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Abstract Micro-ultrasound has recently been introduced as a low-cost alternative to multi-parametric MRI for imaging prostate cancer. Early clinical studies have demonstrated promising results; however, robust validation via comparison with whole-mount pathology has yet to be achieved. Due to micro-ultrasound probe design and tissue deformation during scanning, it is difficult to accurately correlate micro-ultrasound imaging planes with ground truth whole-mount pathology slides. In this study, we developed a multi-step methodology to co-register micro-ultrasound and MRI to whole-mount pathology. The three-step process had a registration error of 3.90 ± 0.11 mm and consists of: (1) micro-ultrasound image reconstruction, (2) 3D landmark registration of micro-ultrasound to MRI, and (3) 2D capsule registration of MRI to whole-mount pathology. This process was then used in a preliminary reader study to compare the diagnostic accuracy of micro-ultrasound and MRI in 15 patients who underwent radical prostatectomy for prostate cancer. Micro-ultrasound was found to have equivalent performance to retrospective MRI review for index lesion detection (91.7% vs. 80%), while demonstrating an increased detection of tumor extent (52.5% vs. 36.7%) with similar false positive regions-of-interest (38.3% vs. 40.8%). Prospective MRI review had reduced detection of index lesions (73.3%) and tumor extent (18.9%) but improved false positive regions-of-interest (22.7%) relative to micro-ultrasound and retrospective MRI. Further evaluation is needed with a larger sample size.

Abstract. Purpose. To evaluate the preliminary validity and acceptability of a low-cost low-fidelity robotic surgery dry lab for training and assessing residents’ technical proficiency with key robotic radical prostatectomy steps. Materials and methods. Three standardized inanimate tasks were created to simulate the radical prostatectomy steps of posterior dissection, neurovascular bundle release, and urethrovesical anastomosis. Urology trainees and faculty at a single institution completed and evaluated each dry lab task. Construct validity was evaluated by comparing task completion times and Global Evaluative Assessment of Robotic Skills scores across four participant cohorts: medical students (n = 5), junior residents (n = 5), senior residents (n = 5), and attending surgeons (n = 7). Content validity, face validity, and acceptability were evaluated through a posttask survey using a 5-point Likert scale. Results. There was a significant difference in the individual and composite task completion times and Global Evaluative Assessment of Robotic Skills scores across all participant cohorts (all p < 0.01). The model was rated favorably in terms of its content validity and acceptability for use in residency training. However, model realism, compared with human tissue, was poorly rated. The dry lab production cost was less than US $25. Conclusions. This low-cost procedure-specific dry lab demonstrated evidence of content validity, construct validity, and acceptability for simulating key robotic prostatectomy technical steps and can be used to augment robot-assisted laparoscopic prostatectomy surgical training.

The purpose of our study was to compare the apparent diffusion coefficient (ADC) derived from diffusion-weighted imaging (DWI) of prostate cancer (PCa) patients with three classes of pathological Gleason scores (GS). Patients whose GS met these criteria (GS 3+3, GS 3+4, and GS 4+3) were included in this study. The DWI was performed using 𝑏 values of 0, 50, and 400 s/mm2 in 44 patients using an endorectal coil on a 1.5T MRI scanner. The apparent diffusion coefficient (ADC) values were calculated from the DWI data of patients with three different Gleason scores. In patients with a high-grade Gleason score (4+3), the ADC values were lower in the peripheral gland tissue, pathologically determined as tumor compared to low grade (3+3 and 3+4). The mean and standard deviation of the ADC values for patients with GS 3+3, GS 3+4, and GS 4+3 were 1.135±0.119, 0.976±0.103 and 0.831±0.087 mm2/sec. The ADC values were statistically significant (𝑃