Real-time Virtual Sonography for navigation during targeted prostate biopsy using magnetic resonance imaging data

Real-Time Virtual Sonography-Guided Ossicle Removal in Unresolved Osgood-Schlatter Disease

Osgood-Schlatter disease (OSD) reduces participation in sports activities for adolescents, and, in unresolved cases of the disease in which daily life or sports activity after skeletal maturity are affected, surgical intervention to remove the ossicle is performed to alleviate symptoms. We present a real-time virtual sonography (RVS)-guided ossicle removal in unresolved OSD. The knee joint angle is set at 20°, which is the same position used in magnetic resonance imaging. A 1.5-cm longitudinal skin incision is made at the medial side of the tuberosity. An ultrasound probe covered with a sterile sleeve is then placed longitudinally at the level of tuberosity. The forceps is inserted to peel the patellar tendon off the posterior side of the ossicle. Then the anterior side of the ossicle is peeled off in both the transverse and longitudinal views. When the ossicle is unstable enough, forceps are used to grasp the ossicle and carefully remove it. RVS can see magnetic resonance imaging information in the surrounding area beyond what can be detected by the ultrasound probe, and RVS enables easy determination of the anatomical position of the ossicle, and removal of the ossicle is achieved with low invasiveness.

Superior detection of significant prostate cancer by transperineal prostate biopsy using MRI-transrectal ultrasound fusion image guidance over cognitive registration

BACKGROUND

The BioJet system allows the fusion of magnetic resonance imaging (MRI) images with real-time transrectal ultrasonography to accurately direct biopsy needles to the target lesions. To date, the superiority of targeted biopsy using the BioJet system over cognitive registration remains unknown.

METHODS

This retrospective study included 171 biopsy-naïve men with elevated prostate-specific antigen (2.5-20 ng/mL) and MRI-positive lesions; 74 and 97 men underwent a four-core targeted biopsy per MRI-positive target lesion and a 14-core systematic biopsy transperineally using the BioJet system and cognitive registration, respectively. Detection rates of significant cancer, defined as grade group ≥ 2 or maximum cancer length ≥ 5 mm, were compared between the BioJet system and cognitive registration using propensity score matching and a multivariate logistic regression model.

RESULTS

After propensity score matching (67 men for each group), the detection rates of significant cancer were significantly higher in the BioJet group than in the cognitive group for both targeted (76% vs. 46%, P = 0.002) and systematic (70% vs. 46%, P = 0.018) biopsy. Multivariate analysis of the entire cohort also showed that the BioJet system was independently associated with significant cancer detection by targeted and systematic biopsy (P < 0.01), along with a higher prostate-specific antigen density and a higher prostate imaging reporting and data system score.

CONCLUSIONS

Transperineal prostate biopsy using the BioJet system is superior to cognitive registration in detecting significant cancer for targeted and systematic biopsies.

3-D Ultrafast Shear Wave Absolute Vibro-Elastography Using a Matrix Array Transducer

Real-time ultrasound imaging plays an important role in ultrasound-guided interventions. The 3-D imaging provides more spatial information compared to conventional 2-D frames by considering the volumes of data. One of the main bottlenecks of 3-D imaging is the long data acquisition time, which reduces practicality and can introduce artifacts from unwanted patient or sonographer motion. This article introduces the first shear wave absolute vibro-elastography (S-WAVE) method with real-time volumetric acquisition using a matrix array transducer. In S-WAVE, an external vibration source generates mechanical vibrations inside the tissue. The tissue motion is then estimated and used in solving a wave equation inverse problem to provide the tissue elasticity. A matrix array transducer is used with a Verasonics ultrasound machine and a frame rate of 2000 volumes/s to acquire 100 radio frequency (RF) volumes in 0.05 s. Using plane wave (PW) and compounded diverging wave (CDW) imaging methods, we estimate axial, lateral, and elevational displacements over 3-D volumes. The curl of the displacements is used with local frequency estimation to estimate elasticity in the acquired volumes. Ultrafast acquisition extends substantially the possible S-WAVE excitation frequency range, now up to 800 Hz, enabling new tissue modeling and characterization. The method was validated on three homogeneous liver fibrosis phantoms and on four different inclusions within a heterogeneous phantom. The homogeneous phantom results show less than 8% (PW) and 5% (CDW) difference between the manufacturer values and the corresponding estimated values over a frequency range of 80-800 Hz. The estimated elasticity values for the heterogeneous phantom at 400-Hz excitation frequency show the average errors of 9% (PW) and 6% (CDW) compared to the provided average values by magnetic resonance elastography (MRE). Furthermore, both imaging methods were able to detect the inclusions within the elasticity volumes. An ex vivo study on a bovine liver sample shows less than 11% (PW) and 9% (CDW) difference between the estimated elasticity ranges by the proposed method and the elasticity ranges provided by MRE and acoustic radiation force impulse (ARFI).

Application of ultrasound imaging in the treatment of urinary tract stones

Urinary tract stones are a common clinical condition that affect millions of individuals worldwide. The management of these stones has evolved significantly over the past 70 years, and ultrasound imaging has emerged as a valuable tool for diagnosis, treatment planning, and follow-up. This review aims to provide an overview of the application of ultrasound imaging in the treatment of urinary tract stones, highlighting its advantages, limitations, and current advancements in the field.

Meta-Learning Initializations for Interactive Medical Image Registration

We present a meta-learning framework for interactive medical image registration. Our proposed framework comprises three components: a learning-based medical image registration algorithm, a form of user interaction that refines registration at inference, and a meta-learning protocol that learns a rapidly adaptable network initialization. This paper describes a specific algorithm that implements the registration, interaction and meta-learning protocol for our exemplar clinical application: registration of magnetic resonance (MR) imaging to interactively acquired, sparsely-sampled transrectal ultrasound (TRUS) images. Our approach obtains comparable registration error (4.26 mm) to the best-performing non-interactive learning-based 3D-to-3D method (3.97 mm) while requiring only a fraction of the data, and occurring in real-time during acquisition. Applying sparsely sampled data to non-interactive methods yields higher registration errors (6.26 mm), demonstrating the effectiveness of interactive MR-TRUS registration, which may be applied intraoperatively given the real-time nature of the adaptation process.

Magnetic Resonance Imaging Guided Prostate Biopsy in Patients with ≥ One Negative Systematic Transrectal Ultrasound-Guided Biopsy: A Systemic Review and Meta-Analysis

The present study aimed to compare prostate cancer (PCa) and clinically significant PCa (csPCa) detection sensitivity between magnetic resonance imaging guided-biopsy (MRI-GB) and transrectal ultrasound-guided biopsy (TRUS-GB) in patients with ≥ 1 negative TRUS-GB, and to explore the additive value of TRUS-GB to MRI-GB. The meta-analysis of 18 studies demonstrated that MRI-GB had a similar sensitivity for PCa detection but a higher sensitivity for csPCa than TRUS-GB. In conclusion, there was limited value in combining TRUS-GB with MRI-GB compared with MRI-GB alone for csPCa detection in patients with one or more negative TRUS-GBs that were suspicious of having PCa.

Prostate Cancer Detection with mpMRI According to PI-RADS v2 Compared with Systematic MRI/TRUS-Fusion Biopsy: A Prospective Study

Background: mpMRI assesses prostate lesions through their PI-RADS score. The primary goal of this prospective study was to demonstrate the correlation of PI-RADS v2 score and the volume of a lesion with the presence and clinical significance of prostate cancer (PCa). The secondary goal was to determine the extent of additionally PCa in inconspicuous areas. Methods: All 157 patients underwent a perineal MRI/TRUS-fusion prostate biopsy. Targeted biopsies as well as a systematic biopsy were performed. The presence of PCa in the probes was specified by the ISUP grading system. Results: In total, 258 lesions were biopsied. Of the PI-RADS 3 lesions, 24% were neoplastic. This was also true for 36.9% of the PI-RADS 4 lesions and for 59.5% of the PI-RADS 5 lesions. Correlation between ISUP grades and lesion volume was significant (p < 0.01). In the non-suspicious mpMRI areas carcinoma was revealed in 19.7% of the patients. Conclusions: The study shows that the PI-RADS v2 score and the lesion volume correlate with the presence and clinical significance of PCa. However, there are two major points to consider: First, there is a high number of false positive findings. Second, inconspicuous mpMRI areas revealed PCa.

Comparison of prostate cancer detection rates in patients undergoing MRI/TRUS fusion prostate biopsy with two different software-based systems

BACKGROUND

Magnetic resonance imaging (MRI)-targeted prostate biopsy is a routinely used diagnostic tool for prostate cancer (PCa) detection. However, a clear superiority of the optimal approach for software-based MRI processing during biopsy procedures is still unanswered. To investigate the impact of robotic approach and software-based image processing (rigid vs. elastic) during MRI/transrectal ultrasound (TRUS) fusion prostate biopsy (FBx) on overall and clinically significant (cs) PCa detection.

METHODS

The study relied on the instructional retrospective biopsy data collected data between September 2013 and August 2017. Overall, 241 men with at least one suspicious lesion (PI-RADS ≥ 3) on multiparametric MRI underwent FBx. The study protocol contains a systematic 12-core sextant biopsy plus 2 cores per targeted lesion. One experienced urologist performed 1048 targeted biopsy cores; 467 (45%) cores were obtained using rigid processing, while the remaining 581 (55%) cores relied on elastic image processing. CsPCa was defined as International Society of Urological Pathology (ISUP) grade ≥ 2. The effect of rigid versus elastic FBx on overall and csPCa detection rates was determined. Propensity score weighting and multivariable regression models were used to account for potential biases inherent to the retrospective study design.

RESULTS

In multivariable regression analyses, age, prostate-specific antigen (PSA), and PIRADS ≥ 3 lesion were related to higher odds of finding csPCa. Elastic software-based image processing was independently associated with a higher overall PCa (odds ratio [OR] = 3.6 [2.2-6.1], p < 0.001) and csPCa (OR = 4.8 [2.6-8.8], p < 0.001) detection, respectively.

CONCLUSIONS

Contrary to existing literature, our results suggest that the robotic-driven software registration with elastic fusion might have a substantial effect on PCa detection.

Cognitive magnetic resonance imaging-ultrasound fusion transperineal targeted biopsy combined with randomized biopsy in detection of prostate cancer

BACKGROUND

Prostate cancer (PCa) is one of the most common cancers among men. Various strategies for targeted biopsy based on multiparametric magnetic resonance imaging (mp-MRI) have emerged, which may improve the accuracy of detecting clinically significant PCa in recent years.

AIM

To investigate the diagnostic efficiency of a template for cognitive MRI-ultrasound fusion transperineal targeted plus randomized biopsy in detecting PCa.

METHODS

Data from patients with an increasing prostate-specific antigen (PSA) level but less than 20 ng/mL and at least one lesion suspicious for PCa on MRI from December 2015 to June 2018 were retrospectively analyzed. All patients underwent cognitive fusion transperineal template-guided targeted biopsy followed by randomized biopsy outside the targeted area. A total of 127 patients with complete data were included in the final analysis. A multivariable logistic regression analysis was conducted, and a two-sided P < 0.05 was considered statistically significant.

RESULTS

PCa was detected in 66 of 127 patients, and 56 cases presented clinically significant PCa. Cognitive fusion targeted biopsy alone detected 59/127 cases of PCa, specifically 52/59 cases with clinically significant PCa and 7/59 cases with clinically insignificant PCa. A randomized biopsy detected seven cases of PCa negative on targeted biopsy, and four cases had clinically significant PCa. PSA density (OR: 1.008, 95%CI: 1.003-1.012, P = 0.001; OR: 1.006, 95%CI: 1.002-1.010, P = 0.004) and Prostate Imaging-Reporting and Data System (PI-RADS) scores (both P < 0.001) were independently associated with the results of cognitive fusion targeted biopsy combined with randomized biopsy and targeted biopsy alone.

CONCLUSION

This single-centered study proposed a feasible template for cognitive MRI-ultrasound fusion transperineal targeted plus randomized biopsy. Patients with higher PSAD and PI-RADS scores were more likely to be diagnosed with PCa.

Diagnostic accuracy of magnetic resonance imaging targeted biopsy techniques compared to transrectal ultrasound guided biopsy of the prostate: a systematic review and meta-analysis

Background

Multiparametric MRI localizes cancer in the prostate, allowing for MRI guided biopsy (MRI-GB) 43 alongside transrectal ultrasound-guided systematic biopsy (TRUS-GB). Three MRI-GB approaches exist; visual estimation (COG-TB); fusion software-assisted (FUS-TB) and MRI ‘in-bore’ biopsy (IB-TB). It is unknown whether any of these are superior.

We conducted a systematic review and meta-analysis to address three questions. First, whether MRI-GB is superior to TRUS-GB at detecting clinically significant PCa (csPCa). Second, whether MRI-GB is superior to TRUS-GB at avoiding detection of insignificant PCa. Third, whether any MRI-GB strategy is superior at detecting csPCa.

Methods

A systematic literature review from 2015 to 2019 was performed in accordance with the START recommendations. Studies reporting PCa detection rates, employing MRI-GB and TRUS-GB were included and evaluated using the QUADAS-2 checklist. 1553 studies were found, of which 43 were included in the meta-analysis.

Results

For csPCa, MRI-GB was superior in detection to TRUS-GB (0.83 vs. 0.63 [p = 0.02]). MRI-GB was superior in detection to TRUS-GB at avoiding detection of insignificant PCa. No MRI-GB technique was superior at detecting csPCa (IB-TB 0.87; COG TB 0.81; FUS-TB 0.81, [p = 0.55]). There was significant heterogeneity observed between the included studies.

Conclusions

In patients with suspected PCa on MRI, MRI-GB offers superior rates of csPCa detection and reduces detection of insignificant PCa compared to TRUS-GB. No individual MRI-GB technique was found to be better in csPCa detection. Prospective adequately powered randomized controlled trials are required.

Design of an Ultrasound-Navigated Prostate Cancer Biopsy System for Nationwide Implementation in Senegal

This paper presents the design of NaviPBx, an ultrasound-navigated prostate cancer biopsy system. NaviPBx is designed to support an affordable and sustainable national healthcare program in Senegal. It uses spatiotemporal navigation and multiparametric transrectal ultrasound to guide biopsies. NaviPBx integrates concepts and methods that have been independently validated previously in clinical feasibility studies and deploys them together in a practical prostate cancer biopsy system. NaviPBx is based entirely on free open-source software and will be shared as a free open-source program with no restriction on its use. NaviPBx is set to be deployed and sustained nationwide through the Senegalese Military Health Service. This paper reports on the results of the design process of NaviPBx. Our approach concentrates on "frugal technology", intended to be affordable for low-middle income (LMIC) countries. Our project promises the wide-scale application of prostate biopsy and will foster time-efficient development and programmatic implementation of ultrasound-guided diagnostic and therapeutic interventions in Senegal and beyond.

Consecutive transperineal prostatic template biopsies employing cognitive and systematic approach: a single center study

INTRODUCTION

The role of transperineal template biopsy for prostate cancer diagnosis is well established. Pre-biopsy multiparametric magnetic resonance imaging (MRI) is used in most centers for planning of prostate biopsies and staging. Cognitive and software fusion techniques are increasingly getting popular.

METHODS

We retrospectively reviewed patients who underwent transperineal template biopsies from January 2016 till December 2018. This included patients on active surveillance, previous negative transrectal ultrasonography biopsies with persistently raised prostate-specific antigen/abnormal prostate on digital rectal examination and de-novo template biopsies. Two specialist uro-radiologists reported all the scans and the biopsies were performed by one experienced urologist. The cognitive biopsies were performed for PIRADS 3-5 lesions on MRI. Total of 330 patients underwent transperineal template biopsies and cognitive target biopsies were carried out in 75 patients who were included in the study. We evaluated the results as positive/negative cognitive biopsies and also according to the PIRAD scoring. Only the patients with prostate cancer on template biopsy histology were included.

RESULTS

Fifty-seven (76%) of the cognitive biopsies were positive out of total 75.[Table: see text].

CONCLUSIONS

Combined cognitive and systematic biopsies have excellent diagnostic rate especially for PIRAD 4-5 MRI areas.

Comparison of Real-Time Virtual Sonography Navigation Versus BioJet Navigation on Magnetic Resonance Imaging-Guided Prostate Needle Biopsy: A Single Institutional Analysis

Objective: To analyze the effectiveness and complication rate of MRI-guided prostate needle biopsies by using real-time virtual sonography (RVS) vs BioJet navigation. Methods: We retrospectively reviewed 171 patients who underwent an MRI-guided prostate needle biopsy at our institution. Patients whose prostate-specific antigen level was >4.0 ng/mL and who had suspicious prostate cancer (PCa) lesions by multiparametric MRI (mpMRI) underwent 2-core MRI-guided targeted biopsy (TB) and for MRI-guided TB: RVS and BioJet. RVS navigation synchronized mpMRI images with transrectal ultrasound (TRUS) images. BioJet navigation used a software program that merged images from mpMRI and TRUS to produce a composite image. We retrospectively compared the detection rate of PCa and the frequency of severe adverse events (AEs) between these two navigation systems, focusing on patients. In addition, we compared the detection rate of MRI-guided TB cores of two navigation systems regarding anatomical position (transitional zone [TZ] or peripheral zone [PZ]). Results: Data from RVS and BioJet biopsy groups were from 65 and 106 patients, respectively. Of these, RVS-TB included 141 cores (PZ: 49 cores, TZ: 92 cores), and BioJet-TB included 276 cores (PZ: 73 cores, TZ: 203 cores). In detecting PCa, by conducting both systematic biopsy and TB, and AEs in patients, a significant difference was not noted between RVS and BioJet navigation systems. In addition, there was no significant difference in the total detection rate for PCa in TB cores between the two methods. However, in the TZ, BioJet navigation showed a significantly higher detection rate of PCa than RVS navigation (35.0% vs 17.4%, p = 0.0023) by analyzing the cores of MRI-guided TB. Conclusion: When targeting TZ lesions, BioJet navigation had a greater detection rate for PCa compared with that of RVS navigation.

[The long journey from palpation to biopsy : The history of diagnosing prostate cancer]

Though it is thousands of years old, prostate cancer (PCa) has only been known for 200 years. Until about 50 years ago, the diagnosis could only be made by digital rectal examination. Although the first prostate biopsies were already implemented in the beginning of the last century, it only obtained importance with the introduction of prostate-specific antigen (PSA) testing in the early screening for PCa and the pathologist, thus, became an essential partner for the urologist. In more recent years, specific MRI has significantly increased the accuracy of prostate biopsies. Thus, the question arises whether this technique is going to be so meaningful one day that prostate biopsy and the associated pretherapeutic histology are going to be redundant.

Comparison of clinically significant prostate cancer detection by MRI cognitive biopsy and in-bore MRI-targeted biopsy for naïve biopsy patients

Background

Multiparametric magnetic resonance imaging (mpMRI) targeted prostate biopsy increases the diagnostic accuracy of clinically significant prostate cancer (PCa). Currently there is no consensus on which type of MRI-targeted biopsy performs better in a given setting. In this study, we aimed to compare the detection rate of (clinically significant) PCa by MRI cognitive targeted biopsy (COG) and in-bore MRI-targeted biopsy (IB) techniques for naïve prostate biopsy patients in China.

Methods

Our study included 85 men from Beijing United Family Hospital and Clinics and 88 men from Beijing Hospital, National Center of Gerontology. All men had no history of prostate biopsy, undergoing mpMRI scan due to elevated PSA and/or abnormal DRE. The men in Beijing United Family Hospital group received COG plus systematic biopsy. The men in Beijing Hospital group only received IB.

Results

The median age in COG and IB group was 63.0 years and 70.0 years (P<0.01). The median PSA was 7.4 and 6.8 ng/mL in COG and IB group respectively (P=0.124). The detection rate of PCa was 36.5% by COG and 52.3% by IB (P=0.037). The detection rate of clinically significant PCa (Gleason score ≥7) was 23.5% and 29.5% by COG and IB (P=0.371) respectively. In COG group, combination biopsy (COG + systematic biopsy) achieved improved PCa (42.4%) and clinically significant PCa (28.2%) detection rate compared with COG alone. However, there was no difference in overall PCa and clinically significant PCa detection between combination biopsy and IB.

Conclusions

IB had a higher rate of overall PCa detection compared with COG, but the two approaches did not differ significantly in the detection of clinically significant PCa. There was no significant difference in detection rate of PCa and clinically significant PCa between the combination biopsy and IB.

Fusion imaging of ultrasound and MRI in the assessment of locally advanced cervical cancer: a prospective study

BACKGROUND

Fusion imaging is a new diagnostic method that integrates MRI and ultrasound. It may improve the detection and staging of locally advanced cervical cancer.

OBJECTIVE

To evaluate the feasibility and accuracy of fusion imaging in patients with locally advanced cervical cancer.

METHODS

Patients with suspicion of locally advanced cervical cancer at clinical examination and/or imaging, who were candidates for neoadjuvant treatment (chemotherapy or chemoradiation) followed by surgery, were prospectively enrolled between March and November 2018. MRI, ultrasound, and fusion images were obtained before and after neoadjuvant treatment. Feasibility, success of the fusion examination, and time needed to perform fusion studies were evaluated. The rates of concordance between MRI and ultrasound before and after performing fusion, using Cohen, Spearman, and McNemar tests were calculated. The agreement between MRI and ultrasound examination, and the agreement between radiologist and gynecologist during the fusion technique in assessing local extension of disease and the presence of residual disease after neoadjuvant therapy, were also analyzed. The rates of concordance between MRI and ultrasound examination before and after performing fusion imaging, using Cohen's kappa and Spearman's rank correlation coefficient were calculated. A McNemar test was used to assess if there were statistical significant differences in the parameters' agreement before and after performing fusion imaging.

RESULTS

40 patients were selected and of these, 33 were analyzed. A total of 52 fusion examinations were performed: 33 (63.5%) of 52 at the time of diagnosis and 19 (36.5%) of 52 after neoadjuvant treatment. Fusion imaging was feasible in 50 (96%) of 52 studies. The median overall time of fusion execution was 13 min (range 6-30) and the time spent in performing a fusion examination decreased from the first to the last examination (20 vs 6 min). The agreement between MRI and ultrasound parameters increased after performing fusion, particularly for parametrial infiltration (74% vs 86%, p=0.014 for the right posterior parametrium; 66% vs 80%, p=0.008 for the left posterior parametrium, 70% vs 82%, p=0.014 for the right lateral parametrium).

CONCLUSIONS

Fusion of MRI and ultrasound is feasible in patients with locally advanced cervical cancer and may increase the diagnostic accuracy of the single imaging methods. Fusion provides multiple diagnostic opportunities in gynecological oncology.

Fusion of ultrasound and 3D single-photon-emission computed tomography/computed tomography to identify sentinel lymph nodes in vulvar cancer: feasibility study

OBJECTIVE

To evaluate the feasibility of fusion of ultrasound imaging and three-dimensional (3D) single-photon-emission computed tomography/computed tomography (SPECT/CT) in detecting sentinel lymph nodes in women with vulvar cancer.

METHODS

This was a prospective pilot single-center study. Patients with vulvar cancer who were candidates for sentinel lymph-node biopsy were enrolled between December 2018 and February 2019. Fusion imaging virtual navigation using 3D SPECT/CT and ultrasound was performed to investigate the tumor-draining lymph node. All clinical, imaging, surgical and histological information was collected prospectively and entered into a dedicated Excel file. Feasibility and success of fusion imaging virtual navigation and time needed to perform the three steps of fusion imaging were evaluated.

RESULTS

Ten lymph-node sites were evaluated in five consecutive women with a histological diagnosis of vulvar cancer. Fusion imaging virtual navigation was feasible and completed successfully for all (10/10) draining sites. Median overall time to perform fusion imaging was 32 (range, 25-40) min and the time decreased from the first to the last examination.

CONCLUSIONS

The present study demonstrated that fusion imaging virtual navigation using 3D SPECT/CT and ultrasound is feasible and able to detect sentinel lymph nodes in women with vulvar carcinoma. Fusion imaging using ultrasound for detection of sentinel lymph nodes opens up multiple diagnostic and therapeutic opportunities in gynecological oncology. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Targeted biopsy: benefits and limitations

PURPOSE OF REVIEW

To review the current literature regarding the role of multiparametric MRI and fusion-guided biopsies in urologic practice.

RECENT FINDINGS

Fusion biopsies consistently show an increase in the detection of clinically significant cancers and decrease in low-risk disease that may be more suitable for active surveillance. Although, when to incorporate multiparametric MRI into workup is not clearly agreed upon, studies have shown a clear benefit in both biopsy naïve and those with prior negative biopsies in determining the appropriate treatment strategy. More recently, cost-analysis models have been published that show that upfront MRIs are more cost-effective when considering missed cancers and treatment courses.

SUMMARY

With improved accuracy over systematic biopsies, fusion biopsies are a superior method for detection of the true grade of cancer for both biopsy naïve and patients with prior negative biopsies, choosing appropriate candidates for active surveillance, and monitoring progression on active surveillance.

Who Can Avoid Systematic Biopsy Without Missing Clinically Significant Prostate Cancer in Men Who Undergo Magnetic Resonance Imaging-Targeted Biopsy?

BACKGROUND

The objective of the study was to identify a subset of men who can avoid systematic multisite biopsy (SyB) among those undergoing magnetic resonance imaging (MRI)-targeted transperineal 4-core biopsy (TgB) without missing clinically significant cancer (SC).

PATIENTS AND METHODS

From April 2013 to December 2017, 304 men with elevated prostate-specific antigen levels (< 20 ng/mL) or abnormal digital rectal examination and positive MRI findings underwent transrecta ultrasound and MRI-targeted transperineal 4-core with 14-core systematic biopsy. MRI findings were prospectively collected and evaluated using Prostate Imaging-Reporting and Data System version 2 (PI-RADS), and scores ≥3 were considered positive. SC was defined as Gleason score ≥3 + 4 or maximum cancer length ≥5 mm. We evaluated the diagnostic performance of TgB and SyB to detect SC and characterized men who could avoid SyB without missing SC.

RESULTS

Detection rates of any cancer and SC for TgB/SyB/their combination were 59%/63%/68% and 51%/52%/61%, respectively. TgB alone missed 14% (29/207) of any cancer and 16% (29/184) of SC detected using TgB with SyB. In uni- and multivariable analyses, PI-RADS scores of 3 to 4 were independent predictors for missing SC using TgB alone. When restricted to 81 men with PI-RADS scores of 5 (27%), SC was missed using TgB alone only in 3 (4.6% vs. 22% for the remaining 223 men; P = .007).

CONCLUSION

SC was missed using TgB alone in a non-negligible proportion of men who underwent TgB and SyB. SyB might be safely avoided in men with PI-RADS score 5 lesions with reduced risks of missing SC.

Preoperative simulation by volume rendering image and intraoperative navigation by ultrasound for posterior urethroplasty: A report of initial three cases

Introduction

In posterior urethroplasty, exposure of the proximal urethral stump is the most important step that determines surgical outcome. However, this is sometimes difficult due to deviation of the prostate or overlying scar tissue. We present a novel preoperative simulation and intraoperative navigation method for this step.

Case presentation

Three patients underwent excision and primary anastomosis for posterior urethral disruption after pelvic fracture. Preoperatively, volume‐rendering image of the posterior urethra was constructed from gadolinium‐enhanced magnetic resonance image, enabling simulation from the viewpoint of the operator in all three cases. Intraoperative navigation was performed in two patients by using transrectal ultrasound, visualizing the acoustic shadow of a cystoscope inserted into the prostatic urethra via the cystostomy tract. The overlying scar tissue was removed toward the urethral stumps identified by navigation. Urethroplasty was successful in all three patients.

Conclusion

The present methods were useful for precise identification of the proximal urethral stump.

Multiparametric MRI fusion-guided prostate biopsy in biopsy naive patients: Preliminary results from 80 patients

OBJECTIVE

The aim of this prospective study was to evaluate the early results of transrectal prostate biopsies performed under the guidance of multiparametric prostate magnetic resonance imaging (mpMRI) in biopsy naive patients.

MATERIAL AND METHODS

Biopsy naive patients who had prostate-specific antigen level 4-10 ng/mL and/or abnormal digital rectal examination findings and provided informed consent were examined using mpMRI. The study included 80 patients with an MRI-defined lesion with a Prostate Imaging and Reporting and Data System (PIRADS) score of ≥3. All mpMRIs were reported by the same uro-radiologist according to PIRADS version 2. An MRI-targeted biopsy was performed by an ultrasonography system with rigid fusion registration software. The first two to five core biopsies per MRI-defined lesions were obtained, and then a standard random 12-core biopsy was performed. Transrectal biopsies were performed under local anesthesia or sedoanalgesia.

RESULTS

Of the 80 patients, 29 (36.3%) were found to have cancer using the conventional 12-core biopsy, but only 20 (25%) were found to have prostate cancer using the MRI-targeted prostate biopsy. Combining the two biopsy methods (conventional+MRI-targeted), cancer detection rate increased to 43.8% (35/80 patients). The cancer detection rate using the combined method was statistically higher than that using the conventional biopsy method (p=0.03). Using the conventional biopsy method, 960 core biopsies were collected from 80 patients. Of the 960 core biopsies, 111 (11.6%) were found to be cancer. Further, 101 suspected lesions were detected using mpMRI in 80 patients. In addition, 397 core biopsies were obtained from these lesions. Of the 397 core biopsies, 62 (15.6%) were reported as prostate cancer. The core positivity rate of MR-targeted biopsy was statistically higher than that of conventional biopsy (p=0.04).

CONCLUSION

The preliminary results of MRI-targeted prostate biopsy combined with conventional biopsy suggested that the combined biopsy method was crucial in prostate cancer diagnosis especially in patients with prostate cancer suspicion and no biopsy history. However, larger sample prospective studies are needed to validate the effectiveness of MRI-targeted biopsy and combined biopsy methods.

Beyond transrectal ultrasound-guided prostate biopsies: available techniques and approaches

OBJECTIVES

Recent advances have led to the use of magnetic resonance imaging (MRI) alone or with fusion to transrectal ultrasound (TRUS) images for guiding biopsy of the prostate. Our group sought to develop consensus recommendations regarding MRI-guided prostate biopsy based on currently available literature and expert opinion.

METHODS

The published literature on the subject of MRI-guided prostate biopsy was reviewed using standard search terms and synthesized and analyzed by four different subgroups from among the authors. The literature was grouped into four categories-MRI-guided biopsy platforms, robotic MRI-TRUS fusion biopsy, template mapping biopsy and transrectal MRI-TRUS fusion biopsy. Consensus recommendations were developed using the Oxford Center for Evidence Based Medicine criteria.

RESULTS

There is limited high level evidence available on the subject of MRI-guided prostate biopsy. MRI guidance with or without TRUS fusion can lead to fewer unnecessary biopsies, help identify high-risk (Gleason ≥ 3 + 4) cancers that might have been missed on standard TRUS biopsy and identify cancers in the anterior prostate. There is no apparent significant difference between MRI biopsy platforms. Template mapping biopsy is perhaps the most accurate method of assessing volume and grade of tumor but is accompanied by higher incidence of side effects compared to TRUS biopsy.

CONCLUSIONS

Magnetic resonance imaging-guided biopsies are feasible and better than traditional ultrasound-guided biopsies for detecting high-risk prostate cancer and anterior lesions. Judicious use of MRI-guided biopsy could enhance diagnosis of clinically significant prostate cancer while limiting diagnosis of insignificant cancer.

Cancer detection rate of prebiopsy MRI with subsequent systematic and targeted biopsy are superior to non-targeting systematic biopsy without MRI in biopsy naïve patients: a retrospective cohort study

Background

To determine whether prebiopsy multiparametric magnetic resonance imaging (mpMRI) with subsequent systematic plus targeted biopsies for suspicious lesions improve prostate cancer detection compared with standard non-targeting systematic biopsies without mpMRI in biopsy-naïve patients.

Methods

Patients who underwent their first prostate biopsy due to suspicion of prostate cancer were analyzed retrospectively to compare the biopsy outcomes between patients who received prebiopsy mpMRI (215 patients) and those who did not (281 patients). mpMRI was performed to determine pre-biopsy likelihood of the presence of prostate cancer using a three-point scale (1 = low level of suspicion, 2 = equivocal, and 3 = high level of suspicion). Systematic biopsies were performed in both groups. Targeted biopsies were added for a high level of suspicious lesions on mpMRI. All biopsies were performed by transperineal biopsy technique. After biopsy, Prostate Imaging Reporting and Data System ver. 2 (PIRADS-2) scoring was performed to describe the mpMRI findings and predictive value of PIRADS-2 was evaluated.

Results

The detection rate of total and clinically significant prostate cancer was significantly higher in patients who received prebiopsy mpMRI than in those who did not (55.3 and 46.0% vs. 42.0 and 35.2%, respectively; p = 0.004 and p = 0.016). The clinically insignificant prostate cancer detection rate was similar between the two groups (9.3% vs. 6.8%; p = 0.32). Of 86 patients who underwent systematic plus targeted biopsy in the MRI cohort and were diagnosed with prostate cancer, seven patients were detected by addition of targeted biopsy whereas 29 patients were missed by targeted biopsy but detected by systematic biopsy. There was a correlation between the PIRADS-2 and prostate cancer detection rate, and a receiver-operator curve analysis yielded an area under the curve of 0.801 (p <  0.0001).

Conclusions

Prebiopsy mpMRI with subsequent systematic plus targeted biopsies for suspicious lesions can yield a higher cancer detection rate than non-targeting systematic biopsies. PIRADS-2 scoring is useful for predicting the biopsy outcome.

"Super-active surveillance": MRI ultrasound fusion biopsy and ablation for less invasive management of prostate cancer

Multiparametric magnetic resonance imaging (mpMRI) of the prostate has allowed clinicians to better visualize and target suspicious lesions during biopsy. Targeted prostate biopsies give a more accurate representation of the true cancer volume and stage so that appropriate treatment or active surveillance can be selected. Advances in technology have led to the development of MRI and ultrasound fusion platforms used for targeted biopsies, monitoring cancer progression, and more recently for the application of focal therapy. Lesions visualized on mpMRI can be targeted for ablation with a variety of energy sources employed under both local and general anesthesia. Focal ablation may offer an alternative option for treating prostate cancer as compared to the well-established interventions of whole-gland radiation or prostatectomy. Focal ablation may also be an option for patients on active surveillance who wish to be even more "active" in their surveillance. In this review, we describe the advancements and development of fusion biopsies, the rationale behind focal therapy, and introduce focal ablative techniques for indolent prostate cancers ("super-active surveillance"), including cryoablation and focal laser ablation (FLA) and the subsequent MRI/biopsy surveillance.

A prospective study of magnetic resonance imaging and ultrasonography (MRI/US)-fusion targeted biopsy and concurrent systematic transperineal biopsy with the average of 18-cores to detect clinically significant prostate cancer

Background

This study compared the detection rates for clinically significant prostate cancer (CSPC) between magnetic resonance imaging and ultrasonography (MRI/US)-fusion-targeted biopsy (TB), systematic biopsy (SB) and combination of TB and SB.

Methods

This prospective study evaluated simultaneous TB and SB for consecutive patients with suspicious lesions that were detected using pre-biopsy multiparametric MRI. A commercially available real-time virtual sonography system was used to perform the MRI/US-fusion TB with the transperineal technique. The prostate imaging reporting and data system version 2 (PI-RADS v2) was assigned to categorize the suspicious lesions.

Results

A total of 177 patients were included in this study. The detection rate for CSPC was higher using SB, compared to TB (57.1% vs 48.0%, p = 0.0886). The detection rate for CSPC was higher using the combination of TB and SB, compared to only SB (63.3% vs 57.1%, p = 0.2324). Multivariate analysis revealed that PIRADS v2 category 4 and an age of <65 years were independent predictors for TB upgrading (vs. the SB result).

Conclusions

PI-RADS v2 category 4 and an age of <65 years were predictive factors of upgrading the Gleason score by MRI/US-fusion TB. Thus, MRI/US-fusion TB may be appropriate for patients with those characteristics.

Trial registration

This study was retrospectively registered at the University Hospital Medical Information Network (UMINID000025911) in Jan 30, 2017.

[MRI/TRUS fusion-guided prostate biopsy : Value in the context of focal therapy]

BACKGROUND

Several systems for MRI/TRUS fusion-guided biopsy of the prostate are commercially available. Many studies have shown superiority of fusion systems for tumor detection and diagnostic quality compared to random biopsy. The benefit of fusion systems in focal therapy of prostate cancer (PC) is less clear.

OBJECTIVES

Critical considerations of fusion systems for planning and monitoring of focal therapy of PC were investigated.

MATERIALS AND METHODS

A systematic literature review of available fusion systems for the period 2013-5/2016 was performed. A checklist of technical details, suitability for special anatomic situations and suitability for focal therapy was established by the German working group for focal therapy (Arbeitskreis fokale und Mikrotherapie).

RESULTS

Eight fusion systems were considered (Artemis™, BioJet, BiopSee®, iSR´obot™ Mona Lisa, Hitachi HI-RVS, UroNav and Urostation®). Differences were found for biopsy mode (transrectal, perineal, both), fusion mode (elastic or rigid), navigation (image-based, electromagnetic sensor-based or mechanical sensor-based) and space requirements.

DISCUSSION

Several consensus groups recommend fusion systems for focal therapy. Useful features are "needle tracking" and compatibility between fusion system and treatment device (available for Artemis™, BiopSee® and Urostation® with Focal One®; BiopSee®, Hitachi HI-RVS with NanoKnife®; BioJet, BiopSee® with cryoablation, brachytherapy).

CONCLUSIONS

There are a few studies for treatment planning. However, studies on treatment monitoring after focal therapy are missing.

Assessment of free-hand transperineal targeted prostate biopsy using multiparametric magnetic resonance imaging-transrectal ultrasound fusion in Chinese men with prior negative biopsy and elevated prostate-specific antigen

BACKGROUND

To evaluate the role of free-hand transperineal targeted prostate biopsy using multiparametric magnetic resonance imaging-transrectal ultrasound (mpMRI-TRUS) fusion in Chinese men with repeated biopsy.

METHODS

A total of 101 consecutive patients suspicious of prostate cancer (PCa) at the mpMRI scan and with prior negative biopsy and elevated PSA values were prospectively recruited at two urological centers. Suspicious areas on mpMRI were defined and graded using PI-RADS score. Targeted biopsies (TB) were performed for each suspicious lesion and followed a 12-core systematic biopsy (SB). Results of biopsy pathology and whole-gland pathology at prostatectomy were analyzed and compared between TB and SB. The risk for biopsy positivity was assessed by univariate and multivariate logistic regression analysis.

RESULTS

Fusion biopsy revealed PCa in 41 of 101 men (40.6%) and 25 (24.8%) were clinically significant. There was exact agreement between TB and SB in 74 (73.3%) men. TB diagnosed 36% more significant cancer than SB (22 vs 13 cases, P = 0.012). When TB were combined with SB, an additional 14 cases (34.1%) of mostly significant PCa (71.4%) were diagnosed (P = 0.036). TB had greater sensitivity and accuracy for significant cancer than SB in 26 men with whole-gland pathology after prostatectomy. PI-RADS score on mpMRI was the most powerful predictor of PCa and significant cancer.

CONCLUSIONS

Free-hand transperineal TB guided with MRI-TRUS fusion imaging improves detection of clinical significant PCa in Chinese men with previously negative biopsy. PI-RADS score is a reliable predictor of PCa and significant cancer.

Transperineal ultrasound-guided prostate biopsy is safe even when patients are on combination antiplatelet and/or anticoagulation therapy

Background

To assess whether hemorrhagic complications associated with transperineal prostate biopsy increased in patients on antiplatelet and/or anticoagulant therapy.

Methods

In total, 598 consecutive patients underwent transperineal prostate biopsy. The medication group comprised patients who took anti-thromboembolic agents, and the control group comprised those who did not take these agents. No anti-thromboembolic agent was stopped before, during, or after prostate biopsy in the medication group. Complications developing in both groups were compared and classified using the modified Clavien classification system. Subgroup analyses to compare complications in patients taking single antiplatelet, single anticoagulant, and dual antiplatelet and/or anticoagulant agents, and multivariate analyses to predict bleeding risk were also performed.

Results

Of the 598 eligible patients, 149 comprised the medication group and 449 comprised the control group. Hematuria (Grade I) developed in 88 (59.1%) and 236 (52.5%) patients in the medication and control group, respectively (p = 0.18). Clot retention (Grade I) was more frequently observed in the medication group than the controls (2.0% versus 0.2%, respectively, p < 0.05). Hospitalization was more frequently prolonged in the medication than the control group (4.0% versus 0.4% of patients, respectively). No complication of Grade III or higher developed in either group. Hematuria was more frequent in patients taking a single anticoagulant (p = 0.007) or two anti-thromboembolic agents (p = 0.04) compared with those taking a single antiplatelet agent. Other complications were generally similar among the groups. In the multivariate analysis, taking more than two anti-thromboembolic agents was the only significant risk factor for bleeding events.

Conclusion

No severe complication developed after the transperineal biopsies in either group, although minor bleeding was somewhat more frequent in the medication group. It may not be necessary to discontinue anticoagulant and/or antiplatelet agents when transperineal prostate biopsy is contemplated.

A critical comparison of techniques for MRI-targeted biopsy of the prostate

MRI-targeted biopsy is a promising technique that offers an improved detection of clinically significant prostate cancer over standard non-targeted biopsy. It is established that prostate MRI is of use in both the primary and repeat biopsy setting for the detection of significant prostate cancer. There are three approaches to targeting biopsies to areas of interest seen on prostate MRI. They each rely on the acquisition and reporting of a diagnostic quality multi-parametric MRI scan used to identify areas of interest, and the subsequent use of those diagnostic quality images in combination with real-time images of the prostate during the biopsy procedure. The three techniques are: visual registration of the MRI images with a real-time ultrasound image; software-assisted fusion of the MRI images and the real-time ultrasound images, and in-bore biopsy, which requires registration of a diagnostic quality MRI scan with a real time interventional MRI image. In this paper we compare the three techniques and evaluate those studies where there is a direct comparison of more than one MRI-targeting technique. PubMed was searched from inception to November 2016 using the search terms (cognitive registration OR visual registration OR fusion biopsy OR in-bore biopsy OR targeted biopsy) AND (prostate cancer OR prostate adenocarcinoma OR prostate carcinoma OR prostatic carcinoma OR prostatic adenocarcinoma) AND (MRI OR NMR OR magnetic resonance imaging OR mpMRI OR multiparametric MRI). The initial search included 731 abstracts. Eleven full text papers directly compared two or more techniques of MRI-targeting, and were selected for inclusion. The detection of clinically significant prostate cancer varied from 0% to 93.3% for visual registration, 23.2% to 100% for software-assisted registration and 29% to 80% for in-bore biopsy. Detection rates for clinically significant cancer are dependent on the prevalence of cancer within the population biopsied, which in turn is determined by the selection criteria [biopsy naïve, previous negative biopsy, prostate specific antigen (PSA) selection criteria, presence of a lesion on MRI]. Cancer detection rates varied more between study populations than between biopsy approaches. Currently there is no consensus on which type of MRI-targeted biopsy performs better in a given setting. Although there have been studies supporting each of the three techniques, substantial differences in methodology and reporting the findings make it difficult to reliably compare their outcomes.

Multiparametric MRI in the Detection of Clinically Significant Prostate Cancer

Prostate cancer is the most common cancer among men aged 50 years and older in developed countries and the third leading cause of cancer-related death in men. Multiparametric prostate MR imaging is currently the most accurate imaging modality to detect, localize, and stage prostate cancer. The role of multi-parametric MR imaging in the detection of clinically significant prostate cancer are discussed. In addition, insights are provided in imaging techniques, protocol, and interpretation.

Precision of MRI/ultrasound-fusion biopsy in prostate cancer diagnosis: an ex vivo comparison of alternative biopsy techniques on prostate phantoms

PURPOSE

Comparing the accuracy of MRI/ultrasound-guided target-biopsy by transrectal biopsy (TRB) with elastic versus rigid image fusion versus transperineal biopsy (TPB) with rigid image fusion in a standardized setting.

METHODS

Target-biopsy of six differently sized and located lesions was performed on customized CIRS 070L prostate phantoms. Lesions were only MRI-visible. After prior MRI for lesion location, one targeted biopsy per lesion was obtained by TRB with elastic image fusion with Artemis™ (Eigen, USA), TRB with rigid image fusion with real-time virtual sonography (Hitachi, Japan) and TPB with rigid image fusion with a brachytherapy approach (Elekta, Sweden), each on a phantom of 50, 100 and 150 ml prostate volume. The needle trajectories were marked by contrast agent and detected in a postinterventional MRI.

RESULTS

Overall target detection rate was 79.6% with a slight superiority for the TPB (83.3 vs. 77.8 vs. 77.8%). TRB with elastic image fusion showed the highest overall precision [median distance to lesion center 2.37 mm (0.14-4.18 mm)], independent of prostate volume. Anterior lesions were significantly more precisely hit than transitional and basal lesions (p = 0.034; p = 0.015) with comparable accuracy for TRB with elastic image fusion and TPB. In general, TRB with rigid image fusion was inferior [median 3.15 mm (0.37-10.62 mm)], particularly in small lesions.

CONCLUSION

All biopsy techniques allow detection of clinically significant tumors with a median error of 2-3 mm. Elastic image fusion appears to be the most precise technique, independent of prostate volume, target size or location.

Magnetic Resonance Imaging-Ultrasound Fusion-Guided Prostate Biopsy: Review of Technology, Techniques, and Outcomes

Transrectal ultrasound (TRUS)-guided (12-14 core) systematic biopsy of the prostate is the recommended standard for patients with suspicion of prostate cancer (PCa). Advances in imaging have led to the application of magnetic resonance imaging (MRI) for the detection of PCa with subsequent development of software-based co-registration allowing for the integration of MRI with real-time TRUS during prostate biopsy. A number of fusion-guided methods and platforms are now commercially available with common elements in image and analysis and planning. Implementation of fusion-guided prostate biopsy has now been proven to improve the detection of clinically significant PCa in appropriately selected patients.

Comparing Three Different Techniques for Magnetic Resonance Imaging-targeted Prostate Biopsies: A Systematic Review of In-bore versus Magnetic Resonance Imaging-transrectal Ultrasound fusion versus Cognitive Registration. Is There a Preferred Technique?

CONTEXT

The introduction of magnetic resonance imaging-guided biopsies (MRI-GB) has changed the paradigm concerning prostate biopsies. Three techniques of MRI-GB are available: (1) in-bore MRI target biopsy (MRI-TB), (2) MRI-transrectal ultrasound fusion (FUS-TB), and (3) cognitive registration (COG-TB).

OBJECTIVE

To evaluate whether MRI-GB has increased detection rates of (clinically significant) prostate cancer (PCa) compared with transrectal ultrasound-guided biopsy (TRUS-GB) in patients at risk for PCa, and which technique of MRI-GB has the highest detection rate of (clinically significant) PCa.

EVIDENCE ACQUISITION

We performed a literature search in PubMed, Embase, and CENTRAL databases. Studies were evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 checklist and START recommendations. The initial search identified 2562 studies and 43 were included in the meta-analysis.

EVIDENCE SYNTHESIS

Among the included studies 11 used MRI-TB, 17 used FUS-TB, 11 used COG-TB, and four used a combination of techniques. In 34 studies concurrent TRUS-GB was performed. There was no significant difference between MRI-GB (all techniques combined) and TRUS-GB for overall PCa detection (relative risk [RR] 0.97 [0.90-1.07]). MRI-GB had higher detection rates of clinically significant PCa (csPCa) compared with TRUS-GB (RR 1.16 [1.02-1.32]), and a lower yield of insignificant PCa (RR 0.47 [0.35-0.63]). There was a significant advantage (p = 0.02) of MRI-TB compared with COG-TB for overall PCa detection. For overall PCa detection there was no significant advantage of MRI-TB compared with FUS-TB (p=0.13), and neither for FUS-TB compared with COG-TB (p=0.11). For csPCa detection there was no significant advantage of any one technique of MRI-GB. The impact of lesion characteristics such as size and localisation could not be assessed.

CONCLUSIONS

MRI-GB had similar overall PCa detection rates compared with TRUS-GB, increased rates of csPCa, and decreased rates of insignificant PCa. MRI-TB has a superior overall PCa detection compared with COG-TB. FUS-TB and MRI-TB appear to have similar detection rates. Head-to-head comparisons of MRI-GB techniques are limited and are needed to confirm our findings.

PATIENT SUMMARY

Our review shows that magnetic resonance imaging-guided biopsy detects more clinically significant prostate cancer (PCa) and less insignificant PCa compared with systematic biopsy in men at risk for PCa.

Elastic Versus Rigid Image Registration in Magnetic Resonance Imaging-transrectal Ultrasound Fusion Prostate Biopsy: A Systematic Review and Meta-analysis

CONTEXT

The main difference between the available magnetic resonance imaging-transrectal ultrasound (MRI-TRUS) fusion platforms for prostate biopsy is the method of image registration being either rigid or elastic. As elastic registration compensates for possible deformation caused by the introduction of an ultrasound probe for example, it is expected that it would perform better than rigid registration.

OBJECTIVE

The aim of this meta-analysis is to compare rigid with elastic registration by calculating the detection odds ratio (OR) for both subgroups. The detection OR is defined as the ratio of the odds of detecting clinically significant prostate cancer (csPCa) by MRI-TRUS fusion biopsy compared with systematic TRUS biopsy. Secondary objectives were the OR for any PCa and the OR after pooling both registration techniques.

EVIDENCE ACQUISITION

The electronic databases PubMed, Embase, and Cochrane were systematically searched for relevant studies according to the Preferred Reporting Items for Systematic Review and Meta-analysis Statement. Studies comparing MRI-TRUS fusion and systematic TRUS-guided biopsies in the same patient were included. The quality assessment of included studies was performed using the Quality Assessment of Diagnostic Accuracy Studies version 2.

EVIDENCE SYNTHESIS

Eleven papers describing elastic and 10 describing rigid registration were included. Meta-analysis showed an OR of csPCa for elastic and rigid registration of 1.45 (95% confidence interval [CI]: 1.21-1.73, p<0.0001) and 1.40 (95% CI: 1.13-1.75, p=0.002), respectively. No significant difference was seen between the subgroups (p=0.83). Pooling subgroups resulted in an OR of 1.43 (95% CI: 1.25-1.63, p<0.00001).

CONCLUSIONS

No significant difference was identified between rigid and elastic registration for MRI-TRUS fusion-guided biopsy in the detection of csPCa; however, both techniques detected more csPCa than TRUS-guided biopsy alone.

PATIENT SUMMARY

We did not identify any significant differences in prostate cancer detection between two distinct magnetic resonance imaging-transrectal ultrasound fusion systems which vary in their method of compensating for prostate deformation.

Magnetic resonance imaging - ultrasound fusion targeted biopsy outperforms standard approaches in detecting prostate cancer: A meta-analysis

The aim of the present study was to determine whether magnetic resonance imaging - ultrasound (MRI-US) fusion prostate biopsy is superior to systematic biopsy for making a definitive diagnosis of prostate cancer. The two strategies were also compared regarding their ability to detect clinically significant and insignificant prostate cancer. A literature search was conducted through the PubMed, EMBASE and China National Knowledge Infrastructure databases using appropriate search terms. A total of 3,415 cases from 21 studies were included in the present meta-analysis. Data were expressed as relative risk (RR) and 95% confidence interval. The results revealed that MRI-US fusion biopsy achieved a higher rate of overall prostate cancer detection compared with systematic biopsy (RR=1.09; P=0.047). Moreover, MRI-US fusion biopsy detected more clinically significant cancers compared with systematic biopsy (RR=1.22; P<0.01). It is therefore recommended that multi-parametric MRI-US is performed in men suspected of having prostate cancer to optimize the detection of clinically significant disease, while reducing the burden of biopsies.

A practical approach to investigating a man with a raised prostate-specific antigen in the modern era

Urologists in the UK are encouraged to follow the National Institute for Health and Care Excellence (NICE) guidelines for patient management. In 2014, members of the British Association of Urological Surgeons (BAUS) were asked in a survey what diagnostic pathway they would follow for themselves or their relatives if they had a raised prostate-specific antigen (PSA). It was found that only a quarter would follow NICE guidance. The current recommendations rely on pathological assessment of prostate tissue obtained at a transrectal ultrasound guided biopsy. Increasing evidence indicates that pre-biopsy multiparametric magnetic resonance imaging (mp-MRI) coupled with targeted biopsy approaches outperform random biopsies in the detection of clinically significant disease. Herein we discuss the role of magnetic resonance imaging and targeted biopsy approaches to diagnose prostate cancer in the modern era.

Accuracy and agreement of PIRADSv2 for prostate cancer mpMRI: A multireader study

PURPOSE

Multiparametric MRI (mpMRI) improves the detection of clinically significant prostate cancer, but is limited by interobserver variation. The second version of theProstate Imaging Reporting and Data System (PIRADSv2) was recently proposed as a standard for interpreting mpMRI. To assess the performance and interobserver agreement of PIRADSv2 we performed a multi-reader study with five radiologists of varying experience.

MATERIALS AND METHODS

Five radiologists (n = 2 prostate dedicated, n = 3 general body) blinded to clinicopathologic results detected and scored lesions on prostate mpMRI using PIRADSv2. The endorectal coil 3 Tesla MRI included T2W, diffusion-weighted imaging (apparent diffusion coefficient, b2000), and dynamic contrast enhancement. Thirty-four consecutive patients were included. Results were correlated with radical prostatectomy whole-mount histopathology produced with patient-specific three-dimensional molds. An index lesion was defined on pathology as the lesion with highest Gleason score or largest volume if equivalent grades. Average sensitivity and positive predictive values (PPVs) for all lesions and index lesions were determined using generalized estimating equations. Interobserver agreement was evaluated using index of specific agreement.

RESULTS

Average sensitivity was 91% for detecting index lesions and 63% for all lesions across all readers. PPV was 85% for PIRADS ≥ 3 and 90% for PIRADS ≥ 4. Specialists performed better only for PIRADS ≥ 4 with sensitivity 90% versus 79% (P = 0.01) for index lesions. Index of specific agreement among readers was 93% for the detection of index lesions, 74% for the detection of all lesions, and 85% for scoring index lesions, and 58% for scoring all lesions.

CONCLUSION

By using PIRADSv2, general body radiologists and prostate specialists can detect high-grade index prostate cancer lesions with high sensitivity and agreement.

LEVEL OF EVIDENCE

1 J. Magn. Reson. Imaging 2017;45:579-585.

Multiparametric Magnetic Resonance Imaging in the Diagnosis of Prostate Cancer: A Systematic Review

A systematic review was conducted to investigate the use of multiparametric magnetic resonance imaging (MPMRI) followed by targeted biopsy in the diagnosis of clinically significant prostate cancer (CSPC) and to compare it with transrectal ultrasound-guided (TRUS-guided) systematic biopsy in patients with an elevated risk of prostate cancer who are either biopsy-naive or who have a previous negative TRUS-guided biopsy. MEDLINE, PubMed and EMBASE (1997 to April 2014), the Cochrane Library and six relevant conferences were searched to find eligible studies. Search terms indicative of 'prostate cancer' and 'magnetic resonance imaging' with their alternatives were used. Twelve systematic reviews, 52 full texts and 28 abstracts met the preplanned study selection criteria; data from 15 articles were extracted. In patients with an elevated risk of prostate cancer who were biopsy-naive, MPMRI followed by targeted biopsy could detect 2-13% of CSPC patients whom TRUS-guided systematic biopsy missed; TRUS-guided systematic biopsy could detect 0-7% of CSPC patients whom MPMRI followed by targeted biopsy missed. In patients with an elevated risk of prostate cancer who had a previous negative TRUS-guided biopsy, MPMRI followed by targeted biopsy detected more CSPC patients than repeated TRUS-guided systematic biopsy in all four studies, with a total of 516 patients, but only one study reached a statistically significant difference. In patients with an elevated risk of prostate cancer who are biopsy-naive, there is insufficient evidence for MPMRI followed by targeted biopsy to be considered the standard of care. In patients who had a prior negative TRUS-guided systematic biopsy and show a growing risk of having CSPC, MPMRI followed by targeted biopsy may be helpful to detect more CSPC cases as opposed to a repeat TRUS-guided systematic biopsy.

Biomechanical modeling constrained surface-based image registration for prostate MR guided TRUS biopsy

PURPOSE

Adding magnetic resonance (MR)-derived information to standard transrectal ultrasound (TRUS) images for guiding prostate biopsy is of substantial clinical interest. A tumor visible on MR images can be projected on ultrasound (US) by using MR-US registration. A common approach is to use surface-based registration. The authors hypothesize that biomechanical modeling will better control deformation inside the prostate than a regular nonrigid surface-based registration method. The authors developed a novel method by extending a nonrigid surface-based registration algorithm with biomechanical finite element (FE) modeling to better predict internal deformations of the prostate.

METHODS

Data were collected from ten patients and the MR and TRUS images were rigidly registered to anatomically align prostate orientations. The prostate was manually segmented in both images and corresponding surface meshes were generated. Next, a tetrahedral volume mesh was generated from the MR image. Prostate deformations due to the TRUS probe were simulated using the surface displacements as the boundary condition. A three-dimensional thin-plate spline deformation field was calculated by registering the mesh vertices. The target registration errors (TREs) of 35 reference landmarks determined by surface and volume mesh registrations were compared.

RESULTS

The median TRE of a surface-based registration with biomechanical regularization was 2.76 (0.81-7.96) mm. This was significantly different than the median TRE of 3.47 (1.05-7.80) mm for regular surface-based registration without biomechanical regularization.

CONCLUSIONS

Biomechanical FE modeling has the potential to improve the accuracy of multimodal prostate registration when comparing it to a regular nonrigid surface-based registration algorithm and can help to improve the effectiveness of MR guided TRUS biopsy procedures.

Targeted prostate biopsy: value of multiparametric magnetic resonance imaging in detection of localized cancer

Prostate cancer is the second most common cancer in men, with 1.1 million new cases worldwide reported by the World Health Organization in one recent year. Transrectal ultrasound (TRUS)-guided biopsy has been used for the diagnosis of prostate cancer for over 2 decades, but the technique is usually blind to cancer location. Moreover, the false negative rate of TRUS biopsy has been reported to be as high as 47%. Multiparametric magnetic resonance imaging (mp-MRI) includes T1- and T2-weighted imaging as well as dynamic contrast-enhanced (DCE) and diffusion-weighted imaging (DWI). mp-MRI is a major advance in the imaging of prostate cancer, enabling targeted biopsy of suspicious lesions. Evolving targeted biopsy techniques-including direct in-bore biopsy, cognitive fusion and software-based MRI-ultrasound (MRI-US) fusion-have led to a several-fold improvement in cancer detection compared to the earlier method. Importantly, the detection of clinically significant cancers has been greatly facilitated by targeting, compared to systematic biopsy alone. Targeted biopsy via MRI-US fusion may dramatically alter the way prostate cancer is diagnosed and managed.

Recent advances in image-guided targeted prostate biopsy

Prostate cancer is a common malignancy in the United States that results in over 30,000 deaths per year. The current state of prostate cancer diagnosis, based on PSA screening and sextant biopsy, has been criticized for both overdiagnosis of low-grade tumors and underdiagnosis of clinically significant prostate cancers (Gleason score ≥7). Recently, image guidance has been added to perform targeted biopsies of lesions detected on multi-parametric magnetic resonance imaging (mpMRI) scans. These methods have improved the ability to detect clinically significant cancer, while reducing the diagnosis of low-grade tumors. Several approaches have been explored to improve the accuracy of image-guided targeted prostate biopsy, including in-bore MRI-guided, cognitive fusion, and MRI/transrectal ultrasound fusion-guided biopsy. This review will examine recent advances in these image-guided targeted prostate biopsy techniques.

Magnetic Resonance-Guided Prostate Biopsy

The optimal strategy for prostate cancer diagnosis is to avoid overdiagnosis, defined as diagnosis of clinically insignificant disease, and undersampling of the gland, which leads to missing clinically significant disease. Targeted prostate biopsy is a potential solution for decreasing the rate of both overdiagnosis and undersampling of prostate cancer. We focus here on different techniques for targeting prostate lesions identified on multiparametric MR imaging and review different clinical settings in which MR imaging-targeted prostate biopsies are performed.