Development and validation of the SickKids Enterprise-wide Data in Azure Repository (SEDAR).

Objectives: To describe the processes developed by The Hospital for Sick Children (SickKids) to enable utilization of electronic health record (EHR) data by creating sequentially transformed schemas for use across multiple user types. Methods: We used Microsoft Azure as the cloud service provider and named this effort the SickKids Enterprise-wide Data in Azure Repository (SEDAR). Epic Clarity data from on-premises was copied to a virtual network in Microsoft Azure. Three sequential schemas were developed. The Filtered Schema added a filter to retain only SickKids and valid patients. The Curated Schema created a data structure that was easier to navigate and query. Each table contained a logical unit such as patients, hospital encounters or laboratory tests. Data validation of randomly sampled observations in the Curated Schema was performed. The SK-OMOP Schema was designed to facilitate research and machine learning. Two individuals mapped medical elements to standard Observational Medical Outcomes Partnership (OMOP) concepts. Results: A copy of Clarity data was transferred to Microsoft Azure and updated each night using log shipping. The Filtered Schema and Curated Schema were implemented as stored procedures and executed each night with incremental updates or full loads. Data validation required up to 16 iterations for each Curated Schema table. OMOP concept mapping achieved at least 80 % coverage for each SK-OMOP table. Conclusions: We described our experience in creating three sequential schemas to address different EHR data access requirements. Future work should consider replicating this approach at other institutions to determine whether approaches are generalizable.

Comparing the Hospital Frailty Risk Score and the Clinical Frailty Scale Among Older Adults With Chronic Obstructive Pulmonary Disease Exacerbation.

Importance: Frailty is associated with severe morbidity and mortality among people with chronic obstructive pulmonary disease (COPD). Interventions such as pulmonary rehabilitation can treat and reverse frailty, yet frailty is not routinely measured in pulmonary clinical practice. It is unclear how population-based administrative data tools to screen for frailty compare with standard bedside assessments in this population. Objective: To determine the agreement between the Hospital Frailty Risk Score (HFRS) and the Clinical Frailty Scale (CFS) among hospitalized individuals with COPD and to determine the sensitivity and specificity of the HFRS (vs CFS) to detect frailty. Design, Setting, and Participants: A cross-sectional study was conducted among hospitalized patients with COPD exacerbation. The study was conducted in the respiratory ward of a single tertiary care academic hospital (The Ottawa Hospital, Ottawa, Ontario, Canada). Participants included consenting adult inpatients who were admitted with a diagnosis of acute COPD exacerbation from December 2016 to June 2019 and who used a clinical care pathway for COPD. There were no specific exclusion criteria. Data analysis was performed in March 2022. Exposure: Degree of frailty measured by the CFS. Main Outcomes and Measures: The HFRS was calculated using hospital administrative data. Primary outcomes were the sensitivity and specificity of the HFRS to detect frail and nonfrail individuals according to CFS assessments of frailty, and the secondary outcome was the optimal probability threshold of the HFRS to discriminate frail and nonfrail individuals. Results: Among 99 patients with COPD exacerbation (mean [SD] age, 70.6 [9.5] years; 56 women [57%]), 14 (14%) were not frail, 33 (33%) were vulnerable, 18 (18%) were mildly frail, and 34 (34%) were moderately to severely frail by the CFS. The HFRS (vs CFS) had a sensitivity of 27% and specificity of 93% to detect frail vs nonfrail individuals. The optimal probability threshold for the HFRS was 1.4 points or higher. The corresponding sensitivity to detect frailty was 69%, and the specificity was 57%. Conclusions and Relevance: In this cross-sectional study, using the population-based HFRS to screen for frailty yielded poor detection of frailty among hospitalized patients with COPD compared with the bedside CFS. These findings suggest that use of the HFRS in this population may result in important missed opportunities to identify and provide early intervention for frailty, such as pulmonary rehabilitation.

Algorithms for left atrial wall segmentation and thickness - Evaluation on an open-source CT and MRI image database.

Structural changes to the wall of the left atrium are known to occur with conditions that predispose to Atrial fibrillation. Imaging studies have demonstrated that these changes may be detected non-invasively. An important indicator of this structural change is the wall's thickness. Present studies have commonly measured the wall thickness at few discrete locations. Dense measurements with computer algorithms may be possible on cardiac scans of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). The task is challenging as the atrial wall is a thin tissue and the imaging resolution is a limiting factor. It is unclear how accurate algorithms may get and how they compare in this new emerging area. We approached this problem of comparability with the Segmentation of Left Atrial Wall for Thickness (SLAWT) challenge organised in conjunction with MICCAI 2016 conference. This manuscript presents the algorithms that had participated and evaluation strategies for comparing them on the challenge image database that is now open-source. The image database consisted of cardiac CT (n=10) and MRI (n=10) of healthy and diseased subjects. A total of 6 algorithms were evaluated with different metrics, with 3 algorithms in each modality. Segmentation of the wall with algorithms was found to be feasible in both modalities. There was generally a lack of accuracy in the algorithms and inter-rater differences showed that algorithms could do better. Benchmarks were determined and algorithms were ranked to allow future algorithms to be ranked alongside the state-of-the-art techniques presented in this work. A mean atlas was also constructed from both modalities to illustrate the variation in thickness within this small cohort.

Shape complexes: the intersection of label orderings and star convexity constraints in continuous max-flow medical image segmentation.

Optimization-based segmentation approaches deriving from discrete graph-cuts and continuous max-flow have become increasingly nuanced, allowing for topological and geometric constraints on the resulting segmentation while retaining global optimality. However, these two considerations, topological and geometric, have yet to be combined in a unified manner. The concept of "shape complexes," which combine geodesic star convexity with extendable continuous max-flow solvers, is presented. These shape complexes allow more complicated shapes to be created through the use of multiple labels and super-labels, with geodesic star convexity governed by a topological ordering. These problems can be optimized using extendable continuous max-flow solvers. Previous approaches required computationally expensive coordinate system warping, which are ill-defined and ambiguous in the general case. These shape complexes are demonstrated in a set of synthetic images as well as vessel segmentation in ultrasound, valve segmentation in ultrasound, and atrial wall segmentation from contrast-enhanced CT. Shape complexes represent an extendable tool alongside other continuous max-flow methods that may be suitable for a wide range of medical image segmentation problems.

Effect of Left Atrial Wall Thickness on Radiofrequency Ablation Success.

INTRODUCTION: Radiofrequency (RF) ablation in thicker regions of the left atrium (LA) may require increased ablation energy in order to achieve effective transmural lesions. Consequently, many cases of recurrent atrial fibrillation (AF) postablation may be due to thicker-than-normal atrial tissue. The aim of this study was to test the hypotheses that patients with recurrent AF have thicker tissue overall and that electrical reconnection is more likely in regions of thicker tissue. METHODS AND RESULTS: Retrospective analysis was performed on 86 CT images acquired preoperatively from a cohort of 119 patients who had undergone RF ablation for AF. Of these, 33 patients experienced recurrence of AF within 1 year of initial treatment and 29 returned for a repeat ablation. For each patient, LA wall thickness (LAWT) was measured from the images in 12 anatomical regions using custom software. Patients with recurrent AF had larger LAWT compared to successfully treated patients (1.6 ± 0.6 mm vs. 1.5 ± 0.5 mm, P < 0.001) and reconnection was found to be at regions of thicker tissue (1.6 ± 0.6 mm, P = 0.038) compared to nonreconnected regions (1.5 ± 0.5 mm). The superior right posterior wall of the LA was significantly related to both recurrence (P = 0.048) and reconnection (P = 0.014). CONCLUSION: Increased LAWT has a small but significant effect on postablation recurrence and reconnection. Measures of LAWT may facilitate appropriate dosing of RF energy, but other factors will be critical in transmural lesion formation and ablation success.

Automated planning of computer assisted mosaic arthroplasty.

We describe and evaluate a computer algorithm that automatically develops a surgical plan for computer assisted mosaic arthroplasty, a technically demanding procedure in which a set of osteochondral plugs are transplanted from a non-load-bearing area of the joint to the site of a cartilage defect. We found that the algorithm produced plans that were at least as good as a human expert, had less variability, and took less time.

Prediction of the repair surface over cartilage defects: a comparison of three methods in a sheep model.

Defects in articular cartilage can be repaired through osteochondral transplantation (mosaic arthroplasty), where osteochondral plugs from non-weight-bearing areas of the joint are transferred to the defect site. Incongruity between the plug surface and the adjacent cartilage results in increased contact pressures and poorer outcomes. We compare three methods to predict the desired repair surface for use in computer-assisted mosaic arthroplasty: manual estimation, a cubic spline surface, and a statistical shape atlas of the knee. The cubic spline was found to most accurately match the pre-impact cartilage surface; the atlas was found to match least accurately.

[Adverse reaction after use of latanoprost in Japanese glaucoma patients].

PURPOSE: Although latanoprost has proven to have a strong hypotensive effect, some patients show adverse reactions such as eyelid pigmentation, iridial pigmentation, or hypertrichosis. We prospectively investigated these adverse reactions. SUBJECTS AND METHODS: One hundred and one Japanese glaucoma or ocular hypertension patients were included. Iridial, eyelid, and eyelash photographs were taken before and at 6 months after latanoprost treatment. Increased eyelid pigmentation, iridial pigmentation, eyelash pigmentation, vellus hair of the lid, and hypertrichosis were assessed from these photographs. The correlation between the incidence of these adverse reactions and the time of instillation, type of glaucoma, sex, age, or concomitantly used eye drops, and the overlap of these were evaluated. RESULTS: Increased pigmentation of the eyelid was found in 6 cases(5.9%), of the iris in 32 cases (31.7%), of the eyelashes in 29 cases (28.7%), vellus hair of the lid in 38 cases(37.6%), and hypertrichosis in 51 cases(50.5%). Pigmentation of the eyelid was more frequently observed in patients who used latanoprost concomitantly (16.7%) than in those who did not use anti-glaucomatous eye drops before latanoprost treatment (1.6%), or in those treated with latanoprost who had switched from other anti-glaucomatous eye drops (6.3%) (p= 0.03). CONCLUSIONS: The incidence of adverse reactions caused by latanoprost was higher in the eyelashes and iris than in the eyelid.

Fast assessment of acetabular coverage using stereoscopic volume rendering.

Previous CT-based methods of measuring acetabular coverage of the femoral head have either been labor-intensive or have required extensive preprocessing of the data prior to visualization. We propose a method of measuring acetabular coverage using stereoscopic digitally reconstructed radiographs that required very little labor or image preprocessing time. Taking a craniocaudal view of the pelvis, we measured both preoperative and postoperative CTs of 10 patients treated with transtrochanteric periacetabular osteotomy. Measurements were then made in both monocular and stereoscopic rendering modes. Our method is fast, easy, and provides an intuitive means of visualizing an orthopedic parameter that is important in the progression of early hip arthritis.

Corneal endothelial cell morphology in patients undergoing cataract surgery.

PURPOSE: To evaluate the effect of age, gender, axial length, and presence of type II diabetes on corneal endothelial cell morphology in patients undergoing cataract surgery. METHODS: The corneal endothelial cell morphology was investigated in 1,819 eyes of 1,394 patients before cataract surgery. The parameters examined include cell density, coefficient of variation of cell area, and percentage of hexagonal cells. The effects of age, gender, axial length, and presence of type II diabetes on these parameters were evaluated. RESULTS: The mean values in endothelial cell density, coefficient of variation of cell area, and percentage of hexagonal cells in all eyes, were 2,543 +/- 254 cells/mm2 (range, 1906-3,252), 0.64 +/- 0.10 (range, 0.34-1.00), and 37.9 +/- 7.1% (range, 17.6-61.7), respectively. Stepwise multiple regression analysis revealed that age was the only explanatory variable to be relevant to corneal endothelial cell density (R = -0.201, p < 0.0001), coefficient of variation of cell area (R = 0.066, p = 0.0046), and percentage of hexagonal cells (R = -0.086, p = 0.0002). The other variables, including gender, axial length, and presence of type II diabetes mellitus, were found to be irrelevant to any of the parameters of corneal endothelial cells. CONCLUSIONS: Age is the major relevant factor in corneal endothelial cell morphology in patients before cataract surgery.