Faculty Bibliography

In patients with metallic hip implants, distortions, and other artifacts relating to the echo-planar imaging acquisition may render prostate diffusion-weighted imaging (DWI) nondiagnostic. Reduced field-of-view (rFOV) acquisition, using parallel transmission and focused excitation, is a novel DWI approach that reduces distortions and improves images quality. This article presents images from both standard and rFOV DWI acquisitions in 2 prostate cancer patients with hip implants, showing the effect of rFOV DWI for improving tumor localization. The findings have implications for the potential application of magnetic resonance imaging for guiding targeted biopsy and planning focal therapy in the growing population of patients with hip implants.

Introduction & Objectives: Standard of care for prostate cancer diagnosis in biopsy naive men is transrectal ultrasound guided prostate (TRUS) biopsy. Evidence is accumulating that MRI is useful in detecting clinically significant prostate cancer, and it is widely recommended after a negative biopsy. Controversy exists regarding its effectiveness before biopsy in all men. PRECISION aimed to evaluate whether multiparametric MRI and a targeted biopsy only (MRI+/-TB) was non-inferior to TRUS biopsy in the detection of clinically significant prostate cancer in biopsy naive men. Materials & Methods: PRECISION was a prospective, randomised, non-inferiority trial, carried out in 25 centres in 11 countries. 500 men were randomly allocated to 10-12 core TRUS-biopsy or MRI+/-TB. Men randomised to MRI+/-TB underwent MRI followed by targeted biopsy alone (without standard cores) if the PIRADSv2 score was >=3. MRI was either 1.5 or 3.0 T with at least a pelvic phased array coil, interpreted by a local radiologist, and image- registration technique was left to local expertise. Men with a PIRADSv2 score of 1-2 were not offered biopsy. Men in the 10-12 core TRUS-biopsy arm did not undergo pre-biopsy MRI. The primary outcome was the proportion of men diagnosed with clinically significant cancer (Gleason grade (GG) >= 3+4), with the non-inferiority margin for the difference in proportions set at -5%. Planned secondary outcomes included the proportion of men with clinically insignificant cancer (GG 3+3). Ethical approval was obtained for the study. Results: Baseline characteristics were similar in both MRI+/-TB and TRUS biopsy arms for mean age (64 vs 65), median PSA (6.8 vs 6.5), proportion of men with family history of prostate cancer (19% vs 16%) and proportion of men with abnormal digital rectal examination (14% vs 15%). Of 252 men randomised to MRI+/-TB, 71 (28%) avoided a biopsy. Clinically significant cancer was detected in 95 (38%) of 252 men in the MRI+/-TB arm compared to 64 (26%) of 248 men randomised to TRUS-biopsy (intention-to-treat analysis). Adjusting for centre effects, the absolute difference (MRI+/-TB versus TRUS-biopsy) in the proportion of men diagnosed with clinically significant prostate cancer was 11.8% (2-sided 95% CI 3.7 to 20.0; p = 0.005). The lower bound of the 95% CI for the difference is greater than -5% therefore MRI+/-TB was non-inferior to TRUS biopsy. Furthermore, the range of 95% CI was consistent with a claim of superiority of MRI+/-TB over TRUS-biopsy. MRI+/-TB also diagnosed fewer men with insignificant cancer than TRUS biopsy [23/252 (9%) vs 55/248 (22%), p<0.001]. Conclusions: Several benefits may be conferred by changing the standard of care from TRUS biopsy with standard cores alone, to MRI and targeted biopsy alone in men with suspicious MRI. These include fewer men biopsied, fewer cores taken, greater number of significant cancers diagnosed, and lower chance of diagnosing low risk cancer

Background: Traditional pathology reports of prostate biopsy mainly focus on presence of carcinoma but ignore other pathologic findings such as inflammation or hyperplasia. In the era of MRI-ultrasound fusion-targeted prostate biopsy (MRF-TB), where specific MRI regions of interest (ROI) are targeted for biopsy, these benign findings should be reported as they may guide decisions on when to repeat imaging or prostate biopsy. In this study, we reviewed MRF-TB prostate biopsies reported as negative for carcinoma to identify pathologic correlates to visible ROI on prostate MRI. Design: From 2012 to2016, 1595 men underwent a total of 1813 prebiopsy prostate MRI, followed by MRF-TB at our institution. We rereviewed the prostate biopsy cores for all patients with PI-RADS 4 or 5 (PI-RADS 4/5) ROI but had no cancer detected on MRF-TB. Pathologic findings were separated into two groups: significant pathologic findings (SPF, such as inflammation, hyperplasia, ASAP/HGPIN) and no significant pathologic findings (NSPF) with or without cancer in same/adjacent site on systematic biopsy (SB). Patients with repeat MRI and follow-up MRF-TB evaluation. Results: 497 men had PI-RADS 4/5 lesions out of 1595 initial biopsies. Of these 497 men, 101 (20%) had MRF-TB negative for carcinoma. Upon review, 54 had SPF and 47 had NSPF on MRF-TB. Of 54 men with SPF on initial MRF-TB, 31 had repeat MRI, 23 of 31 men downgraded in which 16 had repeat MRF-TB with 1 had cancer detect. The other 8 of 31 men had persistent PI-RADS 4/5 lesions, 3 were detected cancer on repeat MRF-TB. Of 47 men with NSPF on initial MRF-TB, 19 had PCa in the same/ adjacent site on SB and were considered as missed on MRF-TB; of the other 28, 13 underwent repeat MRI. 8 of 13 downgraded with 0 had PCa in the repeat MRF-TB and 5 of 13 men with persistent PI-RADS 4/5 lesions, 3 had PCa detect on repeat MRF-TB. Altogether, 22/47 (47%) of the cases with NSPF in the initial MRF-TB were missed cancer. Conclusions: 1/5 of the target biopsy cases on PI-RADS 4/5 ROI had negative cancer detection. Inflammation, nodular hyperplasia and HGPIN can account for some of the cases, and those were downgraded in followup MRI usually had a negative repeat biopsy. Cases with NSPF on MRF-TB for PI-RADS 4/5 lesions are likely (47%) missed PCa, high likelihood of persistent PI-RADS 4/5 ROI on repeat MRI and PCa detection on repeat biopsy. We suggest pathology findings beside cancer should be reported on MRF-TB biopsy as they can guide decisions on repeat imagine and biopsy

OBJECTIVE: To develop nomograms that predict the probability of overall PCa and clinically significant PCa (Gleason >/=7) on MRI targeted, and combined MRI-targeted and systematic, prostate biopsy. MATERIALS AND METHODS: From June 2012 to August 2014, MR-US fusion targeted prostate biopsy was performed on 464 men with suspicious regions identified on pre-biopsy 3T MRI along with systematic 12 core biopsy. Logistic regression modeling was used to evaluate predictors of overall and clinically significant PCa, and corresponding nomograms were generated for men who were not previously biopsied or had one or more prior negative biopsies. Models were created with 70% of a randomly selected training sample and bias-corrected using bootstrap resampling. The models were then validated with the remaining 30% testing sample pool. RESULTS: A total of 459 patients were included for analysis (median age 66 years, PSA 5.2 ng/ml, prostate volume 49 cc). Independent predictors of PCa on targeted and systematic prostate biopsy were PSA density, age, and MRI suspicion score. PCa probability nomograms were generated for each cohort using the predictors. Bias-corrected areas under the receiver-operating characteristic curves for overall and clinically significant PCa detection were 0.82 (0.78) and 0.91 (0.84) for men without prior biopsy and 0.76 (0.65) and 0.86 (0.87) for men with a prior negative biopsy in the training (testing) samples. CONCLUSION: PSA density, age, and MRI suspicion score predict prostate cancer on combined MRI-targeted and systematic biopsy. Our generated nomograms demonstrate high diagnostic accuracy and may further aid in the decision to perform biopsy in men with clinical suspicion of PCa.

PURPOSE: This study aimed to assess variability in imaging facilities' adherence to the minimum technical standards for prostate magnetic resonance imaging acquisition established by Prostate Imaging-Reporting and Data System (PI-RADS) version 2 (v2). METHODS: A total of 107 prostate magnetic resonance imaging examinations performed at 107 unique imaging facilities after the release of PI-RADS v2 and that were referred to a tertiary care center for secondary interpretation were included. Image sets, DICOM headers, and outside reports were reviewed to assess adherence to 21 selected PI-RADS v2 minimum technical standards. RESULTS: Hardware arrangements were 23.1%, 1.5T without endorectal coil; 7.7%, 1.5T with endorectal coil; 63.5%, 3T without endorectal coil; and 5.8%, 3T with endorectal coil. Adherence to minimum standards was lowest on T2 weighted imaging (T2WI) for frequency resolution /=1400 s/mm2) images were included in 58.0% (calculated in 25.9%). Adherence to T2WI phase resolution and DWI inter-slice gap were greater (P < .05) at 3T than at 1.5T. Adherence did not differ (P > .05) for any parameter between examinations performed with and without an endorectal coil. Adherence was greater for examinations performed at teaching facilities for T2WI slice thickness and DCE temporal resolution (P < .05). Adherence was not better for examinations performed in 2016 than in 2015 for any parameter (P > .05). CONCLUSION: Facilities' adherence to PI-RADS v2 minimum technical standards was variable, being particularly poor for T2WI frequency resolution and DCE temporal resolution. The standards warrant greater community education. Certain technical standards may be too stringent, and revisions should be considered.

OBJECTIVE: The purpose of this study was to compare the reproducibility and diagnostic performance of 2D and 3D ROIs for prostate apparent diffusion coefficient (ADC) measurements. MATERIALS AND METHODS: The study included 56 patients with prostate cancer undergoing 3-T MRI including DWI (b = 50 and 1000 s/mm2) before radical prostatectomy. Histologic findings from prostatectomy specimens were reviewed to denote each patient's dominant tumor and a benign region with visually decreased ADC. Three readers independently measured the ADCs of both areas using an ROI placed on a single slice through the lesion (2D) and an ROI encompassing all slices through the lesion (3D). Readers repeated measurements after 3 weeks. Assessment included Bland-Altman analysis (coefficient of repeatability [CR] in which lower values indicated higher reliability) and ROC analysis. RESULTS: For intrareader variability, the CRs across readers for all ROIs were 9.9% for 2D and 9.3% for 3D. For tumor ROIs the CRs were 10.6% for 2D and 9.6% for 3D. For interreader variability, the CRs across readers for all ROIs were 17.1% for 2D and 20.5% for 3D and for tumor ROIs were 17.9% for 2D and 22.2% for 3D. For combined reader data, the AUCs for benign and malignant findings were 0.77 for 2D and 0.78 for 3D (p = 0.146). For differentiating Gleason score (GS) 3 + 3 from GS > 3 + 3 tumors, the AUCs were 0.92 for 2D and 0.92 for 3D ROIs (p = 0.649). For differentiating GS /= 4 + 3 tumors, the AUCs were 0.70 for 2D and 0.67 for 3D ROIs (p = 0.004). CONCLUSION: Use of a 3D ROI did not improve intrareader or interreader reproducibility or diagnostic performance compared with use of a 2D ROI for prostate ADC measurements. Interreader reproducibility of 2D ROIs was suboptimal nonetheless.