GENITOURINARY IMAGINGM ultiparametric MRI (mpMRI) is now established as the first-line investigation for suspected prostate cancer (PCa) (1), but overall specificity for clinically significant cancer (csPCa) (Gleason score 314) is reported at a modest 37% (2,3). This results in one in two men with positive mpMRI findings undergoing biopsy, the results of which were negative for significant cancer, with associated morbidity and a health economic cost (4-6).Adjunct markers have been proposed to complement mpMRI to assist in the decision to biopsy. Several prostate-specific antigen (PSA) density (PSAD) thresholds (ranging from 0.08-0.15 ng/mL 2 ) are commonly used for men with indeterminate mpMRI findings, but no consensus exists on the optimal threshold (7,8). The apparent diffusion coefficient (ADC) is the most often investigated quantitative marker derived from mpMRI results and has shown value in differentiating significant PCa, but it can cause false-positive findings (9-11).Vascular, Extracellular, and Restricted Diffusion for Cytometry in Tumor (VERDICT) MRI is a Background: In men suspected of having prostate cancer (PCa), up to 50% of men with positive multiparametric MRI (mpMRI) findings (Prostate Imaging Reporting and Data System [PI-RADS] or Likert score of 3 or higher) have no clinically significant (Gleason score 313, benign) biopsy findings. Vascular, Extracellular, and Restricted Diffusion for Cytometry in Tumor (VERDICT) MRI analysis could improve the stratification of positive mpMRI findings.Purpose: To evaluate VERDICT MRI, mpMRI-derived apparent diffusion coefficient (ADC), and prostate-specific antigen density (PSAD) as determinants of clinically significant PCa (csPCa). Materials and Methods:Between April 2016 and December 2019, men suspected of having PCa were prospectively recruited from two centers and underwent VERDICT MRI and mpMRI at one center before undergoing targeted biopsy. Biopsied lesion ADC, lesion-derived fractional intracellular volume (FIC), and PSAD were compared between men with csPCa and those without csPCa, using nonparametric tests subdivided by Likert scores. Area under the receiver operating characteristic curve (AUC) was calculated to test diagnostic performance.Results: Among 303 biopsy-naive men, 165 study participants (mean age, 65 years 6 7 [SD]) underwent targeted biopsy; of these, 73 had csPCa. Median lesion FIC was higher in men with csPCa (FIC, 0.53) than in those without csPCa (FIC, 0.18) for Likert 3 (P = .002) and Likert 4 (0.60 vs 0.28, P , .001) lesions. Median lesion ADC was lower for Likert 4 lesions with csPCa (0.86 3 10 23 mm 2 /sec) compared with lesions without csPCa (1.12 3 10 23 mm 2 /sec, P = .03), but there was no evidence of a difference for Likert 3 lesions (0.97 3 10 23 mm 2 /sec vs 1.20 3 10 23 mm 2 /sec, P = .09). PSAD also showed no difference for Likert 3 (0.17 ng/mL 2 vs 0.12 ng/mL 2 , P = .07) or Likert 4 (0.14 ng/mL 2 vs 0.12 ng/mL 2 , P = .47) lesions. The diagnostic performance of FIC (AUC, 0.96; 95% CI: 0.93, 1.00) was higher (P = ....

Background: The accuracy of multi-parametric MRI (mpMRI) in the pre-operative staging of prostate cancer (PCa) remains controversial. Objective: The purpose of this study was to evaluate the ability of mpMRI to accurately predict PCa extra-prostatic extension (EPE) on a side-specific basis using a risk-stratified 5-point Likert scale. This study also aimed to assess the influence of mpMRI scan quality on diagnostic accuracy. Patients and Methods: We included 124 men who underwent robot-assisted RP (RARP) as part of the NeuroSAFE PROOF study at our centre. Three radiologists retrospectively reviewed mpMRI blinded to RP pathology and assigned a Likert score (1–5) for EPE on each side of the prostate. Each scan was also ascribed a Prostate Imaging Quality (PI-QUAL) score for assessing the quality of the mpMRI scan, where 1 represents the poorest and 5 represents the best diagnostic quality. Outcome measurements and statistical analyses: Diagnostic performance is presented for the binary classification of EPE, including 95% confidence intervals and the area under the receiver operating characteristic curve (AUC). Results: A total of 231 lobes from 121 men (mean age 56.9 years) were evaluated. Of these, 39 men (32.2%), or 43 lobes (18.6%), had EPE. A Likert score ≥3 had a sensitivity (SE), specificity (SP), NPV, and PPV of 90.4%, 52.3%, 96%, and 29.9%, respectively, and the AUC was 0.82 (95% CI: 0.77–0.86). The AUC was 0.76 (95% CI: 0.64–0.88), 0.78 (0.72–0.84), and 0.92 (0.88–0.96) for biparametric scans, PI-QUAL 1–3, and PI-QUAL 4–5 scans, respectively. Conclusions: MRI can be used effectively by genitourinary radiologists to rule out EPE and help inform surgical planning for men undergoing RARP. EPE prediction was more reliable when the MRI scan was (a) multi-parametric and (b) of a higher image quality according to the PI-QUAL scoring system.

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We investigate the reliability of Whole-Body Imaging ADC estimates from subjects tested and retested within- and between-scanners from different vendors with minimal differences in acquisition protocol and post-acquisition analysis. We show substantial within-subject variation in extracranial ADC estimates within- and between-scanners as measured by Limits of Agreement. We additionally show between-scan variability between scanners is dominated by between-scan variability within a scanner. Furthermore, averaging across subsequent within-scanner examinations does not substantially improve reliability of ADC estimates. We therefore conclude a post-acquisition method for reducing within-scanner variation is required to improve the reliability of ADC estimates.