Super-resolution of clinical CT: Revealing microarchitecture in whole bone clinical CT image data.

Osteoporotic fractures, prevalent in the elderly, pose a significant health and economic burden. Current methods for predicting fracture risk, primarily relying on bone mineral density, provide only modest accuracy. If better spatial resolution of trabecular bone in a clinical scan were available, a more complete assessment of fracture risk would be obtained using microarchitectural measures of bone (i.e. trabecular thickness, trabecular spacing, bone volume fraction, etc.). However, increased resolution comes at the cost of increased radiation or can only be applied at small volumes of distal skeletal locations. This study explores super-resolution (SR) technology to enhance clinical CT scans of proximal femurs and better reveal the trabecular microarchitecture of bone. Using a deep-learning-based (i.e. subset of artificial intelligence) SR approach, low-resolution clinical CT images were upscaled to higher resolution and compared to corresponding MicroCT-derived images. SR-derived 2-dimensional microarchitectural measurements, such as degree of anisotropy, bone volume fraction, trabecular spacing, and trabecular thickness were within 16 % error compared to MicroCT data, whereas connectivity density exhibited larger error (as high as 1094 %). SR-derived 3-dimensional microarchitectural metrics exhibited errors <18 %. This work showcases the potential of SR technology to enhance clinical bone imaging and holds promise for improving fracture risk assessments and osteoporosis detection. Further research, including larger datasets and refined techniques, can advance SR's clinical utility, enabling comprehensive microstructural assessment across whole bones, thereby improving fracture risk predictions and patient-specific treatment strategies.

Temporally guided articulated hand pose tracking in surgical videos.

PURPOSE: Articulated hand pose tracking is an under-explored problem that carries the potential for use in an extensive number of applications, especially in the medical domain. With a robust and accurate tracking system on surgical videos, the motion dynamics and movement patterns of the hands can be captured and analyzed for many rich tasks. METHODS: In this work, we propose a novel hand pose estimation model, CondPose, which improves detection and tracking accuracy by incorporating a pose prior into its prediction. We show improvements over state-of-the-art methods which provide frame-wise independent predictions, by following a temporally guided approach that effectively leverages past predictions. RESULTS: We collect Surgical Hands, the first dataset that provides multi-instance articulated hand pose annotations for videos. Our dataset provides over 8.1k annotated hand poses from publicly available surgical videos and bounding boxes, pose annotations, and tracking IDs to enable multi-instance tracking. When evaluated on Surgical Hands, we show our method outperforms the state-of-the-art approach using mean Average Precision, to measure pose estimation accuracy, and Multiple Object Tracking Accuracy, to assess pose tracking performance. CONCLUSION: In comparison to a frame-wise independent strategy, we show greater performance in detecting and tracking hand poses and more substantial impact on localization accuracy. This has positive implications in generating more accurate representations of hands in the scene to be used for targeted downstream tasks.

The impact of team familiarity on intra and postoperative cardiac surgical outcomes.

BACKGROUND: Familiarity among cardiac surgery team members may be an important contributor to better outcomes and thus serve as a target for enhancing outcomes. METHODS: Adult cardiac surgical procedures (n = 4,445) involving intraoperative providers were evaluated at a tertiary hospital between 2016 and 2020. Team familiarity (mean of prior cardiac surgeries performed by participating surgeon/nonsurgeon pairs within 2 years before the operation) were regressed on cardiopulmonary bypass duration (primary-an intraoperative measure of care efficiency) and postoperative complication outcomes (major morbidity, mortality), adjusting for provider experience, surgeon 2-year case volume before the surgery, case start time, weekday, and perioperative risk factors. The relationship between team familiarity and outcomes was assessed across predicted risk strata. RESULTS: Median (interquartile range) cardiopulmonary bypass duration was 132 (91-192) minutes, and 698 (15.7%) patients developed major postoperative morbidity. The relationship between team familiarity and cardiopulmonary bypass duration significantly differed across predicted risk strata (P = .0001). High (relative to low) team familiarity was associated with reduced cardiopulmonary bypass duration for medium-risk (-24 minutes) and high-risk (-27 minutes) patients. Increasing team familiarity was not significantly associated with the odds of major morbidity and mortality. CONCLUSION: Team familiarity, which was predictive of improved intraoperative efficiency without compromising major postoperative outcomes, may serve as a novel quality improvement target in the setting of cardiac surgery.

Novel Assessments of Technical and Nontechnical Cardiac Surgery Quality: Protocol for a Mixed Methods Study.

BACKGROUND: Of the 150,000 patients annually undergoing coronary artery bypass grafting, 35% develop complications that increase mortality 5 fold and expenditure by 50%. Differences in patient risk and operative approach explain only 2% of hospital variations in some complications. The intraoperative phase remains understudied as a source of variation, despite its complexity and amenability to improvement. OBJECTIVE: The objectives of this study are to (1) investigate the relationship between peer assessments of intraoperative technical skills and nontechnical practices with risk-adjusted complication rates and (2) evaluate the feasibility of using computer-based metrics to automate the assessment of important intraoperative technical skills and nontechnical practices. METHODS: This multicenter study will use video recording, established peer assessment tools, electronic health record data, registry data, and a high-dimensional computer vision approach to (1) investigate the relationship between peer assessments of surgeon technical skills and variability in risk-adjusted patient adverse events; (2) investigate the relationship between peer assessments of intraoperative team-based nontechnical practices and variability in risk-adjusted patient adverse events; and (3) use quantitative and qualitative methods to explore the feasibility of using objective, data-driven, computer-based assessments to automate the measurement of important intraoperative determinants of risk-adjusted patient adverse events. RESULTS: The project has been funded by the National Heart, Lung and Blood Institute in 2019 (R01HL146619). Preliminary Institutional Review Board review has been completed at the University of Michigan by the Institutional Review Boards of the University of Michigan Medical School. CONCLUSIONS: We anticipate that this project will substantially increase our ability to assess determinants of variation in complication rates by specifically studying a surgeon's technical skills and operating room team member nontechnical practices. These findings may provide effective targets for future trials or quality improvement initiatives to enhance the quality and safety of cardiac surgical patient care. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/22536.

Repeated unpredictable threats without harm impair spatial working memory in the Barnes maze.

Psychological stressors elicit the anticipation of homeostatic challenge, whereas physical stressors are direct threats to homeostasis. Many rodent models of stress include both types of stressors, yet deficits, like those reported for working memory, are often attributed to psychological stress. To empirically test whether intermittent psychological stressors, such as repeated threats, are solely sufficient to impair spatial working memory, we developed a novel rodent model of stress that is restricted to the anticipation of threat, and free of direct physical challenge. Adolescent male Sprague-Dawley rats were randomly assigned to control (CT) or stress (ST) housing conditions consisting of two tub cages, one with food and another with water, separated by a tunnel. Over three weeks (P31-P52), the ST group received random (probability of 0.25), simultaneous presentations of ferret odor, and abrupt lights, and sound at the center of the tunnel. Relative to the CT group, the ST group had consistently fewer tunnel crossings, consistent with avoidance of a psychological stressor. Both groups had similar body weights and crossed the tunnel more in the dark than light period. Three days after removal from the treatment conditions, spatial working memory was tested on the Barnes maze. The ST group displayed deficits in spatial working memory, including longer latencies to enter the goal box position, and a greater number of returns to incorrect holes, but no significant differences in speed. Memory can be affected by sleep disruption, and sleep can be affected by stress. Circadian activity patterns in the tunnels were similar across groups. Therefore, the data suggest that intermittent threats without physical stress are sufficient to impair spatial working memory in adolescence.