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

Medical image computing and computer-aided medical interventions applied to soft tissues. Work in progress in urology

Until recently, Computer-Aided Medical Interventions (CAMI) and Medical Robotics have focused on rigid and non deformable anatomical structures. Nowadays, special attention is paid to soft tissues, raising complex issues due to their mobility and deformation. Mini-invasive digestive surgery was probably one of the first fields where soft tissues were handled through the development of simulators, tracking of anatomical structures and specific assistance robots. However, other clinical domains, for instance urology, are concerned. Indeed, laparoscopic surgery, new tumour destruction techniques (e.g. HIFU, radiofrequency, or cryoablation), increasingly early detection of cancer, and use of interventional and diagnostic imaging modalities, recently opened new challenges to the urologist and scientists involved in CAMI. This resulted in the last five years in a very significant increase of research and developments of computer-aided urology systems. In this paper, we propose a description of the main problems related to computer-aided diagnostic and therapy of soft tissues and give a survey of the different types of assistance offered to the urologist: robotization, image fusion, surgical navigation. Both research projects and operational industrial systems are discussed

Accuracy of multiparametric magnetic resonance imaging to detect significant prostate cancer and index lesion location

Background: Multiparametric magnetic resonance imaging (mpMRI) of the prostate appears to improve prostate cancer detection, but studies comparing mpMRI to histopathology at the time of radical prostatectomy (RP) are lacking. This retrospective study determined the accuracy of mpMRI predicting Gleason score and index lesion location at the time of RP, the current gold standard for diagnosis. Methods: Between April 2013 and April 2016, a database of all men aged more than 40 years who underwent RP after positive transrectal ultrasound biopsy by an experienced urological surgeon was collated at a single regional centre. This was cross‐referenced with a database of all men who had mpMRIs performed at a single centre and reported according to Prostate Imaging Reporting and Data System (PI‐RADS version 1) during this period to generate a sample size of 64 men. A Spearman\u27s rho test was utilized to calculate correlation. Results: Median age of patients was 64 years, the median prostate‐specific antigen at RP was 6.22 ng/mL. mpMRI was positive (≥PI‐RADS 3) in 85.9% of patients who underwent RP. More than 92% of participants had Gleason ≥7 disease. A positive relationship between mpMRI prostate PI‐RADS score and RP cancer volume was demonstrated. An anatomical location correlation calculated in octants was found to be 89.1% accurate. Conclusion: mpMRI accurately detects prostate cancer location and severity when compared with gold standard histopathology at the time of RP. It thus has an important role in planning for future prostate biopsy and cancer treatment

The primacy of multiparametric MRI in men with suspected prostate cancer

Background: Multiparametric MRI (mpMRI) became recognised in investigating those with suspected prostate cancer between 2010 and 2012; in the USA, the preventative task force moratorium on PSA screening was a strong catalyst. In a few short years, it has been adopted into daily urological and oncological practice. The pace of clinical uptake, born along by countless papers proclaiming high accuracy in detecting clinically significant prostate cancer, has sparked much debate about the timing of mpMRI within the traditional biopsy-driven clinical pathways. There are strongly held opposing views on using mpMRI as a triage test regarding the need for biopsy and/or guiding the biopsy pattern. Objective: To review the evidence base and present a position paper on the role of mpMRI in the diagnosis and management of prostate cancer. Methods: A subgroup of experts from the ESUR Prostate MRI Working Group conducted literature review and face to face and electronic exchanges to draw up a position statement. Results: This paper considers diagnostic strategies for clinically significant prostate cancer; current national and international guidance; the impact of pre-biopsy mpMRI in detection of clinically significant and clinically insignificant neoplasms; the impact of pre-biopsy mpMRI on biopsy strategies and targeting; the notion of mpMRI within a wider risk evaluation on a patient by patient basis; the problems that beset mpMRI including inter-observer variability. Conclusions: The paper concludes with a set of suggestions for using mpMRI to influence who to biopsy and who not to biopsy at diagnosis. Key Points: • Adopt mpMRI as the first, and primary, investigation in the workup of men with suspected prostate cancer. • PI-RADS assessment categories 1 and 2 have a high negative predictive value in excluding significant disease, and systematic biopsy may be postponed, especially in men with low-risk of disease following additional risk stratification. • PI-RADS assessment category lesions 4 and 5 should be targeted; PI-RADS assessment category lesion 3 may be biopsied as a target, as part of systematic biopsies or may be observed depending on risk stratification

MRI-targeted or standard biopsy for prostate-cancer diagnosis

Background Multiparametric magnetic resonance imaging (MRI), with or without targeted biopsy, is an alternative to standard transrectal ultrasonography-guided biopsy for prostate-cancer detection in men with a raised prostate-specific antigen level who have not undergone biopsy. However, comparative evidence is limited. Methods In a multicenter, randomized, noninferiority trial, we assigned men with a clinical suspicion of prostate cancer who had not undergone biopsy previously to undergo MRI, with or without targeted biopsy, or standard transrectal ultrasonography-guided biopsy. Men in the MRI-targeted biopsy group underwent a targeted biopsy (without standard biopsy cores) if the MRI was suggestive of prostate cancer; men whose MRI results were not suggestive of prostate cancer were not offered biopsy. Standard biopsy was a 10-to-12-core, transrectal ultrasonography-guided biopsy. The primary outcome was the proportion of men who received a diagnosis of clinically significant cancer. Secondary outcomes included the proportion of men who received a diagnosis of clinically insignificant cancer. Results A total of 500 men underwent randomization. In the MRI-targeted biopsy group, 71 of 252 men (28%) had MRI results that were not suggestive of prostate cancer, so they did not undergo biopsy. Clinically significant cancer was detected in 95 men (38%) in the MRI-targeted biopsy group, as compared with 64 of 248 (26%) in the standard-biopsy group (adjusted difference, 12 percentage points; 95% confidence interval [CI], 4 to 20; P=0.005). MRI, with or without targeted biopsy, was noninferior to standard biopsy, and the 95% confidence interval indicated the superiority of this strategy over standard biopsy. Fewer men in the MRI-targeted biopsy group than in the standard-biopsy group received a diagnosis of clinically insignificant cancer (adjusted difference, -13 percentage points; 95% CI, -19 to -7; P<0.001). Conclusions The use of risk assessment with MRI before biopsy and MRI-targeted biopsy was superior to standard transrectal ultrasonography-guided biopsy in men at clinical risk for prostate cancer who had not undergone biopsy previously. (Funded by the National Institute for Health Research and the European Association of Urology Research Foundation; PRECISION ClinicalTrials.gov number, NCT02380027 .)

Multiparametric Prostate Magnetic Resonance Imaging and Cognitively Targeted Transperineal Biopsy in Patients With Previous Abdominoperineal Resection and Suspicion of Prostate Cancer.

OBJECTIVE: To report our experience with a combination of prostate magnetic resonance imaging (MRI) and transperineal ultrasound biopsy for evaluating the prostate in patients with elevated prostate-specific antigen (PSA) who have previously undergone abdominoperineal resection (APR). PATIENTS AND METHODS: We reviewed the records of 11 patients with a history of APR and clinical suspicion of prostate cancer due to elevated PSA levels over a 5-year period. All patients underwent multiparametric MRI at our institution prior to biopsy. MR diagnoses were validated either by transperineal ultrasound biopsy (Likert 3-5) guided by visual registration or clinical follow-up >6 months (Likert 1-2). RESULTS: All 7 cases with highly suspicious lesions (Likert 4-5) on MRI demonstrated cancer-1 case of Gleason 3 + 3 and 6 cases of Gleason ≥3 + 4 disease. Two cases with Likert 3 MR lesions revealed benign tissue upon biopsy. Two patients with no suspicious lesions on MRI were followed-up clinically, with PSA levels remaining stable over a mean period of 17.5 months (range 7-28 months). CONCLUSION: The use of prebiopsy multiparametric prostate MRI and subsequent cognitively targeted transperineal biopsy guided by visual registration can aid in the diagnostic pathway of patients with APR and a suspicion of prostate cancer.Author 1 has received a research grant from RWTH Aachen University Hospital (Aachen, Germany). Author 6 acknowledges support from Cancer Research UK, National Institute of Health Research Cambridge Biomedical Research Centre, Cancer Research UK and the Engineering and Physical Sciences Research Council Imaging Centre in Cambridge and Manchester and the Cambridge Experimental Cancer Medicine Centre.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.urology.2016.04.03

The impact of computed high b-value images on the diagnostic accuracy of DWI for prostate cancer: A receiver operating characteristics analysis.

To evaluate the performance of computed high b value diffusion-weighted images (DWI) in prostate cancer detection. 97 consecutive patients who had undergone multiparametric MRI of the prostate followed by biopsy were reviewed. Five radiologists independently scored 138 lesions on native high b-value images (b = 1200 s/mm2), apparent diffusion coefficient (ADC) maps, and computed high b-value images (contrast equivalent to b = 2000 s/mm2) to compare their diagnostic accuracy. Receiver operating characteristic (ROC) analysis and McNemar's test were performed to assess the relative performance of computed high b value DWI, native high b-value DWI and ADC maps. No significant difference existed in the area under the curve (AUC) for ROCs comparing B1200 (b = 1200 s/mm2) to computed B2000 (c-B2000) in 5 readers. In 4 of 5 readers c-B2000 had significantly increased sensitivity and/or decreased specificity compared to B1200 (McNemar's p < 0.05), at selected thresholds of interpretation. ADC maps were less accurate than B1200 or c-B2000 for 2 of 5 readers (P < 0.05). This study detected no consistent improvement in overall diagnostic accuracy using c-B2000, compared with B1200 images. Readers detected more cancer with c-B2000 images (increased sensitivity) but also more false positive findings (decreased specificity)

Developments in MRI-targeted prostate biopsy

PURPOSE OF REVIEW: MRI-targeted prostate biopsy may be an attractive alternative to systematic biopsy for diagnosing clinically significant prostate cancer. In this narrative review, we discuss the new developments that have occurred in the advancement of MRI-targeted prostate biopsy, over the past 24 months. RECENT FINDINGS: MRI-targeted biopsy offers enhanced diagnostic accuracy, when compared with the current standard of care of systematic transrectal ultrasound-guided (TRUS) biopsy, by decreasing the overall number of biopsies needed, maintaining or improving significant prostate cancer detection, and reducing the detection of clinically insignificant prostate cancer. The necessity of combining systematic prostate biopsy with MRI-targeted biopsy is still debated. The use of MRI--ultrasound fusion systems for lesion-targeting is promising for optimizing significant cancer detection, but recent evidence suggests that additional cognitive biopsy cores are still useful in detecting additional cancers. SUMMARY: MRI-targeted biopsy in selected men with positive MRI offers a number of benefits over systematic biopsy in all men, and as such, may emerge as the new standard of care for the diagnosis of clinically significant prostate cancer