Introduction: High-resolution micro-ultrasound has the capability of imaging prostate cancer based on detecting alterations in ductal anatomy, analogous to multiparametric magnetic resonance imaging (mpMRI). This technology has the potential advantages of relatively low cost, simplicity, and accessibility compared to mpMRI. This multicenter, prospective registry aims to compare the sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of mpMRI with high-resolution micro-ultrasound imaging for the detection of clinically significant prostate cancer. Methods: We included 1040 subjects at 11 sites in seven countries who had prior mpMRI and underwent ExactVu micro-ultrasound-guided biopsy. Biopsies were taken from both mpMRI targets (PI-RADS >3 and micro-ultrasound targets (PRIMUS >3). Systematic biopsies (up to 14 cores) were also performed. Various strategies were used for mpMRI target sampling, including cognitive fusion with micro-ultrasound, separate software-fusion systems, and software-fusion using the micro-ultrasound FusionVu system. Clinically significant cancer was those with Gleason grade group ≥2. Results: Overall, 39.5% were positive for clinically significant prostate cancer. Micro-ultrasound and mpMRI sensitivity was 94% vs. 90%, respectively (p=0.03), and NPV was 85% vs. 77%, respectively. Specificities of micro-ultrasound and MRI were both 22%, with similar PPV (44% vs. 43%). This represents the initial experience with the technology at most of the participating sites and, therefore, incorporates a learning curve. Number of cores, diagnostic strategy, blinding to MRI results, and experience varied between sites. Conclusions: In this initial multicenter registry, micro-ultrasound had comparable or higher sensitivity for clinically significant prostate cancer compared to mpMRI, with similar specificity. Micro-ultrasound is a low-cost, single-session option for prostate screening and targeted biopsy. Further larger-scale studies are required for validation of these findings.

Micro-Ultrasound is a new imaging modality designed as a replacement for conventional transrectal ultrasound (TRUS).Like conventional TRUS, micro-ultrasound uses an endorectal transducer to produce real-time images of the prostate and surrounding tissue, however operating at 29MHz it does so with a resolution that is 3-fold higher than conventional systems operating at 6-12MHz. This improved resolution gives micro-ultrasound the ability to image structures down to 70 microns, or the average size of the prostate acini, and so resolve tissue-structure detail which is useful in predicting the presence of cancer. First presented in 2013 through a study of radical prostatectomy correlation by Pavlovich CP, et al. [1], micro-ultrasound demonstrated promising improvements over conventional ultrasound in both sensitivity and specificity to predict prostate cancer. This work suffered from a lack of structured interpretation, as it was discovered that the appearance of cancer on microultrasound imaging was more diverse than the simple hypoechoic lesion of conventional ultrasound. Ghai S, et al. [2] provided the required protocol in 2016, along with a retrospective validation using data collected from a biopsy cohort [2]. Since that time, other

Cervical thymic cysts belong to the rare causes of neck masses and therefore are frequently not included in a preoperative differential diagnosis. Here we report our experience in managing a 7-year-old boy who presented with a three-month history of a lateral neck mass causing stridor during sleep. Clinical findings and macroscopic and histopathological features are described and reviewed with respect to the available literature. The inclusion of a cervical thymic cyst in a preoperative differential diagnosis is important for determining the extent of the neck mass and planning any surgical procedure.

RESULTS: 653 men underwent mpMRI, of which 344 underwent prostate biopsy resulting in a 47% biopsy avoidance rate, of which 83.2% were reported as PIRADS 2. Demographics included median (with interquartile range) age (67; 62-72 years), prostate specific antigen (PSA; 8.6; 6-12 ng/ml), prostate volume (36.5; 30-51 ml) and PSA density (0.24; 0.15-0.32 ng/ml3) respectively. A trend toward higher PSA, PSA density and lower prostate volume and age was observed with higher PIRADS score. A 69.8% cancer detection rate was observed, 60.5% of which were considered to have clinically significant disease. Targeted biopsies resulted in a higher proportion of positive biopsies (70%) compared to template (4.2%) and combined targeted and template (36.4%) approaches. Higher PIRADS scores were associated with clinically significant disease, no matter the biopsy approach.CONCLUSIONS: Introduction of a mpMRI-based triage system into a large public tertiary teaching hospital is feasible and leads to high rates of prostate cancer diagnosis whilst reducing unnecessary biopsies and detection of low risk prostate cancer.