Magnetic Resonance Imaging-guided Prostate Biopsy Research Articles

Significant Prostate Cancer in Patients with PI-RADS Category 3 Lesions: A Single-Center, Retrospective Cohort Study.

The Prostate Imaging-Reporting and Data System (PI-RADS) category 3 is the most ambiguous lesion with a variable clinically significant prostate cancer (CsPCa) detection rate. Prostate-specific antigen density (PSAD) has been investigated as an adjunctive factor to improve the diagnostic efficiency of PI-RADS categories. This study aimed to investigate the utility of PSAD as an adjunctive factor in predicting CsPCA risk in patients with PI-RADS 3 lesions. The patients with an initial PI-RADS 3 category lesion (n=142) scheduled for systematic and magnetic resonance imaging-guided prostate biopsy between 2018 and 2022 were retrospectively evaluated. Demographic and clinical variables, including PSAD, were collected. The rate of CsPCa was the primary outcome. The impact of PSAD on the CsPCa detection rate was the secondary outcome. The median age was 62 years. The rate of CsPCa was 8.5% (n=12). The patients with CsPCa have significantly lower prostate volüme and higher PSAD levels than those without CsPCa (p=0.016 and p=0.012). The cut-off values of PSAD in predicting CsPCa in all PI-RADS 3 patients and patients with CsPCa and clinically insignificant prostate cancer (n=26) were ≥0.181 ng/ml2. The sensitivity and specificity values for PSAD ≥0.181 ng/ml2 were of 75% (95% CI: 42.8%-94.5%) and 81.5% (95% CI: 73.4%-88.0%) in predicting CsPCa among PI-RADS 3 category. Conclusion: PSAD values higher than 0.181 ng/ml2 can be used as an adjunctive clinical parameter in predicting CsPCa in patients with PI-RADS 3 lesions and differentiating CsPCa from clinically insignificant prostate cancer cases.

The Added Value of Systematic Sampling in In-Bore Magnetic Resonance Imaging-Guided Prostate Biopsy.

We sought to quantify the additive value of systematic biopsy (SB) using in-bore magnetic resonance (MR)-guided prostate biopsy (IBMRGpB) by retrospectively reviewing the records of 189 patients who underwent IBMRGpB for suspected prostate cancer or as part of the surveillance protocol for previously diagnosed prostate cancer. The endpoints included clinically significant and non-clinically significant cancer diagnosis. SB detected clinically significant disease in 67 (35.5%) patients. Five (2.65%) patients whose targeted biopsies indicated benign or non-clinically significant disease had clinically significant disease based on SB. SB from the lobe contralateral to the lesion detected clinically significant disease in 15 (12%) patients. The size of the prostate was larger and the percentage of lesions located in the peripheral zone of the prostate was higher in patients with SB-detected clinically significant disease. The location of the main lesion in the peripheral zone of the prostate was a predictor for clinically significant disease in the multivariate analysis (OR = 8.26, p = 0.04), a finding supported by a subgroup analysis of biopsy-naïve patients (OR = 10.52, p = 0.034). The addition of SB during IBMRGpB increased the diagnosis of clinically significant as well as non-clinically significant prostate cancer. The location of the main lesion in the peripheral zone emerged as a positive predictive factor for clinically significant disease based on SB. These findings may enhance patient-tailored management.

Kinematic and mechanical modelling of a novel 4-DOF robotic needle guide for MRI-guided prostate intervention

Traditionally ultrasound-guided biopsy has been used to diagnose prostate cancer despite of its poor soft tissue contrast and frequent false negative results. Magnetic Resonance Imaging (MRI) has the advantage of excellent soft tissue contrast for guiding and monitoring prostate biopsy. However, its working area and access in the confined MRI bore space limit the use of interventional guide devices including robotic systems. To provide robotic precision, greater access, and compact design, we designed a novel robotic mechanism that can provide four degrees of freedom (DOF) manipulation in a compact form comparable to size of manual templates. To develop the mechanism, we established a mathematical model of inverse and forward kinematics and prototyped a proof-of-concept needle guide for MRI guided prostate biopsy. The mechanism was materialized using four discs that house small passive spherical joints that can be moved by rotating the discs consisting of grooved profile. With an initial needle insertion angle range of ±15⁰, we identified mathematical and kinematic parameters for the mechanism design and fabricated the first prototype that has dimension of 40 × 110 × 180 mm3. The prototype demonstrated that the unique robotic manipulation can physically be delivered and could provide precise needle guidance including angulated needle insertion with higher structural rigidity.

The Effect of Different Types of Prostate Biopsy Techniques on Post-Biopsy Infectious Complications.

The aim of our study was to compare infectious complication rates between different prostate biopsy techniques with various number of biopsy cores. In this retrospective study, all patients from 2 hospitals who underwent prostate biopsy between 2012 and 2019 were identified. Cohorts with different types of prostate biopsies were compiled within these hospitals. Primary outcome measure was any registered infectious complication within 7 days post-biopsy. Secondary outcomes were infectious complications within 30 days, hospitalization and bacteremia. To compare the risk of infection following different prostate biopsy techniques, data was fitted into a logistic regression model adjusting for potential confounders. In total, 4,233 prostate biopsies in 3,707 patients were included. After systematic transrectal ultrasound-guided prostate biopsy (TRUSPB; 12±1.4 biopsy cores), 4.0% (2,607) of all patients had infectious complications within 7 days post-biopsy. Transperineal magnetic resonance imaging (MRI)-ultrasound fusion guided prostate biopsy (16±3.7 biopsy cores) was associated with significantly lower infection rates than systematic TRUSPB (adjusted OR: 0.29 [0.09-0.73] 95% confidence interval [CI]). Transrectal targeted MRI-ultrasound fusion guided prostate biopsy (3.1±0.8 biopsy cores) and transrectal targeted in-bore MRI guided prostate biopsy (2.8±0.8 biopsy cores) also showed fewer infectious complications than systematic TRUSPB (adjusted OR: 0.41 [0.12-1.12] 95% CI and 0.68 [0.37-1.20] 95% CI, respectively). Transperineal prostate biopsy, or transrectal prostate biopsy with reduced number of biopsy cores, could lower the risk of infectious complications.

Active surveillance inclusion criteria under scrutiny in magnetic resonance imaging-guided prostate biopsy: a multicenter cohort study

BackgroundAlthough multiparametric magnetic resonance imaging (mpMRI) is recommended for primary risk stratification and follow-up in Active Surveillance (AS), it is not part of common AS inclusion criteria. The objective was to compare AS eligibility by systematic biopsy (SB) and combined MRI-targeted (MRI-TB) and SB within real-world data using current AS guidelines.MethodsA retrospective multicenter study was conducted by a German prostate cancer (PCa) working group representing six tertiary referral centers and one outpatient practice. Men with PCa and at least one MRI-visible lesion according to Prostate Imaging Reporting and Data System (PI-RADS) v2 were included. Twenty different AS inclusion criteria of international guidelines were applied to calculate AS eligibility using either a SB or a combined MRI-TB and SB. Reasons for AS exclusion were assessed.ResultsOf 1941 patients with PCa, per guideline, 583–1112 patients with PCa in both MRI-TB and SB were available for analysis. Using SB, a median of 22.1% (range 6.4–72.4%) were eligible for AS. Using the combined approach, a median of 15% (range 1.7–68.3%) were eligible for AS. Addition of MRI-TB led to a 32.1% reduction of suitable patients. Besides Gleason Score upgrading, the maximum number of positive cores were the most frequent exclusion criterion. Variability in MRI and biopsy protocols potentially limit the results.ConclusionsOnly a moderate number of patients with PCa can be monitored by AS to defer active treatment using current guidelines for inclusion in a real-world setting. By an additional MRI-TB, this number is markedly reduced. These results underline the need for a contemporary adjustment of AS inclusion criteria.

Preliminary Evaluation of Hydraulic Needle Delivery System for Magnetic Resonance Imaging-Guided Prostate Biopsy Procedures

Abstract In clinical routine, the prostate biopsy procedure is performed with the guidance of transrectal ultrasound (TRUS) imaging to diagnose prostate cancer. However, the TRUS-guided prostate biopsy brings reliability concerns due to the lack of contrast difference between prostate tissue and lesions. In this study, a novel hydraulic needle delivery system that is designed for performing magnetic resonance imaging (MRI)-guided prostate biopsy procedure with transperineal approach is introduced. The feasibility of the overall system was evaluated through in vitro phantom experiments under an MRI guidance. The in vitro experiments performed using a certified prostate phantom (incorporating MRI visible lesions). MRI experiments showed that overall hydraulic biopsy needle delivery system has excellent MRI compatibility (signal to noise ratio (SNR) loss < 3%), provides acceptable targeting accuracy (average 2.05±0.46 mm) and procedure time (average 40 min).

A prostate cancer risk calculator: Use of clinical and magnetic resonance imaging data to predict biopsy outcome in North American men.

A functional tool to optimize patient selection for magnetic resonance imaging (MRI)-guided prostate biopsy (MRGB) is an unmet clinical need. We sought to develop a prostate cancer risk calculator (PCRC-MRI) that combines MRI and clinical characteristics to aid decision-making for MRGB in North American men. Two prospective registries containing 2354 consecutive men undergoing MRGB (September 2009 to April 2019) were analyzed. Patients were randomized into five groups, with one group randomly assigned to be the validation cohort against the other four groups as the discovery cohort. The primary outcome was detection of clinically significant prostate cancer (csPCa) defined as Gleason grade group ≥2. Variables included age, ethnicity, digital rectal exam (DRE), prior biopsy, prostate-specific antigen (PSA), prostate volume, PSA density, and MRI score. Odds ratios (OR) were calculated from multivariate logistic regression comparing two models: one with clinical variables only (clinical) against a second combining clinical variables with MRI data (clinical+MRI). csPCa was present in 942 (40%) of the 2354 men available for study. The positive and negative predictive values for csPCa in the clinical+MRI model were 57% and 89%, respectively. The area under the curve of the clinical+MRI model was superior to the clinical model in discovery (0.843 vs. 0.707, p<0.0001) and validation (0.888 vs. 0.757, p<0.0001) cohorts. Use of PCRC-MRI would have avoided approximately 16 unnecessary biopsies in every 100 men. Of all variables examined, Asian ethnicity was the most protective factor (OR 0.46, 0.29-0.75) while MRI score 5 indicated greatest risk (OR15.8, 10.5-23.9). A risk calculator (PCRC-MRI), based on a large North American cohort, is shown to improve patient selection for MRGB, especially in preventing unnecessary biopsies. This tool is available at https://www.uclahealth.org/urology/prostate-cancer-riskcalculator and may help rationalize biopsy decision-making.

1036 - Predictors of clinically significant disease on systematic cores only in magnetic resonance imaging-guided prostate biopsy

1036 - Predictors of clinically significant disease on systematic cores only in magnetic resonance imaging-guided prostate biopsy

Accuracy of Sampling PI-RADS 4–5 Index Lesions Alone by MRI-guided In-bore Biopsy in Biopsy–naive Patients Undergoing Radical Prostatectomy

BackgroundTargeting multiparametric magnetic resonance imaging (MP-MRI)-suspicious regions alone in biopsy-naive patients is not common practice, since it may miss clinically significant prostate cancer (PCa). ObjectiveTo investigate the accuracy of in-bore MRI-guided biopsy of Prostate Imaging Reporting and Data System (PI-RADS) 4 and 5 index lesions alone in biopsy-naive patients undergoing radical prostatectomy (RP). Design, setting, and participantsA total of 170 patients underwent MRI-guided in-bore biopsy for PI-RADS 4 and 5 index lesions alone between 2013 and 2018, of whom 136 patients were diagnosed with PCa. Fifty-two patients without prior biopsy who underwent RP were included in this study. MP-MRI findings, biopsy results, and whole-mount step-section specimen evaluation were retrospectively analyzed. Outcome measurements and statistical analysisContinuous variables were reported as mean (standard deviation) or median (range). Differences in parametric variables were calculated by Student t test. Results and limitationsOverall International Society of Urological Pathology grade group (GG) up- and downgrading rates were 23.0% and 7.6% per patient and 24.5% and 6.5% per focus, respectively. Ten of 12 biopsy-detected GG 1 foci were upgraded in the final pathology. In 30 patients, a total of 43 different tumor foci were identified outside the sampled index lesion. Average biopsied and nonbiopsied tumor volumes were found to be 2.02 and 0.45 cm³, respectively (p < 0.001). The index lesion was the largest focus of tumor in all patients’ final histopathological examination; upgrading was identified in only one nonbiopsied focus in a single patient. Limitations include retrospective design and nonstandard indications of in-bore MRI biopsy. ConclusionsIn-bore MRI-guided biopsy of PI-RADS 4–5 index lesions alone in biopsy-naive patients is a safe and accurate diagnostic modality allowing appropriate patient selection for individualized treatment. Patient summaryIn-bore magnetic resonance imaging–guided prostate biopsy of suspicious lesions alone allows accurate risk stratification of patients and reduces the detection of insignificant prostate cancer.

Adoption of Prebiopsy Magnetic Resonance Imaging for Men Undergoing Prostate Biopsy in the United States

To assess adoption of prebiopsy prostate magnetic resonance imaging (MRI) in the United States and to evaluate factors associated with magnetic resonance imaging-guided prostate biopsy (MRI-Bx) use. Prior reports have shown improved cancer detection with MRI-Bx vs transrectal ultrasound-guided methods (transrectal ultrasound-guided biopsy [TRUS-Bx]). Population-based trends of their use and outcomes have not been previously characterized. Using private insurance claims (2009-2015), we identified men who underwent prostate biopsy. Exposures were biopsy year and geographic region defined by metropolitan statistical area. Outcomes included biopsy type (MRI-Bx, TRUS-Bx, or transperineal biopsy) based on procedure codes and cancer detection based on a new diagnosis for prostate cancer (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] 185). Hierarchical mixed-effects multivariable regression estimated odds of undergoing MRI-Bx. We identified 241,681 men (mean age 57.5 ± 5.4 years) who underwent biopsy. The use of MRI-Bx rose rapidly (0.2% in 2009 to 6.5% in 2015, P <.001). Overall, 3429 men underwent MRI before biopsy, more commonly in metropolitan statistical areas (odds ratio 1.90, 95% confidence interval 1.66-2.19). In 2015, nearly 18% of men with prior negative biopsy underwent a prebiopsy MRI. Patients with prior negative biopsies were over 4 times more likely to use MRI guidance (vs no prior biopsies, odds ratio 4.63, 95% confidence interval 4.27-5.02) and had a greater chance of cancer detection with MRI-Bx (25.2%) vs TRUS-Bx (19.7%, P = .010). Among men undergoing prostate biopsy, prebiopsy prostate MRI utilization was concentrated within urban areas and among patients with prior negative biopsies, where its use was associated with superior cancer detection compared with traditional TRUS-Bx.

Cognitive-Targeted versus Magnetic Resonance Imaging-Guided Prostate Biopsy in Prostate Cancer Detection

Introduction: Purpose of this study is to evaluate the detection rates of prostate cancer (PCa) for cognitive-targeted biopsy (CTB) in comparison with magnetic resonance imaging (MRI)-guided biopsy (MRGB) related to prostate imaging reporting and data system (PI-RADS) score, lesion location and lesion volume. Furthermore, the addition of systematic transrectal ultrasound-guided biopsy (TRUS-GB) to CTB is evaluated. Materials and Methods: We included all patients with cancer-suspicious lesions on 3-Tesla multiparametric MRI who underwent either CTB and additional TRUS-GB or only MRGB (in-bore) in Haga Teaching Hospital between January 2013 and January 2015. Results: In total 219 patients were included: 64 CTB + TRUS-GB and 155 MRGB. In 32 (50%) men with CTB was positive for PCa. PI-RADS 3-, 4- and 5-lesions were in 17, 69 and 95% positive, respectively. In 100 men (65%) with MRGB was positive for PCa. Detection rates for PI-RADS 3-, 4- and 5-lesions were 10, 77 and 89%, respectively. CTB missed 4 (11%) low-grade tumors detected by TRUS-GB. In lesions between 0-1.5 ml PCa were significantly more often detected with MRGB than with CTB (69 vs. 39%). Conclusion: CTB has a high detection rate of PCa in men with cancer-suspicious lesions on MRI. Correction for lesion volume shows that in lesions < 1.5 ml MRGB is more accurate than CTB. The addition of TRUS-GB to CTB can safely be avoided without missing any high grade PCa.

Pathologic correlation of transperineal in-bore 3-Tesla magnetic resonance imaging-guided prostate biopsy samples with radical prostatectomy specimen.

To determine the accuracy of in-bore transperineal 3-Tesla (T) magnetic resonance (MR) imaging-guided prostate biopsies for predicting final Gleason grades in patients who subsequently underwent radical prostatectomy (RP). A retrospective review of men who underwent transperineal MR imaging-guided prostate biopsy (tpMRGB) with subsequent radical prostatectomy within 1 year was conducted from 2010 to 2015. All patients underwent a baseline 3-T multiparametric MRI (mpMRI) with endorectal coil and were selected for biopsy based on MR findings of a suspicious prostate lesion and high degree of clinical suspicion for cancer. Spearman correlation was performed to assess concordance between tpMRGB and final RP pathology among patients with and without previous transrectal ultrasound (TRUS)-guided biopsies. A total of 24 men met all eligibility requirements, with a median age of 65 years (interquartile range [IQR] 11.7). The median time from biopsy to RP was 85 days (IQR 50.5). Final pathology revealed Gleason 3+4=7 in 12 patients, 4+3=7 in 10 patients, and 4+4=8 in 2 patients. A strong correlation (ρ: +0.75, p<0.001) between tpMRGB and RP results was observed, with Gleason scores concordant in 17 cases (71%). 16 of the 24 patients underwent prior TRUS biopsies. Subsequent tpMRGB revealed Gleason upgrading in 88% of cases, which was concordant with RP Gleason scores in 69% of cases (ρ: +0.75, p<0.001). Final Gleason scores diagnosed by tpMRGB at 3-T correlate strongly with final RP surgical pathology. This may facilitate prostate cancer diagnosis, particularly in patients with negative or low-grade TRUS biopsy results in whom clinically significant cancer is suspected or detected on mpMRI.

Prostate cancer detection rates of magnetic resonance imaging-guided prostate biopsy related to Prostate Imaging Reporting and Data System score.

Recent studies have shown that multiparametric magnetic resonance imaging and magnetic resonance imaging-guided prostate biopsy in patients with suspected prostate cancer increase detection rate and clinical significance of diagnosed tumors. Purpose of this study is to evaluate the detection rates of prostate cancer for magnetic resonance imaging-guided prostate biopsy related to Prostate Imaging Reporting and Data System score. We included all patients with cancer-suspicious lesions on 3-Tesla multiparametric magnetic resonance imaging-prostate who underwent magnetic resonance imaging-guided prostate biopsy in Haga Teaching Hospital between January 2013 and January 2015. In total, 155 patients were included. In 100 of 155 (65%) men, MRI-guided prostate biopsy was positive for prostate cancer. No biopsy of PI-RADS 2-lesions was positive. PI-RADS 3- and 4-lesions were, respectively, in 10 and 77% prostate cancer positive. Biopsies of PI-RADS 5-lesions were in 89% of the cases positive. The majority of detected cancers (63%) were Gleason score ≥7, and this number increases to 75% in positive PI-RADS 5-lesions. Magnetic resonance imaging-guided prostate biopsy has a high detection rate of prostate cancer in men with cancer-suspicious lesions on multiparametric magnetic resonance imaging-prostate, and this rate (65%) increases with the Prostate Imaging Reporting and Data System score (81% in PI-RADS 4- and 5-lesions).

Impact of magnetic resonance imaging-guided prostate biopsy in the supine position on the detection of significant prostate cancer in an inhomogeneous patient cohort

Objective: The aim of this study was to determine the tumour detection rate of magnetic resonance-guided biopsy (MRGB) in the supine position for significant prostate cancer in an inhomogeneous patient cohort. Materials and methods: Thirty-two consecutive patients with a total prostate-specific antigen > 4 ng/ml and/or a tumour-suspicious palpable lesion upon digital rectal examination and a cancer-suspicious region in multiparametric magnetic resonance imaging (MRI) underwent MRGB in a standard 1.5 T magnet. Diagnostic MRI was performed in 20 patients at the authors’ institute and 12 men at another location. Eight patients were investigated at 3 T and 24 at 1.5 T. Twenty men had prior negative biopsies and 12 were biopsy naïve. All biopsies were performed in the supine position using a table-mounted device and an 18 G biopsy gun. Results: The overall tumour detection rate was 53% (17/32). Two cores (median; range 1–4) were extracted. Clinically significant cancers were found in 94% (16/17). None of the patients showed any postbiopsy complications. The prostate volumes of patients with cancer were significantly lower (39.3 ml) than those of men without cancer (49.7 ml). No significant differences were found between the numbers of tumour-positive and tumour-negative collected cores. In a median follow-up of 14 months, no cancer was detected in the negative biopsy group. Conclusion: MRGB in the supine position can be a valuable tool to detect significant prostate cancer, even in a patient cohort with different prebiopsy pathways. The biopsy method could be a reasonable alternative to MRGB in the prone position.

Magnetic resonance imaging-guided prostate biopsy: present and future.

Systemic transrectal ultrasound-guided biopsy (TRUSBx) is the standard procedure for diagnosing prostate cancer (PCa), but reveals a limited accuracy for the detection of cancer. Currently, multiparametric MR imaging (mp-MRI) is increasingly regarded as a promising method to detect PCa with an excellent positive predictive value. The use of mp-MRI during a MRI-guided biopsy (MRGB) procedure improves the quality of a targeted biopsy. The aim of this article is to provide an overview about the MRGB technique for PCa detection, to review the accuracy and clinical indications of MRGB and discuss its current issues and further directions. A MRGB seems accurate and efficient for the detection of clinically significant PCa in men with previous negative TRUSBx. Moreover, it may decrease the detection of clinically insignificant cancers with fewer biopsy cores.

Transperineal in-bore 3-T MR imaging-guided prostate biopsy: a prospective clinical observational study.

To determine the detection rate, clinical relevance, Gleason grade, and location of prostate cancer ( PCa prostate cancer ) diagnosed with and the safety of an in-bore transperineal 3-T magnetic resonance (MR) imaging-guided prostate biopsy in a clinically heterogeneous patient population. This prospective retrospectively analyzed study was HIPAA compliant and institutional review board approved, and informed consent was obtained. Eighty-seven men (mean age, 66.2 years ± 6.9) underwent multiparametric endorectal prostate MR imaging at 3 T and transperineal MR imaging-guided biopsy. Three subgroups of patients with at least one lesion suspicious for cancer were included: men with no prior PCa prostate cancer diagnosis, men with PCa prostate cancer who were undergoing active surveillance, and men with treated PCa prostate cancer and suspected recurrence. Exclusion criteria were prior prostatectomy and/or contraindication to 3-T MR imaging. The transperineal MR imaging-guided biopsy was performed in a 70-cm wide-bore 3-T device. Overall patient biopsy outcomes, cancer detection rates, Gleason grade, and location for each subgroup were evaluated and statistically compared by using χ(2) and one-way analysis of variance followed by Tukey honestly significant difference post hoc comparisons. Ninety biopsy procedures were performed with no serious adverse events, with a mean of 3.7 targets sampled per gland. Cancer was detected in 51 (56.7%) men: 48.1% (25 of 52) with no prior PCa prostate cancer , 61.5% (eight of 13) under active surveillance, and 72.0% (18 of 25) in whom recurrence was suspected. Gleason pattern 4 or higher was diagnosed in 78.1% (25 of 32) in the no prior PCa prostate cancer and active surveillance groups. Gleason scores were not assigned in the suspected recurrence group. MR targets located in the anterior prostate had the highest cancer yield (40 of 64, 62.5%) compared with those for the other parts of the prostate (P < .001). In-bore 3-T transperineal MR imaging-guided biopsy, with a mean of 3.7 targets per gland, allowed detection of many clinically relevant cancers, many of which were located anteriorly.

Magnetic Resonance Imaging-Guided Prostate Biopsy: Institutional Analysis and Systematic Review

To evaluate the detection rate of prostate cancer (PCa) after magnetic resonance-guided biopsy (MRGB); to monitor the patient cohort with negative MRGB results and to compare our own results with other reports in the current literature. A group of 41 patients was included in this IRB-approved study and subjected to combined MRI and MRGB. MRGB was performed in a closed 1.5 T MR unit and the needle was inserted rectally. The follow-up period ranged between 12 and 62 months (mean 3.1 years). To compare the results with the literature, a systematic literature search was performed. Eighteen publications were evaluated. The cancer-suspicious regions were punctured successfully in all cases. PCa was detected in eleven patients (26.9 %) who were all clinically significant. MRGB showed a benign histology in the remaining 30 patients. In the follow-up (mean 3.1 years) of patients with benign histology, no new PCa was diagnosed. The missed cancer rate during follow-up was 0.0 % in our study. MRGB is effective for the detection of clinically significant cancer, and this is in accordance with the recent literature. In the follow-up of patients with benign histology, no new PCa was discovered. Although the probability of developing PCa after negative MRGB is very low, active surveillance is reasonable.

Magnetic Resonance Imaging-Guided Prostate Biopsy: How We Do It

Introduction: Prostate biopsy is typically performed under transrectal ultrasound (TRUS) guidance. However, even after multiple negative TRUS biopsies, the considerable risk of prostate cancer (PCa) remains due to undersampling.1,2 Magnetic resonance imaging (MRI) is increasingly used in clinical practice to guide prostate biopsies.3,4 In this video, we describe how we perform in-bore MRI-guided prostate biopsy and present an overview of this biopsy technique. The runtime of this video is 5:08 min. Materials and Methods: The biopsy procedure is illustrated by a clinical case of a 61-year-old male with a high clinical suspicion of PCa referred to our institution after six negative TRUS biopsy sessions. On preceding multiparametric MRI, a cancer suspicious region was identified at the left ventral transition zone. Targeted biopsy of this lesion was performed in a transrectal approach on a 3 T MR system using an MR-compatible biopsy device. In total, two biopsy cores were obtained from the suspicious region. Results and Conclusions: The illustrated case was performed in 26 minutes. On histopathology, a Gleason score 4+3 = 7 adenocarcinoma was present in, respectively, 8% and 50% of biopsy specimen volumes. In our institutional experience, an MRI-guided prostate biopsy in patients with previous negative TRUS biopsies achieved PCa detection rates in the order of 41%–59% using a median of three to four cores.5,6 Of detected cancers, 87%–93% was clinically significant. Median procedure time was 30–44 minutes. Urosepsis occurred in 0.4% of patients. Minor complications were observed in 1%–1.5% of patients. Overall, MRI-guided biopsy achieves high diagnostic performance, detecting more and predominantly clinically significant cancers using less cores than TRUS biopsy.7 Complication rates between both biopsy techniques are comparable.7 However, longer procedure times and limited general availability are limitations of the MRI-guided biopsy method. In conclusion, we feel that in-bore MRI-guided biopsy is an accurate and safe diagnostic tool to detect clinically significant PCa in patients with previous negative TRUS biopsies. C.O., J.B., D.Y.: Nothing to disclose; J.F.: Consultancy for Invivo, Schwerin, Germany. Runtime of video: 5 mins 8 secs

Imaging-guided Prostate Biopsy: Conventional and Emerging Techniques

Transrectal ultrasonography (US)-guided biopsy is the standard approach for histopathologic diagnosis of prostate cancer. However, this technique has multiple limitations owing to the operator's inability in most cases to directly visualize and target prostate lesions. Magnetic resonance (MR) imaging of the prostate overcomes many of these limitations by directly depicting areas of abnormality and allowing targeted biopsies. Accuracy in the detection of prostate cancer is improved by the combined use of standard T2-weighted MR imaging and advanced MR imaging techniques such as diffusion-weighted imaging, dynamic contrast-enhanced imaging, and MR spectroscopy. Suspicious-appearing regions of the prostate seen on MR images can be targeted at real-time transrectal US-guided biopsy to improve the diagnostic yield. MR imaging also can be performed for real-time guidance of transrectal prostate biopsy. Studies among patients who underwent at least one transrectal US-guided biopsy with a negative result before undergoing an MR imaging-guided biopsy showed improved detection rates with MR imaging-guided biopsy in comparison with the detection rates achieved with a repeat transrectal US-guided biopsy; however, MR imaging-guided biopsy is a more time-consuming procedure. A technique known as fused MR imaging- and transrectal US-guided biopsy, which relies on the coregistration of previously acquired MR images with real-time transrectal US images acquired during the procedure, shows promise but is limited by deformation of the prostate; this limitation is the subject of ongoing investigation. Another technique that is currently under investigation, MR imaging-guided prostate biopsy with robotic assistance, may one day help improve the accuracy of biopsy needle placement.

Feasibility of a Pneumatically Actuated MR-compatible Robot for Transrectal Prostate Biopsy Guidance

To assess the feasibility of using a remote-controlled, pneumatically actuated magnetic resonance (MR)-compatible robotic device to aid transrectal biopsy of the prostate performed with real-time 3-T MR imaging guidance. This prospective study was approved by the ethics review board, and written informed consent was obtained from all patients. Twelve consecutive men who were clinically suspected of having prostate cancer and had a history of at least one transrectal ultrasonography (US)-guided prostate biopsy with negative results underwent diagnostic multiparametric MR imaging of the prostate. Two radiologists in consensus identified cancer-suspicious regions (CSRs) in 10 patients. These regions were subsequently targeted with the robot for MR imaging-guided prostate biopsy. To direct the needle guide toward the CSRs, the MR-compatible robotic device was remote controlled at the MR console by means of a controller and a graphical user interface for real-time MR imaging guidance of the needle guide. The ability to reach the CSRs with the robot for biopsy was analyzed. A total of 17 CSRs were detected in 10 patients at the diagnostic MR examinations. These regions were targeted for MR imaging-guided robot-assisted prostate biopsy. Thirteen (76%) of the 17 CSRs could be reached with the robot for biopsy. Biopsy of the remaining four CSRs was performed without use of the robot. It is feasible to perform transrectal prostate biopsy with real-time 3-T MR imaging guidance with the aid of a remote-controlled, pneumatically actuated MR-compatible robotic device.