The role of prostate-specific membrane antigen (PSMA)-targeted PET in comparison to mpMRI in the evaluation of intraprostatic cancer foci is not well defined. The aim of our study was to compare the diagnostic performances of PSMA PET/CT, mpMRI and PSMA PET/CT+mpMRI using 3 independent blinded readers for each modality and with histopathology as gold standard in the detection, intra-prostatic localization and local extension of primary prostate cancer.Methods: Patients with intermediate-or high-risk prostate cancer who underwent a PSMA PET/CT as part of the prospective trial (NCT03368547) and a mpMRI prior to radical prostatectomy were included. Each imaging modality was interpreted by 3 blinded independent readers unaware of the other modality result. Central majority rule was applied (2:1). Whole-mount pathology was used as the gold-standard. Imaging scans and whole-mount pathology were interpreted using the same standardized approach on a segment-and lesion-level. A "neighboring" approach was used to define imaging/pathology correlation for the detection of individual prostate cancer foci. Accuracy in determining the location, extraprostatic extension (EPE) and seminal vesicle invasion (SVI) of prostate cancer foci was assessed using receiver operating characteristic (ROC) analysis. Inter-reader agreement was calculated using inter-class coefficient (ICC) analysis. Results:The final analysis included 74 patients (14/74 -19%) intermediate risk and 60/74 -81%) high risk). Cancer detection rate (lesion-based analysis) was 85%, 83% and 87 for PSMA PET/CT, mpMRI and PSMA PET/CT+mpMRI, respectively. ΔAUC between PSMA PET/CT+mpMRI and the two imaging modalities alone for delineation of tumor localization (segment-based analysis) was statistically significant (p<0.001), but not between PSMA PET/CT and mpMRI (p=0.093). mpMRI outperformed PSMA PET/CT in detecting EPE (p=0.002) and SVI (p=0.001). On a segment-level analysis, ICC analysis showed moderate reliability among PSMA PET/CT and mpMRI readers using a 5-point Likert scale (range: 0.53 to 0.64). In the evaluation of T-staging, poor reliability was found among PSMA PET/CT readers and poor to moderate reliability was found for mpMRI readers. Conclusions: PSMA PET/CT and mpMRI have similar accuracy in the detection and intra-prostatic localization of prostate cancer foci. mpMRI performs better in identifying EPE and SVI. For the T-staging evaluation of intermediate to high-risk prostate cancer patients, mpMRI should still be considered the imaging modality of reference. Whenever available, PSMA PET/MRI or the co-registration/fusion of PSMA PET/CT and mpMRI (PSMA PET+mpMRI) should be used as it improves tumor extent delineation.

Background: To determine the diagnostic performance of qualitative and quantitative shear wave elastography (SWE) and the optimal cutoff values of the quantitative SWE parameters in differentiating malignant from benign breast masses, and to evaluate the association between the quantitative SWE parameters and histological prognostic factors. Methods: A gray scale ultrasound and SWE were prospectively performed on a total of 244 breast masses (148 benign, and 96 malignant) in 228 consecutive patients before an ultrasound-guided needle biopsy. The qualitative SWE and quantitative SWE parameters (the mean elasticity, maximum elasticity, and elasticity ratio) were measured in each mass. The diagnostic performance of SWE and the optimal cutoff values of the quantitative SWE parameters were obtained. An association analysis of the parameters and histological prognostic factors was performed. Results: The malignant masses had a more heterogeneous pattern on the qualitative SWE than benign masses (P<0.001). The quantitative SWE parameters of the malignant masses were higher than those of the benign masses (P<0.001); the mean elasticity, maximum elasticity, and elasticity ratio of the benign masses were 19.73 kPa, 23.98 kPa, and 2.78, respectively; and the mean elasticity, maximum elasticity, and elasticity ratio of the malignant masses were 88.13 kPa, 98.48 kPa, and 10.64, respectively. The optimal cutoff value of the mean elasticity was 30 kPa, of the maximum elasticity was 36 kPa, and of the elasticity ratio was 4.5. The maximum elasticity had the highest AUC. Combining the three SWE parameters to differentiate between the malignant and benign masses increased the negative predictive value (NPV), which correctly downgraded 72.73% of BI-RADS category 4A masses to BI-RADS category 3. No statistically significant association was found between the quantitative SWE parameters and the tumor grading, tumor types, axillary lymph node statuses, or molecular subtypes of the breast cancers (P>0.05). Conclusions: The qualitative and quantitative SWE provided good diagnostic performance in differentiating malignant and benign masses. The maximum elasticity of the quantitative SWE parameters had the best diagnostic performance. Adding the three combined quantitative SWE parameters to the BI-RADS category 4A masses potentially downgraded them to BI-RADS category 3 and avoided unnecessary biopsies. No statistically significant association was found between the quantitative SWE parameters and the histological prognostic factors.

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Background: Several deep learning-based techniques have been developed for prostate cancer (PCa) detection using multi-parametric MRI (mpMRI), but few of them have been rigorously evaluated relative to radiologists' performance or whole-mount histopathology (WMHP).Purpose: To compare the performance of a previously proposed deep learning algorithm, FocalNet, and expert radiologists in the detection of PCa on mpMRI with WMHP as the reference.