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BackgroundMultiparametric MRI (mpMRI) is commonly recommended as a triage test prior to any prostate biopsy. However, there exists limited consensus on which patients with a negative prostate mpMRI could avoid prostate biopsy.PurposeTo identify which patient could safely avoid prostate biopsy when the prostate mpMRI is negative, via a radiomics-based machine learning approach.Study typeRetrospective.SubjectsThree hundred thirty patients with negative prostate 3T mpMRI between January 2016 and December 2018 were included.Field strength/sequenceA 3.0 T/T2-weighted turbo spin echo (TSE) imaging (T2 WI) and diffusion-weighted imaging (DWI).AssessmentThe integrative machine learning (iML) model was trained to predict negative prostate biopsy results, utilizing both radiomics and clinical features. The final study cohort comprised 330 consecutive patients with negative mpMRI (PI-RADS

Background: Multiparametric MRI (mpMRI) has shown a substantial impact on prostate cancer (PCa) diagnosis. However, the understanding of the spatial correlation between mpMRI performance and PCa location is still limited. Purpose: To investigate the association between mpMRI performance and tumor spatial location within the prostate using a prostate sector map, described by Prostate Imaging Reporting and Data System (PI‐RADS) v2.1. Study Type: Retrospective. Subjects: One thousand one hundred forty‐three men who underwent mpMRI before radical prostatectomy between 2010 and 2022. Field Strength/Sequence: 3.0 T. T2‐weighted turbo spin‐echo, a single‐shot spin‐echo EPI sequence for diffusion‐weighted imaging, and a gradient echo sequence for dynamic contrast‐enhanced MRI sequences. Assessment: Integrated relative cancer prevalence (rCP), detection rate (DR), and positive predictive value (PPV) maps corresponding to the prostate sector map for PCa lesions were created. The relationship between tumor location and its detection/missing by radiologists on mpMRI compared to WMHP as a reference standard was investigated. Statistical Tests: A weighted chi‐square test was performed to examine the statistical differences for rCP, DR, and PPV of the aggregated sectors within the zone, anterior/posterior, left/right prostate, and different levels of the prostate with a statistically significant level of 0.05. Results: A total of 1665 PCa lesions were identified in 1143 patients, and from those 1060 lesions were clinically significant (cs)PCa tumors (any Gleason score [GS] ≥7). Our sector‐based analysis utilizing weighted chi‐square tests suggested that the left posterior part of PZ had a high likelihood of missing csPCa lesions at a DR of 67.0%. Aggregated sector analysis indicated that the anterior or apex locations in PZ had the significantly lowest csPCa detection at 67.3% and 71.5%, respectively. Data Conclusion: Spatial characteristics of the per‐lesion‐based mpMRI performance for diagnosis of PCa were studied. Our results demonstrated that there is a spatial correlation between mpMRI performance and locations of PCa on the prostate. Evidence Level: 4 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Background: Understanding the characteristics of multiparametric MRI (mpMRI) in patients from different racial/ethnic backgrounds is important for reducing the observed gaps in clinical outcomes. Purpose: To investigate the diagnostic performance of mpMRI and quantitative MRI parameters of prostate cancer (PCa) in African American (AA) and matched White (W) men. Study Type: Retrospective. Subjects: One hundred twenty‐nine patients (43 AA, 86 W) with histologically proven PCa who underwent mpMRI before radical prostatectomy. Field Strength/Sequence: 3.0 T, T2‐weighted turbo spin echo imaging, a single‐shot spin‐echo EPI sequence diffusion‐weighted imaging, and a gradient echo sequence dynamic contrast‐enhanced MRI with an ultrafast 3D spoiled gradient‐echo sequence. Assessment: The diagnostic performance of mpMRI in AA and W men was assessed using detection rates (DRs) and positive predictive values (PPVs) in zones defined by the PI‐RADS v2.1 prostate sector map. Quantitative MRI parameters, including Ktrans and ve of clinically significant (cs) PCa (Gleason score ≥ 7) tumors were compared between AA and W sub‐cohorts after matching age, prostate‐specific antigen (PSA), and prostate volume. Statistical Tests: Weighted Pearson's chi‐square and Mann–Whitney U tests with a statistically significant level of 0.05 were used to examine differences in DR and PPV and to compare parameters between AA and matched W men, respectively. Results: A total number of 264 PCa lesions were identified in the study cohort. The PPVs in the peripheral zone (PZ) and posterior prostate of mpMRI for csPCa lesions were significantly higher in AA men than in matched W men (87.8% vs. 68.1% in PZ, and 89.3% vs. 69.6% in posterior prostate). The Ktrans of index csPCa lesions in AA men was significantly higher than in W men (0.25 ± 0.12 vs. 0.20 ± 0.08 min−1; P < 0.01). Data Conclusion: This study demonstrated race‐related differences in the diagnostic performances and quantitative MRI measures of csPCa that were not reflected in age, PSA, and prostate volume. Evidence Level: 3 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Background: Variable flip angle (VFA) imaging is widely used for the estimation of T1 relaxation in the prostate, but may have limited repeatability and reproducibility due to its sensitivity to B1+ inhomogeneity.Purpose: To assess the repeatability and reproducibility of prostate T1 estimation with and without compensating for B1+ variation.Study Type: Prospective.Population: Twenty-one volunteers were prospectively recruited and scanned twice on two 3 T MRI scanners, resulting in 84 VFA T1 exams.Field Strength/sequence: 3 T/2D saturated turbo fast low angle shot (FLASH) and 3D dual-echo FLASH.Assessment: Two B1+ mapping techniques, including reference region VFA (RR-VFA) and saturated turbo FLASH (satTFL), were used for B1+ correction, and T1 maps with and without B1+ correction were tested for intrascanner repeatability and interscanner reproducibility. Volumetric regions of interest (ROIs) were drawn on the transition zone, peripheral zone of the prostate, and the obturator internus left and right muscles in the corresponding slices.Statistical Tests: The average T1 within each ROI for each scan was compared for both intra- and interscanner variability using concordance correlation coefficient and a Bland-Altman plot.Results: Both RR-VFA-corrected T1 and satTFL-corrected T1 showed higher intra- and interscanner correlation (0.89/0.87 and 0.87/0.84, respectively) than VFA T1 (0.84 and 0.74). Bland-Altman plots showed that VFA T1 had wider 95% limits of agreement and a larger range of T1 for each tissue compared with T1 with B1+ correction.Data Conclusion: The application of B1+ correction (both RR-VFA and satTFL) to VFA T1 results in more repeatable and reproducible T1 estimation than VFA T1 . This can potentially provide improved quantification of the prostate dynamic contrast-enhanced MRI parameters. Level of Evidence 1. Technical Efficacy Stage 1. J. Magn. Reson. Imaging 2018. [ABSTRACT FROM AUTHOR]

Level of Evidence: 5 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]