BACKGROUND To evaluate performance of magnetic resonance (MR)-ultrasound guided fusion biopsy in diagnosing clinically significant prostate cancer (csCaP). METHODS 1042 men underwent multi-parametric MRI (mpMRI) and fusion biopsy consecutively in a prospective trial (2009 – 2014). An expert reader graded mpMRI regions of interest (ROI) 1–5 using published protocols. The fusion biopsy device was used to obtain targeted cores from ROIs (when present) followed by a fusion-image guided 12-core systematic biopsy in all men, even if no suspicious ROI. Primary endpoint was detection of clinically significant CaP (i.e., Gleason score ≥ 7). RESULTS Among 825 men with ≥ 1 suspicious ROI of grade 3 or higher, 289 (35%) had csCaP. Powerful predictors of csCaP were ROI grade (grade 5 vs 3, OR 6.5, p<0.01) and prostate-specific antigen density (each increase of 0.05 ng/mL/cc, OR 1.4, p<0.01). Combining systematic and targeted biopsies detected more csCaP (n=289) than targeting (n=229) or systematic biopsy alone (n=199). Among patients with no suspicious ROI, 35 (16%) had csCaP on systematic biopsy. CONCLUSION In this prospective trial, MR-ultrasound fusion biopsy allowed detection of csCaP with a direct relationship with ROI grade and PSA density. The combination of targeted and systematic biopsy detected more csCaP than either modality alone; systematic biopsies revealed csCaP in 16% of men with no suspicious MRI target. Advantages of this new biopsy method are apparent, but issues of cost, training, and reliability await resolution prior to widespread adoption.

Background Conventional biopsy fails to detect the presence of some prostate cancers (PCas). Men with a prior negative biopsy but persistently elevated prostate-specific antigen (PSA) pose a diagnostic dilemma, as some harbor elusive cancer. Objective To determine whether use of magnetic resonance–ultrasound (MR-US) fusion biopsy results in improved detection of PCa compared to repeat conventional biopsy. Design, setting, and participants In a consecutive-case series, 105 subjects with prior negative biopsy and elevated PSA values underwent multiparametric magnetic resonance imaging (MRI) and fusion biopsy in an outpatient setting. Intervention Suspicious areas on multiparametric MRI were delineated and graded by a radiologist; MR–US fusion biopsy was performed by a urologist using the Artemis device; targeted and systematic biopsies were obtained regardless of MRI result. Outcome measurements and statistical analysis Detection rates of all PCa and clinically significant PCa (Gleason ≥3 + 4 or Gleason 6 with maximal cancer core length ≥4 mm) were determined. The yield of targeted biopsy was compared to systematic biopsy. The ability of an MRI grading system to predict clinically significant cancer was investigated. Stepwise multivariate logistic regression analysis was performed to determine predictors of significant cancer on biopsy. Results and limitations Fusion biopsy revealed PCa in 36 of 105 men (34%; 95% confidence interval [CI], 25–45). Seventy-two percent of men with PCa had clinically significant disease; 21 of 23 men (91%) with PCa on targeted biopsy had significant cancer compared to 15 of 28 (54%) with systematic biopsy. Degree of suspicion on MRI was the most powerful predictor of significant cancer on multivariate analysis. Twelve of 14 (86%) subjects with a highly suspicious MRI target were diagnosed with clinically significant cancer. Conclusions MR-US fusion biopsy provides improved detection of PCa in men with prior negative biopsies and elevated PSA values. Most cancers found were clinically significant.

Objectives Prostate biopsy (Bx) has for three decades been performed in a systematic, but blind fashion using 2D ultrasound (US). Herein is described the initial clinical evaluation of a 3D Bx tracking and targeting device (Artemis, Eigen, Grass Valley, CA). Our main objective was to test accuracy of the new 3D method in men undergoing first and follow-up Bx to rule out prostate cancer (CaP). Methods & Materials Patients in the study were men ages 35-87 (66.1 +/- 9.9 yrs), scheduled for Bx to rule out CaP, who entered into an IRB-approved protocol. 218 subjects underwent conventional trans-rectal US (TRUS); the tracking system was then attached to the US probe; the prostate was scanned and a 3D reconstruction was created. All Bx sites were visualized in 3D and tracked electronically. In 11 men, a pilot study was conducted to test ability of the device to return a Bx to an original site. In 47 men, multi-parametric 3 Tesla MRI – incorporating T2-weighted images, dynamic contrast enhancement, and diffusion-weighted imaging – was performed in advance of the TRUS, allowing the stored MRI images to be fused with real-time US during biopsy. Lesions on MRI were delineated by a radiologist, assigned a grade of CaP suspicion, and fused into TRUS for biopsy targeting. Results 3D Bx tracking was completed successfully in 180/218 patients, with a success rate approaching 95% among the last 50 men. Average time for Bx with the Artemis device was 15 minutes with an additional 5 minutes for MRI fusion and Bx targeting. In the tracking study, an ability to return to prior Bx sites (n=32) within 1.2 +/- 1.1 mm S.D. was demonstrated and was independent of prostate volume or location of Bx site. In the MRI fusion study, when suspicious lesions were targeted, a 33% Bx-positivity rate was found compared to a 7% positivity rate for systematic, non-targeted Bx (19/57 cores vs. 9/124 cores, p=0.03). Conclusion Use of 3D tracking and image fusion has the potential to transform MRI into a clinical tool to aid biopsy and improve current methods for diagnosis and follow-up of CaP.

Purpose We evaluated the accuracy of magnetic resonance imaging in determining the size and shape of localized prostate cancer. Materials and Methods The subjects were 114 men who underwent multi-parametric magnetic resonance imaging before radical prostatectomy with patient specific mold processing of the specimen from 2013 to 2015. T2-weighted images were used to contour the prostate capsule and cancer suspicious regions of interest. The contours were used to design and 3-dimentional print custom molds, which permitted alignment of excised prostates with magnetic resonance imaging scans. Tumors were reconstructed in 3 dimensions from digitized whole mount sections. Tumors were then matched with regions of interest and the relative geometries were compared. Results Of the 222 tumors evident on whole mount sections 118 had been identified on magnetic resonance imaging. For the 118 regions of interest mean volume was 0.8 cc and the longest 3-dimensional diameter was 17 mm. However, for matched pathological tumors, of which most were Gleason score 3 + 4 or greater, mean volume was 2.5 cc and the longest 3-dimensional diameter was 28 mm. The median tumor had a 13.5 mm maximal extent beyond the magnetic resonance imaging contour and 80% of cancer volume from matched tumors was outside region of interest boundaries. Size estimation was most accurate in the axial plane and least accurate along the base-apex axis. Conclusions Magnetic resonance imaging consistently underestimates the size and extent of prostate tumors. Prostate cancer foci had an average diameter 11 mm longer and a volume 3 times greater than T2-weighted magnetic resonance imaging segmentations. These results may have important implications for the assessment and treatment of prostate cancer.

Purpose Targeted biopsy of lesions identified on MRI may enhance detection of clinically relevant prostate cancers (CaP). We evaluate CaP detection rates in 171 consecutive men using MR-US fusion prostate biopsy. Materials and Methods Subjects underwent targeted biopsy either for active surveillance (N=106) or persistently elevated PSA but negative prior conventional biopsy (N=65). Before biopsy, each man had a multiparametric MRI at 3.0-Tesla. Lesions on MRI were outlined in 3D and assigned increasing cancer suspicion levels (image grade 1–5) by a uroradiologist. The Artemis biopsy tracking system was used to fuse the stored MRI with real-time ultrasound (US), generating a 3D prostate model on-the-fly. Working from the 3D model, transrectal biopsy of target lesions and 12 systematic biopsies were performed under local anesthesia in the clinic. Results 171 subjects (median age 65) underwent targeted biopsy. At biopsy, median PSA = 4.9 ng/ml and prostate volume = 48 cc. A targeted biopsy was three times more likely to identify cancer than a systematic biopsy (21% vs. 7%). CaP was found in 53% of men, 38% of whom had Gleason ≥7. 38% of men with Gleason ≥7 cancers were detected only on targeted biopsies. Targeted biopsy findings correlated with level of suspicion on MRI. 15 of 16 men (94%) with an image grade 5 target (highest suspicion) had CaP, including 7 with Gleason ≥7. Conclusions Prostate lesions identified on MRI can be accurately targeted using MR-US fusion biopsy by a urologist in clinic. Biopsy findings correlate with level of suspicion on MRI.