = posterolateral, pm = posteromedial, PZ = peripheral zone, TZ = transition zone. For example, left anterior transition zone within the apical one-third of the gland would be sector L, TZa; right posterolateral peripheral zone of the mid gland would be R, PZpl. Source.—Reference .

Figure 4a:

Images in a 68-year-old man with rising PSA to 9.9 ng/mL and two negative transrectal US prostate biopsy findings. (a) A 10-mm poorly marginated nodule in left mid gland peripheral zone (arrow) with decreased T2-weighted signal intensity, decreased apparent diffusion coefficient of 0.773 × 10–3 mm²/sec, increased high-b-value signal of 1500, and focal early enhancement on dynamic contrast-enhanced images yielding an overall score of 4 on PI-RADS version 2. (b) Prostate segmentation is performed by using MR imaging data set to produce a three-dimensional model of the prostate. The prostate (green circle) is outlined by using a semiautomated segmentation tool and delineated as a target (red circle). (c) During fusion biopsy, real-time three-dimensional US model of the prostate is acquired and used to outline the prostate (green circle). The MR imaging and transrectal US three-dimensional models are dynamically fused and visualized side by side. This data set facilitates transrectal US–MR imaging registration and allows projection of the suspicious area seen at MR imaging (red circle) on the transrectal US screen. (d). Finally, targeted biopsies can be performed to generate a final three-dimensional model. Targeted biopsy demonstrated a tumor with Gleason score of 3 + 4. Follow-up prostatectomy confirmed transrectal US–MR imaging fusion biopsy findings. T2W = T2-weighted. DCE = dynamic contrast enhanced. ADC = apparent diffusion coefficient. 3D = three-dimensional.

Figure 4b:

Images in a 68-year-old man with rising PSA to 9.9 ng/mL and two negative transrectal US prostate biopsy findings. (a) A 10-mm poorly marginated nodule in left mid gland peripheral zone (arrow) with decreased T2-weighted signal intensity, decreased apparent diffusion coefficient of 0.773 × 10–3 mm²/sec, increased high-b-value signal of 1500, and focal early enhancement on dynamic contrast-enhanced images yielding an overall score of 4 on PI-RADS version 2. (b) Prostate segmentation is performed by using MR imaging data set to produce a three-dimensional model of the prostate. The prostate (green circle) is outlined by using a semiautomated segmentation tool and delineated as a target (red circle). (c) During fusion biopsy, real-time three-dimensional US model of the prostate is acquired and used to outline the prostate (green circle). The MR imaging and transrectal US three-dimensional models are dynamically fused and visualized side by side. This data set facilitates transrectal US–MR imaging registration and allows projection of the suspicious area seen at MR imaging (red circle) on the transrectal US screen. (d). Finally, targeted biopsies can be performed to generate a final three-dimensional model. Targeted biopsy demonstrated a tumor with Gleason score of 3 + 4. Follow-up prostatectomy confirmed transrectal US–MR imaging fusion biopsy findings. T2W = T2-weighted. DCE = dynamic contrast enhanced. ADC = apparent diffusion coefficient. 3D = three-dimensional.

Figure 4c:

Images in a 68-year-old man with rising PSA to 9.9 ng/mL and two negative transrectal US prostate biopsy findings. (a) A 10-mm poorly marginated nodule in left mid gland peripheral zone (arrow) with decreased T2-weighted signal intensity, decreased apparent diffusion coefficient of 0.773 × 10–3 mm²/sec, increased high-b-value signal of 1500, and focal early enhancement on dynamic contrast-enhanced images yielding an overall score of 4 on PI-RADS version 2. (b) Prostate segmentation is performed by using MR imaging data set to produce a three-dimensional model of the prostate. The prostate (green circle) is outlined by using a semiautomated segmentation tool and delineated as a target (red circle). (c) During fusion biopsy, real-time three-dimensional US model of the prostate is acquired and used to outline the prostate (green circle). The MR imaging and transrectal US three-dimensional models are dynamically fused and visualized side by side. This data set facilitates transrectal US–MR imaging registration and allows projection of the suspicious area seen at MR imaging (red circle) on the transrectal US screen. (d). Finally, targeted biopsies can be performed to generate a final three-dimensional model. Targeted biopsy demonstrated a tumor with Gleason score of 3 + 4. Follow-up prostatectomy confirmed transrectal US–MR imaging fusion biopsy findings. T2W = T2-weighted. DCE = dynamic contrast enhanced. ADC = apparent diffusion coefficient. 3D = three-dimensional.

Figure 4d:

Images in a 68-year-old man with rising PSA to 9.9 ng/mL and two negative transrectal US prostate biopsy findings. (a) A 10-mm poorly marginated nodule in left mid gland peripheral zone (arrow) with decreased T2-weighted signal intensity, decreased apparent diffusion coefficient of 0.773 × 10–3 mm²/sec, increased high-b-value signal of 1500, and focal early enhancement on dynamic contrast-enhanced images yielding an overall score of 4 on PI-RADS version 2. (b) Prostate segmentation is performed by using MR imaging data set to produce a three-dimensional model of the prostate. The prostate (green circle) is outlined by using a semiautomated segmentation tool and delineated as a target (red circle). (c) During fusion biopsy, real-time three-dimensional US model of the prostate is acquired and used to outline the prostate (green circle). The MR imaging and transrectal US three-dimensional models are dynamically fused and visualized side by side. This data set facilitates transrectal US–MR imaging registration and allows projection of the suspicious area seen at MR imaging (red circle) on the transrectal US screen. (d). Finally, targeted biopsies can be performed to generate a final three-dimensional model. Targeted biopsy demonstrated a tumor with Gleason score of 3 + 4. Follow-up prostatectomy confirmed transrectal US–MR imaging fusion biopsy findings. T2W = T2-weighted. DCE = dynamic contrast enhanced. ADC = apparent diffusion coefficient. 3D = three-dimensional.

Figure 5a:

Images show MR imaging–compatible prostate biopsy robot. (a) Transperineal needle placement robot is shown (b) in position between patient’s legs in 70-cm bore 3.0-T magnet.

Figure 5b:

Images show MR imaging–compatible prostate biopsy robot. (a) Transperineal needle placement robot is shown (b) in position between patient’s legs in 70-cm bore 3.0-T magnet.