Novel contrast-enhanced ultrasound imaging in prostate cancer

The purposes of this paper were to present the current status of contrast-enhanced transrectal ultrasound imaging and to discuss the latest achievements and techniques now under preclinical testing. Although grayscale transrectal ultrasound is the standard method for prostate imaging, it lacks accuracy in the detection and localization of prostate cancer. With the introduction of contrast-enhanced ultrasound (CEUS), perfusion imaging of the microvascularization became available. By this, cancer-induced neovascularisation can be visualized with the potential to improve ultrasound imaging for prostate cancer detection and localization significantly. For example, several studies have shown that CEUS-guided biopsies have the same or higher PCa detection rate compared with systematic biopsies with less biopsies needed. This paper describes the current status of CEUS and discusses novel quantification techniques that can improve the accuracy even further. Furthermore, quantification might decrease the user-dependency, opening the door to use in the routine clinical environment. A new generation of targeted microbubbles is now under pre-clinical testing and showed avidly binding to VEGFR-2, a receptor up-regulated in prostate cancer due to angiogenesis. The first publications regarding a targeted microbubble ready for human use will be discussed. Ultrasound-assisted drug delivery gives rise to a whole new set of therapeutic options, also for prostate cancer. A major breakthrough in the future can be expected from the clinical use of targeted microbubbles for drug delivery for prostate cancer diagnosis as well as treatmen

Accurate validation of ultrasound imaging of prostate cancer:a review of challenges in registration of imaging and histopathology

\u3cp\u3eAs the development of modalities for prostate cancer (PCa) imaging advances, the challenge of accurate registration between images and histopathologic ground truth becomes more pressing. Localization of PCa, rather than detection, requires a pixel-to-pixel validation of imaging based on histopathology after radical prostatectomy. Such a registration procedure is challenging for ultrasound modalities; not only the deformations of the prostate after resection have to be taken into account, but also the deformation due to the employed transrectal probe and the mismatch in orientation between imaging planes and pathology slices. In this work, we review the latest techniques to facilitate accurate validation of PCa localization in ultrasound imaging studies and extrapolate a general strategy for implementation of a registration procedure.\u3c/p\u3

The added value of systematic biopsy in men with suspicion of prostate cancer undergoing multiparametric MRI-targeted biopsy

\u3cp\u3ePURPOSE: Incorporation of multiparametric magnetic resonance imaging (mpMRI) and targeted biopsy (TBx) in the diagnostic pathway for prostate cancer (CaP) is rapidly becoming common practice. In men with a prebiopsy positive mpMRI a TBx only approach, thereby omitting transrectal ultrasound-guided systematic biopsy (SBx), has been postulated. In this study we evaluated the additional clinical relevance of SBx in men with a positive prebiopsy mpMRI (Prostate Imaging Reporting and Data System [PI-RADS] ≥ 3) undergoing TBx for CaP detection, Gleason grading and CaP localization.\u3c/p\u3e\u3cp\u3eMATERIAL AND METHODS: Prospective data of 255 consecutive men with a prebiopsy positive mpMRI (PI-RADS ≥ 3) undergoing 12-core SBx and subsequent MRI-transrectal ultrasound fusion TBx in 2 institutions between 2015 and 2018 was obtained. The detection rate for significant CaP (Gleason score [GS] ≥ 3 + 4) for TBx and SBx were compared. The rate of potentially missed significant CaP by a TBx only approach was determined and GS concordance and CaP localization by TBx and SBx was evaluated.\u3c/p\u3e\u3cp\u3eRESULTS: TBx yielded significant CaP in 113 men (44%) while SBx yielded significant CaP in 110 men (43%) (P = 0.856). Insignificant CaP was found in 21 men (8%) by TBx, while SBx detected 34 men (13%) with insignificant CaP (P = 0.035). A TBx only approach, omitting SBx, would have missed significant CaP in 13 of the 126 men (10%) with significant CaP on biopsy. Ten of the 118 men (8%), both positive on TBx and SBx, were upgraded in GS by SBx while 11 men (9%) had higher maximum tumor core involvement on SBx. Nineteen of the 97 men (20%) with significant CaP in both TBx and SBx were diagnosed with unilateral significant CaP on mpMRI and TBx while SBx demonstrated bilateral significant CaP.\u3c/p\u3e\u3cp\u3eCONCLUSIONS: In men with a prebiopsy positive mpMRI, TBx detects high-GS CaP while reducing insignificant CaP detection as compared to SBx. SBx and TBx as stand-alone missed significant CaP in 13% and 10% of the men with significant CaP on biopsy, respectively. A combination of SBx and TBx remains necessary for the most accurate assessment of detection, grading, tumor core involvement, and localization of CaP.\u3c/p\u3

555 - Contrast enhanced ultrasound for the localization of prostate cancer – correlation with radical prostatectomy specimens

Introduction & Objectives: Trans Rectal UltraSound (TRUS) is an affordable, portable and safe imaging platform well known to the urologist for prostate imaging. However, prostate cancer (PCa) cannot be visualized with Greyscale TRUS. In Contrast-Enhanced UltraSound (CEUS), an intravenous Ultrasound Contrast Agent (UCA) consisting of gas filled microbubbles is used to visualize PCa-associated vascular anomalies. Contrast-ultrasound dispersion imaging (CUDI) analyses the UCA dispersion patterns as the UCA spreads through the prostate, with the intention to objectify and simplify the interpretation of CEUS. The aim was to determine the value of 2D CEUS imaging and the additional value of CUDI derived parametric maps for the localization of significant PCa

PT159 - Automatic segmentation of the prostate in transrectal ultrasound images using deep learning for application in MRI-TRUS fusion

Introduction & Objectives: In recent years, prostate biopsy increasingly involves targeting magnetic resonance imaging (MRI)-suspicious lesions after fusion with real-time transrectal ultrasound (TRUS). Such fusion currently requires (semi)manual prostate delineation, burdening clinicians with this lengthy procedure. A reliable automatic prostate segmentation on TRUS is still an unsolved challenge; therefore, here we propose a real-time prostate segmentation algorithm through deep-learning that readily translates between different scanners and user settings

Concordance of Gleason grading with three-dimensional ultrasound systematic biopsy and biopsy core pre-embedding

\u3cp\u3ePurpose: To determine the value of a three-dimensional (3D) greyscale transrectal ultrasound (TRUS)-guided prostate biopsy system and biopsy core pre-embedding method on concordance between Gleason scores of needle biopsies and radical prostatectomy (RP) specimens. Methods: Retrospective analysis of prostate biopsies and subsequent RP for PCa in the Jeroen Bosch Hospital, the Netherlands, from 2007 to 2016. Two cohorts were analysed: conventional 2D TRUS-guided biopsies and RP (2007–2013, n = 266) versus 3D TRUS-guided biopsies with pre-embedding (2013–2016, n = 129). The impact of 3D TRUS-guidance with pre-embedding on Gleason score (GS) concordance between biopsy and RP was evaluated using the κ-coefficient. Predictors of biopsy GS 6 upgrading were assessed using logistic regression models. Results: Gleason concordance was comparable between the two cohorts with a κ = 0.44 for the 3D cohort, compared to κ = 0.42 for the 2D cohort. 3D TRUS-guidance with pre-embedding, did not significantly affect the risk of biopsy GS 6 upgrading in univariate and multivariate analysis. Conclusions: 3D TRUS-guidance with biopsy core pre-embedding did not improve Gleason concordance. Improved detection techniques are needed for recognition of low-grade disease upgrading.\u3c/p\u3