A Description and Safety Overview of Irreversible Electroporation for Prostate Tissue Ablation in Intermediate-Risk Prostate Cancer Patients: Preliminary Results from the PRESERVE Trial.

The PRESERVE study (NCT04972097) aims to evaluate the safety and effectiveness of the NanoKnife System to ablate prostate tissue in patients with intermediate-risk prostate cancer (PCa). The NanoKnife uses irreversible electroporation (IRE) to deliver high-voltage electrical pulses to change the permeability of cell membranes, leading to cell death. A total of 121 subjects with organ-confined PCa ≤ T2c, prostate-specific antigens (PSAs) ≤ 15 ng/mL, and a Gleason score of 3 + 4 or 4 + 3 underwent focal ablation of the index lesion. The primary endpoints included negative in-field biopsy and adverse event incidence, type, and severity through 12 months. At the time of analysis, the trial had completed accrual with preliminary follow-up available. Demographics, disease characteristics, procedural details, PSA responses, and adverse events (AEs) are presented. The median (IQR) age at screening was 67.0 (61.0-72.0) years and Gleason distribution 3 + 4 (80.2%) and 4 + 3 (19.8%). At 6 months, all patients with available data (n = 74) experienced a median (IQR) percent reduction in PSA of 67.6% (52.3-82.2%). Only ten subjects (8.3%) experienced a Grade 3 adverse event; five were procedure-related. No Grade ≥ 4 AEs were reported. This study supports prior findings that IRE prostate ablation with the NanoKnife System can be performed safely. Final results are required to fully assess oncological, functional, and safety outcomes.

Dense surface reconstruction using a learning-based monocular vSLAM model for laparoscopic surgery.

Augmented reality (AR) has seen increased interest and attention for its application in surgical procedures. AR-guided surgical systems can overlay segmented anatomy from pre-operative imaging onto the user's environment to delineate hard-to-see structures and subsurface lesions intraoperatively. While previous works have utilized pre-operative imaging such as computed tomography or magnetic resonance images, registration methods still lack the ability to accurately register deformable anatomical structures without fiducial markers across modalities and dimensionalities. This is especially true of minimally invasive abdominal surgical techniques, which often employ a monocular laparoscope, due to inherent limitations. Surgical scene reconstruction is a critical component towards accurate registrations needed for AR-guided surgery and other downstream AR applications such as remote assistance or surgical simulation. In this work, we utilize a state-of-the-art (SOTA) deep-learning-based visual simultaneous localization and mapping (vSLAM) algorithm to generate a dense 3D reconstruction with camera pose estimations and depth maps from video obtained with a monocular laparoscope. The proposed method can robustly reconstruct surgical scenes using real-time data and provide camera pose estimations without stereo or additional sensors, which increases its usability and is less intrusive. We also demonstrate a framework to evaluate current vSLAM algorithms on non-Lambertian, low-texture surfaces and explore using its outputs on downstream tasks. We expect these evaluation methods can be utilized for the continual refinement of newer algorithms for AR-guided surgery.

Feature Extraction of Ultrasound Radiofrequency Data for the Classification of the Peripheral Zone of Human Prostate.

Prostate cancer ranks among the most prevalent types of cancer in males, prompting a demand for early detection and noninvasive diagnostic techniques. This paper explores the potential of ultrasound radiofrequency (RF) data to study different anatomic zones of the prostate. The study leverages RF data's capacity to capture nuanced acoustic information from clinical transducers. The research focuses on the peripheral zone due to its high susceptibility to cancer. The feasibility of utilizing RF data for classification is evaluated using ex-vivo whole prostate specimens from human patients. Ultrasound data, acquired using a phased array transducer, is processed, and correlated with B-mode images. A range filter is applied to highlight the peripheral zone's distinct features, observed in both RF data and 3D plots. Radiomic features were extracted from RF data to enhance tissue characterization and segmentation. The study demonstrated RF data's ability to differentiate tissue structures and emphasizes its potential for prostate tissue classification, addressing the current limitations of ultrasound imaging for prostate management. These findings advocate for the integration of RF data into ultrasound diagnostics, potentially transforming prostate cancer diagnosis and management in the future.

An augmented reality-guided biopsy system using a high-speed motion tracking and real-time registration platform.

Biopsies play a crucial role in diagnosis of various diseases including cancers. In this study, we developed an augmented reality (AR) system to improve biopsy procedures and increase targeting accuracy. Our AR-guided biopsy system uses a high-speed motion tracking technology and an AR headset to display a holographic representation of the organ, lesions, and other structures of interest superimposed on real physical objects. The first application of our AR system is prostate biopsy. By incorporating preoperative scans, such as computed tomography (CT) or magnetic resonance imaging (MRI), into real-time ultrasound-guided procedures, this innovative AR-guided system enables clinicians to see the lesion as well as the organs in real time. With the enhanced visualization of the prostate, lesion, and surrounding organs, surgeons can perform prostate biopsies with an increased accuracy. Our AR-guided biopsy system yielded an average targeting accuracy of 2.94 ± 1.04 mm and can be applied for real-time guidance of prostate biopsy as well as other biopsy procedures.

An augmented reality and high-speed optical tracking system for laparoscopic surgery.

While minimally invasive laparoscopic surgery can help reduce blood loss, reduce hospital time, and shorten recovery time compared to open surgery, it has the disadvantages of limited field of view and difficulty in locating subsurface targets. Our proposed solution applies an augmented reality (AR) system to overlay pre-operative images, such as those from magnetic resonance imaging (MRI), onto the target organ in the user's real-world environment. Our system can provide critical information regarding the location of subsurface lesions to guide surgical procedures in real time. An infrared motion tracking camera system was employed to obtain real-time position data of the patient and surgical instruments. To perform hologram registration, fiducial markers were used to track and map virtual coordinates to the real world. In this study, phantom models of each organ were constructed to test the reliability and accuracy of the AR-guided laparoscopic system. Root mean square error (RMSE) was used to evaluate the targeting accuracy of the laparoscopic interventional procedure. Our results demonstrated a registration error of 2.42 ± 0.79 mm and a procedural targeting error of 4.17 ± 1.63 mm using our AR-guided laparoscopic system that will be further refined for potential clinical procedures.

A dual-camera hyperspectral laparoscopic imaging system.

Minimally invasive surgery (MIS) has expanded broadly in the field of abdominal and pelvic surgery. However, there are still prevalent issues surrounding intracorporeal surgery, such as iatrogenic injury, anastomotic leakage, or the presence of positive tumor margins after resection. Current approaches to address these issues and advance laparoscopic imaging techniques often involve fluorescence imaging agents, such as indocyanine green (ICG), to improve visualization, but these have drawbacks. Hyperspectral imaging (HSI) is an emerging optical imaging modality that takes advantage of spectral characteristics of different tissues. Various applications include tissue classification and digital pathology. In this study, we developed a dual-camera system for high-speed hyperspectral imaging. This includes the development of a custom application interface and corresponding hardware setup. Characterization of the system was performed, including spectral accuracy and spatial resolution, showing little sacrifice in speed for the approximate doubling of the covered spectral range, with our system acquiring 29 spectral images from 460-850 nm. Reference color tiles with various reflectance profiles were imaged and a RMSE of 3.56 ± 1.36% was achieved. Sub-millimeter resolution was shown at 7 cm working distance for both hyperspectral cameras. Finally, we image ex vivo tissues, including porcine stomach, liver, intestine, and kidney with our system and use a high-resolution, radiometrically calibrated spectrometer for comparison and evaluation of spectral fidelity. The dual-camera hyperspectral laparoscopic imaging system can have immediate applications in various surgeries.

Retzius-sparing vs. posterior urethral suspension: similar early-phase post-robotic radical prostatectomy continence outcomes.

Stress urinary incontinence (SUI) is a risk of robotic-assisted radical prostatectomy (RP) which can be a frustrating problem for both surgeons and patients. We aim to compare short-term continence outcomes between patients undergoing Retzius Sparing RP (RS-RP) and those undergoing standard RP with the inclusion of a PUS suture technique and suprapubic tube (PUS-RP). A retrospective review of 105 consecutive patients who underwent RP was performed, comparing patients who underwent RS-RP and PUS-RP. Our main outcome was pad usage as a surrogate for SUI. Patients were evaluated 4 weeks following RP and again at approximately 3 months. Continence was defined as no pad usage or up to one safety pad per day. Risk factors associated with not being continent were identified using univariate and multivariate analyses. In our cohort, 52 patients underwent RS-RP and 53 patients underwent PUS-RP. The two groups had similar patient demographics. Although not statistically significant, there was a higher rate of a positive surgical margin in the RS-RP compared to PUS-RP (25% vs 15%, p = 0.204). At one month follow-up for PUS-RP and RS-RP, there was no significant difference in the frequency of continent men (69.2% vs. 76.9%, p = 0.302). At 3-month follow-up for the two groups of patients, again, there was no significant difference in the frequency of continence for PUS-RP and RS-RP (86.2% vs 88%, p = 0.824). Patients who underwent RS-RP had similar rates of continence to those patients undergoing PUS-RP in the short-term post-operative period.

Mapping Cellular Interactions from Spatially Resolved Transcriptomics Data.

Cell-cell communication (CCC) is essential to how life forms and functions. However, accurate, high-throughput mapping of how expression of all genes in one cell affects expression of all genes in another cell is made possible only recently, through the introduction of spatially resolved transcriptomics technologies (SRTs), especially those that achieve single cell resolution. However, significant challenges remain to analyze such highly complex data properly. Here, we introduce a Bayesian multi-instance learning framework, spacia, to detect CCCs from data generated by SRTs, by uniquely exploiting their spatial modality. We highlight spacia's power to overcome fundamental limitations of popular analytical tools for inference of CCCs, including losing single-cell resolution, limited to ligand-receptor relationships and prior interaction databases, high false positive rates, and most importantly the lack of consideration of the multiple-sender-to-one-receiver paradigm. We evaluated the fitness of spacia for all three commercialized single cell resolution ST technologies: MERSCOPE/Vizgen, CosMx/Nanostring, and Xenium/10X. Spacia unveiled how endothelial cells, fibroblasts and B cells in the tumor microenvironment contribute to Epithelial-Mesenchymal Transition and lineage plasticity in prostate cancer cells. We deployed spacia in a set of pan-cancer datasets and showed that B cells also participate in PDL1/PD1 signaling in tumors. We demonstrated that a CD8+ T cell/PDL1 effectiveness signature derived from spacia analyses is associated with patient survival and response to immune checkpoint inhibitor treatments in 3,354 patients. We revealed differential spatial interaction patterns between γδ T cells and liver hepatocytes in healthy and cancerous contexts. Overall, spacia represents a notable step in advancing quantitative theories of cellular communications.

Evaluating robotic-assisted partial nephrectomy surgeons with fully convolutional segmentation and multi-task attention networks.

We use machine learning to evaluate surgical skill from videos during the tumor resection and renography steps of a robotic assisted partial nephrectomy (RAPN). This expands previous work using synthetic tissue to include actual surgeries. We investigate cascaded neural networks for predicting surgical proficiency scores (OSATS and GEARS) from RAPN videos recorded from the DaVinci system. The semantic segmentation task generates a mask and tracks the various surgical instruments. The movements from the instruments found via semantic segmentation are processed by a scoring network that regresses (predicts) GEARS and OSATS scoring for each subcategory. Overall, the model performs well for many subcategories such as force sensitivity and knowledge of instruments of GEARS and OSATS scoring, but can suffer from false positives and negatives that would not be expected of human raters. This is mainly attributed to limited training data variability and sparsity.

Optimal Prostate Cancer Diagnostic Pathways for Men With Prostatomegaly in the MRI Era.

OBJECTIVE: To evaluate utilities of multiparametric MRI and targeted biopsy to detect clinically significant prostate cancer in men with prostatomegaly. MATERIALS AND METHODS: We conducted a retrospective review of multiparametric MRI obtained for elevated PSA between 2017 and 2020. We selected patients with prostates ≥80 g who had undergone biopsy. Clinically significant prostate cancer was defined as grade group ≥2. Predictive and logistic regression analyses quantified impacts of diagnostic components. RESULTS: A total of 338 patients met inclusion criteria: 89 (26.3%) had clinically significant prostate cancer. On MRI, positive predictive value for clinically significant prostate cancer was 26.5% for PIRADS 4% and 73.5% for PIRADS 5; negative predictive value for MRI without suspicious lesions was 98.8%. Applying PSA density to MRI yielded a negative predictive value of 78.9% for PIRADS 4 lesions at PSA density <0.05 and a positive predictive value of 90.5% for PIRADS 5 lesions at PSA density ≥0.15. Targeted (versus standard) biopsy reduced likelihood of missing clinically significant prostate cancer by >50% (12.2% vs 28.3%). MRI in-bore biopsies trended towards better accuracy versus MRI-transrectal ultrasound fusion biopsies (75% versus 52%). On logistic regression analyses, MRI improved predictive accuracy (area under the curve 0.91), and PIRADS score demonstrated the strongest association with clinically significant prostate cancer (odds ratio 6.42, P < .001). CONCLUSION: For large prostates, MRI is less predictive of clinically significant prostate cancer but effectively rules out malignancy. PSA density better informs biopsy decisions for PIRADS 4 and 5 lesions. There may be a pronounced role for targeted biopsy, specifically in-bore, in prostatomegaly.

Phase 2 Trial of Stereotactic Ablative Radiotherapy for Patients with Primary Renal Cancer.

BACKGROUND: Most renal cell carcinomas (RCCs) are localized and managed by active surveillance, surgery, or minimally invasive techniques. Stereotactic ablative radiation (SAbR) may provide an innovative non-invasive alternative although prospective data are limited. OBJECTIVE: To investigate whether SAbR is effective in the management of primary RCCs. DESIGN, SETTING, AND PARTICIPANTS: Patients with biopsy-confirmed radiographically enlarging primary RCC (≤5 cm) were enrolled. SAbR was delivered in either three (12 Gy) or five (8 Gy) fractions. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary endpoint was local control (LC) defined as a reduction in tumor growth rate (compared with a benchmark of 4 mm/yr on active surveillance) and pathologic evidence of tumor response at 1 yr. Secondary endpoints included LC by the Response Evaluation Criteria in Solid Tumors (RECIST 1.1), safety, and preservation of kidney function. Exploratory tumor cell-enriched spatial protein and gene expression analysis were conducted on pre- and post-treatment biopsy samples. RESULTS AND LIMITATIONS: Target accrual was reached with the enrollment of 16 ethnically diverse patients. Radiographic LC at 1 yr was observed in 94% of patients (15/16; 95% confidence interval: 70, 100), and this was accompanied by pathologic evidence of tumor response (hyalinization, necrosis, and reduced tumor cellularity) in all patients. By RECIST, 100% of the sites remained without progression at 1 yr. The median pretreatment growth rate was 0.8 cm/yr (interquartile range [IQR]: 0.3, 1.4), and the median post-treatment growth rate was 0.0 cm/yr (IQR: -0.4, 0.1, p < 0.002). Tumor cell viability decreased from 4.6% to 0.7% at 1 yr (p = 0.004). With a median follow-up of 36 mo for censored patients, the disease control rate was 94%. SAbR was well tolerated with no grade ≥2 (acute or late) toxicities. The average glomerular filtration rate declined from a baseline of 65.6 to 55.4 ml/min at 1 yr (p = 0.003). Spatial protein and gene expression analyses were consistent with the induction of cellular senescence by radiation. CONCLUSIONS: This clinical trial adds to the growing body of evidence suggesting that SAbR is effective for primary RCC supporting its evaluation in comparative phase 3 clinical trials. PATIENT SUMMARY: In this clinical trial, we investigated a noninvasive treatment option of stereotactic radiation therapy for the treatment of primary kidney cancer and found that it was safe and effective.

A High-Speed Hyperspectral Laparoscopic Imaging System.

Minimally invasive surgery (MIS) has expanded broadly in the field of abdominal and pelvic surgery. Laparoscopic and robotic surgery has improved surgeon ergonomics, instrument precision, operative time, and postoperative recovery across various abdominal procedures. The goal of this study is to establish the feasibility of implementing high-speed hyperspectral imaging into a standard laparoscopic setup and exploring its benefit to common intracorporeal procedures. A hyperspectral laparoscopic imaging system was constructed using a customized hyperspectral camera alongside a standard rigid laparoscope and was validated for both spectral and spatial accuracy. Demosaicing methods were investigated for improved full-resolution visualization. Hyperspectral cameras with different spectral ranges were considered and compared with one another alongside two different light sources to determine the most effective configuration. Finally, different porcine tissues were imaged ex-vivo to test the capabilities of the system and spectral footprints of the various tissues were extracted. The tissue was also imaged in a phantom to simulate the system's use in MIS. The results demonstrated a hyperspectral laparoscopic imaging system that could provide quantitative, diagnostic information while not disrupting normal workflow nor adding excessive weight to the laparoscopic setup. The high-speed hyperspectral laparoscopic imaging system can have immediate applications in image-guided surgery.

Evaluating Surgical Outcomes of Robot Assisted Simple Prostatectomy in the Retreatment Setting.

OBJECTIVE: To report perioperative and postoperative outcomes in men who undergo salvage RASP (sRASP) following some other endoscopic outlet procedure for benign prostate enlargement (BPE) compared to those undergoing RASP for primary treatment (pRASP). METHODS: A prospectively maintained database consisting of all RASP surgeries (December 2014-October 2019) performed at our institution by 3 different urologists was used. Patients who had received an endoscopic procedure for BPE prior to their RASP (sRASP) were compared to those who had not had a prior outlet procedure (pRASP). RESULTS: In total, 310 men underwent RASP during the study period. Of those, 30 (9.7%) had undergone an endoscopic procedure prior to surgery. There were no significant differences in age, race, ASA, BMI, prostate volume, PSA or rates of preoperative retention (P> .05 for all). Men who were treatment-naive had significantly higher preoperative International Prostate Symptom Scores (IPSS) than men who had a prior procedure (18.3 ± 7.7 vs 13.6 ± 6.2, P = .008). However, there were no significant differences in functional or quality of life outcomes between the 2 groups (P > .05 for all). There were no significant differences in perioperative or post-operative outcomes between the 2 groups. Furthermore, rates of post-operative complications and incontinence were similar between groups (11% vs 10%, P = .9 and 2% vs 0%, P = 1 respectively). CONCLUSION: Performing a RASP after prior endoscopic procedure for BPE was found to be safe and effective. Success and complication rates were similar to patients with no prior procedures.

PSA density is associated with BPH cellular composition.

BACKGROUND: Current AUA guidelines recommend 5 alpha reductase inhibitor (5ARI) treatment for patients with obstructive benign prostatic hyperplasia (BPH) that display prostate volume ≥30 cc and total prostate specific antigen (PSA) ≥1.5 ng/ml. However, BPH is highly pleomorphic and response to 5ARIs is highly variable. An understanding of cellular composition based on a noninvasive PSA density test could lead to improved clinical decision making. METHODS: The histological composition of 307 BPH specimens was scored by a pathologist for stromo-glandular content and associated with total PSA, prostate volume, PSA density and other clinical variables using univariate and multivariate linear regression. RESULTS: The percentage of glandular composition in prostates of 5ARI-naïve men was positively and independently associated with PSA and PSA density. It was determined through statistical modeling that a PSA density ≤0.05 ng/ml2 associated with a glandular composition of ≤30% with 76% sensitivity. CONCLUSIONS: PSA density could provide a decisive variable for estimating BPH cellular content and may eventually improve selection of patients for 5ARI treatment. Further work is needed to demonstrate that patients with higher glandular content are more responsive to 5ARI treatment.

Safety and Feasibility of Telehealth Only Preoperative Evaluation Before Minimally Invasive Robotic Urologic Surgery.

Purpose: Telehealth utilization has increased dramatically over the past few years due to improvement in technology and the COVID-19 pandemic. To date, no study has examined whether a telehealth visit alone for preoperative evaluation is safe and sufficient before surgery. We examined the safety and feasibility of preoperative telehealth visits alone before minimally invasive urologic surgery. Materials and Methods: Single institution retrospective review of robotic prostate, kidney, and cystectomy procedures between April and December 2020. Cases were dichotomized into those who underwent preoperative evaluation by telehealth only vs traditional in-person visits. Outcomes included complications, blood loss, conversion to open surgery rates, and operative times. We assessed efficiency of care by measuring time from preoperative visit to surgery. Results: Three hundred fourteen patients were included in the study, with 14% of cases (n = 45) being performed after a preoperative telehealth visit. The majority of cases included in analysis were robotic surgeries of the prostate (56.1% of all cases, n = 176) and the kidney (35.0% of all cases, n = 110). Patients seen via telehealth alone preoperatively had no significant differences in any grade of complications, perioperative outcomes, blood loss, operative time, and length of stay. There was no difference in change in anticipated procedure between the groups, and there was no case of conversion to open surgery in the telehealth only group. Time from preoperative visit to surgery was significantly shorter for the telehealth group by 13 days. Conclusions: Our study is the first to analyze the safety of telehealth only preoperative visits before minimally invasive urologic surgery. We found no difference in perioperative outcomes including conversion to open surgery or change in planned procedure. Furthermore, telehealth preoperative visits appeared to facilitate shorter time to surgery. This study has important implications for expediting patient care and medicolegal considerations.

Identifying predictors of antispasmodic use following robotic assisted simple prostatectomy.

INTRODUCTION: Anticholinergic or ß-3 agonist use following robotic simple prostatectomy (RASP) is not well described. We describe rates of antispasmodic use following RASP and identify potential predictors of medication use. MATERIALS AND METHODS: A retrospective review of all RASP patients from 2/2016 - 1/2020 was conducted. Patients with no preoperative International Prostate Symptom Score (IPSS) were excluded. Demographics, clinical data, and postoperative medication use were collected by electronic medical record review. Multivariable logistic regression analysis using a priori variables was performed to identify independent factors associated with antispasmodic use. RESULTS: A total of 255 patients underwent RASP at a mean age of 70.0 years ± 7.3 and mean body mass index (BMI) of 28.6 kg/m2 ± 5.0. Median preoperative prostate volume was 132.3 cc ± 45.0. Rates of preoperative diabetes, obstructive sleep apnea (OSA), smoking and alcohol use were 19.6%, 6.3%, 3.1%, and 11.8% respectively; 8.6% of patients (n = 22) initiated antispasmodics at a median of 2.5 months (IQR 1.3-4.2) postoperatively. Median duration of antispasmodic use was 6.5 months (IQR 1.7-14.7). Mirabegron was most commonly prescribed (31.8%). On multivariable logistic regression analysis, OSA was independently associated with postoperative antispasmodic use (OR 8.13, 95% CI 2.02-32.67, p = 0.003); 68.8% of OSA patients were treated with continuous positive airway pressure (CPAP). Treatment was not significantly associated with postoperative antispasmodic use (p = 0.61). CONCLUSION: Patients with OSA are over 8 times more likely to require antispasmodic medications following RASP in the short term. These patients may benefit from more tailored preoperative counseling.

Single-port robotic-assisted simple prostatectomy is associated with decreased post-operative narcotic use in a propensity score matched analysis.

Robotic-assisted simple prostatectomy (RASP) has proven to be an effective minimally invasive option for benign prostatic enlargement (BPE) in recent years. Single-site surgery is theorized to reduce post-operative pain beyond traditional minimally invasive approaches. We sought to assess whether use of a single-port robotic platform decreases post-operative opioid use in patients undergoing robotic-assisted simple prostatectomy (RASP). A retrospective review was performed of all patients undergoing RASP our institution from November 2017 to July 2019. Demographic, intraoperative, and post-operative data, including morphine equivalent (ME) use, were collected. Patients were stratified by robotic platform utilized. Propensity score matching using nearest neighbor method was performed using prostate volume, Charlson comorbidity index (CCI), and post-op ketorolac use in 4:1 fashion. Chi-squared analysis and Kruskal-Wallis analyses were utilized. Two-hundred-and-seven men underwent RASP. After matching, 80 patients (64 multi-port, 16 single-port) were included in the analysis. Groups were comparable for age, body mass index, CCI, prostate volume, prior opioid use, and use of scheduled ketorolac post op. The single-port approach was associated with a reduction in MEs once admitted to the floor (5 vs. 11 mg, p = 0.025) and an increase in the proportion of patients who did not require any narcotics post-operatively (44 vs. 19%, p = 0.036). In a propensity matched cohort of patients undergoing RASP at a single institution, use of the single-port robotic system conferred a significant decrease in post-operative narcotic use by approximately 50%.

A low-cost PVC-based dual-modality kidney phantom.

Phantoms are invaluable tools broadly used for research and training purposes designed to mimic tissues and structures in the body. In this paper, polyvinyl chloride (PVC)-plasticizer and silicone rubbers were explored as economical materials to reliably create long-lasting, realistic kidney phantoms with contrast under both ultrasound (US) and X-ray imaging. The radiodensity properties of varying formulations of soft PVC-based gels were characterized to allow adjustable image intensity and contrast. Using this data, a phantom creation workflow was established which can be easily adapted to match radiodensity values of other organs and soft tissues in the body. Internal kidney structures such as the medulla and ureter were created using a two-part molding process to allow greater phantom customization. The kidney phantoms were imaged under US and X-ray scanners to compare the contrast enhancement of a PVC-based medulla versus a silicone-based medulla. Silicone was found to have higher attenuation than plastic under X-ray imaging, but poor quality under US imaging. PVC was found to exhibit good contrast under X-ray imaging and excellent performance for US imaging. Finally, the durability and shelf life of our PVC-based phantoms were observed to be vastly superior to that of common agar-based phantoms. The work presented here allows extended periods of usage and storage for each kidney phantom while simultaneously preserving anatomical detail, contrast under dual-modality imaging, and low cost of materials.

Clinical Outcomes of Robotic Assisted Partial Nephrectomy for Pathologic T3a Renal Masses With Venous Tumor Thrombus.

OBJECTIVE: To evaluate the safety, efficacy, and early oncologic outcomes of pathologic T3a (pT3a) renal cell carcinoma with venous involvement treated with robotic partial nephrectomy (RPN), given that experience and outcomes in this group is limited. METHODS: A retrospective chart review of patients undergoing RPN from September 2009 to July 2020 was performed. Outcomes were captured from patients with pT3a disease with vein involvement. Clinical characteristics were analyzed using SPSS (IBM, Armonk, NY). Local recurrence-free survival and metastasis-free survival at 2 years were calculated from Kaplan-Meier survival curves. RESULTS: For 45 included patients, mean operative and warm ischemia times were 199.6 ± 47.3 minutes and 30.5 ± 10.5 minutes, with mean estimated blood loss of 324.9 ± 209.5 cc. Rates of transfusion, embolization, re-admission, and re-operation at 30 days were 8.9% (4/45), 2.2% (1/45), 11.1% (5/45), and 6.7% (3/45; cystoscopic stent placement), respectively. All tumors were malignant on pathology, with clear cell renal cell carcinoma being the most common (91.0%, n = 41). The positive margin rate was 6.7% (n = 3). Local recurrence occurred in 4.4% (n = 2) at a mean time of 5.2 ± 2.3 months. Four patients (8.9%) progressed to metastatic disease at a mean of 22.2 ± 23.0 months. At 2 years, local recurrence-free survival was 95.4% and metastasis-free survival was 95.3%. CONCLUSION: We present the largest known series of patients RPN for pT3a renal masses with venous tumor involvement. We found it both feasible and safe in the appropriate hands. Short term oncologic outcomes for these patients appear more favorable than historic literature suggested.

MRI Features Associated with Histology of Benign Prostatic Hyperplasia Nodules: Generation of a Predictive Model.

Background: Histologic phenotypic variation of benign prostatic hyperplasia (BPH) has been hypothesized to underlie response to medical therapy. We evaluate preoperative MRI of robot-assisted simple prostatectomy (RASP) specimens and determine imaging features associated with histologic phenotype. Materials and Methods: All patients undergoing RASP from November 2015 to November 2019 with a multiparametric MRI ≤1 year before RASP were included. Patients without identifiable BPH nodules on histologic specimens were excluded. Histology slides were obtained from whole mount adenoma specimens and corresponding MRI were reviewed and graded independently by a blinded expert in BPH histopathology (D.W.S.) and an experienced radiologist specializing in prostate imaging (D.N.C.), respectively. Each nodule was assigned a phenotypic score on a 5-point Likert scale (1 = predominantly glandular; 5 = predominantly stromal) by each reviewer. Scores were compared using the sign test and univariate analysis. Signal intensity relative to background transition zone and nodule texture were noted on T2, diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging sequences. Univariate and multivariate stepwise linear regression analysis were conducted to identify MRI features associated with histology score. All analyses were performed using Statistical Analysis System (version 9.4). Results: A total of 99 prostate nodules in 29 patients were included. Median phenotypic scores by histology and MRI were comparable (2, interquartile range [IQR] 2-3 vs 2, IQR 2-4, respectively; p = 0.63). Histology scores were positively correlated with MRI scores (Pearson's correlation 0.84, p < 0.0001). Multivariate stepwise linear regression analysis showed that low apparent diffusion coefficient (ADC) signal intensity (p < 0.001) and DCE wash-in (p = 0.03) were positively associated with more stromal histology, whereas ADC standard deviation (p = 0.03), DCE wash-out (p = 0.001), and heterogeneous T2 texture (p = 0.003) were associated with more glandular histology. Conclusion: There is a strong correlation between MRI features and the histologic phenotype of BPH nodules. MRI may provide a noninvasive method to determine underlying BPH nodule histology.