Growth response of dental tissues to developmental stress in the domestic pig (Sus scrofa)

Objectives: To compare relative response of enamel, dentin and bone to developmental stressors between attritional and catastrophic mortality assemblages of pigs. Materials and methods: Heads from 70 Sus scrofa of known sex, weight and age comprising an attritional sample of 50 sick pen (SP) pigs that died prematurely versus 20 control pigs slaughtered at 6 months (Catastrophic assemblage). Hard tissue changes (alveolar bone thinning), abnormal bone formation (Harris lines) and re‐modeling (auditory bullae) were recorded. Areas and volumes of coronal enamel and dentin were recorded from microCT scans with Avizo 6.3 and Geomagic Wrap. Results: Attritional and catastrophic assemblages are metrically indistinguishable. Ages at death and tissue measures in the SP pigs are differentially distributed, necessitating partition into developmental outcome cohorts. SP “late death” pigs are of lesser physiological maturity than expected, free of disease, with large dental tissue dimensions, comparable to “Controls”. SP “early death” pigs have 5% less dentin and enamel and chronic bone infection. Older cohorts of the SP “early deaths” mortality assemblage show progressively reduced enamel. SP pigs show dental evidence of reduced bone mass in the maxilla. Discussion: Bone, dentin and enamel tissues, each, respond distinctively to developmental stressors. Bone mass evinces malnutrition not disease. Both dental tissue reduction and abnormal bone formation link to chronic infection. Paradoxically, reduced dentin mass signals lower survivorship while reduced enamel signals enhanced survivorship. Meaningful comparison of Attritional and Catastrophic assemblages necessitates recognition of developmental outcome cohorts, stratified by age at death and physiological maturity, to reveal heterogeneity of survivorship, tissue measures and lesions

New-onset atrial fibrillation in patients with worsening heart failure and coronary artery disease:an analysis from the COMMANDER-HF trial

Background: Atrial fibrillation (AF) in the presence of heart failure (HF) is associated with poor outcomes including a high-risk of stroke and other thromboembolic events. Identifying patients without AF who are at high-risk of developing this arrhythmia has important clinical implications. Aims: To develop a risk score to identify HF patients at high risk of developing AF. Methods: The COMMANDER-HF trial enrolled 5022 patients with HF and a LVEF ≤ 40%, history of coronary artery disease, and absence of AF at baseline (confirmed with an electrocardiogram). Patients were randomized to either rivaroxaban (2.5 mg bid) or placebo. New-onset AF was confirmed by the investigator at study visits. Results 241 (4.8%) patients developed AF during the follow-up (median 21 months). Older age (≥ 65 years), LVEF < 35%, history of PCI or CABG, White race, SBP < 110 mmHg, and higher BMI (≥ 25 kg/m2) were independently associated with risk of new-onset AF, whereas the use of DAPT was associated with a lower risk of new-onset AF. We then built a risk score from these variables (with good accuracy C-index = 0.71) and calibration across observed and predicted tertiles of risk. New-onset AF events rates increased steeply by increasing tertiles of the risk-score. Compared to tertile 1, the risk of new-onset AF was 2.5-fold higher in tertile 2, and 6.3-fold higher in tertile 3. Rivaroxaban had no effect in reducing new-onset AF. In time-updated models, new-onset AF was associated with a higher risk of subsequent all-cause death: HR (95%CI) 1.38 (1.11–1.73). Conclusions: A well-calibrated risk-score identified patients at risk of new-onset AF in the COMMANDER-HF trial. Patients who developed AF had a higher risk of subsequent death

Rivaroxaban in patients with heart failure, sinus rhythm, and coronary disease

Background: Heart failure is associated with activation of thrombin-related pathways, which predicts a poor prognosis. We hypothesized that treatment with rivaroxaban, a factor Xa inhibitor, could reduce thrombin generation and improve outcomes for patients with worsening chronic heart failure and underlying coronary artery disease. Methods: In this double-blind, randomized trial, 5022 patients who had chronic heart failure, a left ventricular ejection fraction of 40% or less, coronary artery disease, and elevated plasma concentrations of natriuretic peptides and who did not have atrial fibrillation were randomly assigned to receive rivaroxaban at a dose of 2.5 mg twice daily or placebo in addition to standard care after treatment for an episode of worsening heart failure. The primary efficacy outcome was the composite of death from any cause, myocardial infarction, or stroke. The principal safety outcome was fatal bleeding or bleeding into a critical space with a potential for causing permanent disability. Results: Over a median follow-up period of 21.1 months, the primary end point occurred in 626 (25.0%) of 2507 patients assigned to rivaroxaban and in 658 (26.2%) of 2515 patients assigned to placebo (hazard ratio, 0.94; 95% confidence interval [CI], 0.84 to 1.05; P=0.27). No significant difference in all-cause mortality was noted between the rivaroxaban group and the placebo group (21.8% and 22.1%, respectively; hazard ratio, 0.98; 95% CI, 0.87 to 1.10). The principal safety outcome occurred in 18 patients who took rivaroxaban and in 23 who took placebo (hazard ratio, 0.80; 95% CI, 0.43 to 1.49; P=0.48). Conclusions: Rivaroxaban at a dose of 2.5 mg twice daily was not associated with a significantly lower rate of death, myocardial infarction, or stroke than placebo among patients with worsening chronic heart failure, reduced left ventricular ejection fraction, coronary artery disease, and no atrial fibrillation. (Funded by Janssen Research and Development; COMMANDER HF ClinicalTrials.gov number, NCT01877915.

Diabetic foot ulcers segmentation challenge report: benchmark and analysis

Monitoring the healing progress of diabetic foot ulcers is a challenging process. Accurate segmentation of foot ulcers can help podiatrists to quantitatively measure the size of wound regions to assist prediction of healing status. The main challenge in this field is the lack of publicly available manual delineation, which can be time consuming and laborious. Recently, methods based on deep learning have shown excellent results in automatic segmentation of medical images, however, they require large-scale datasets for training, and there is limited consensus on which methods perform the best. The 2022 Diabetic Foot Ulcers segmentation challenge was held in conjunction with the 2022 International Conference on Medical Image Computing and Computer Assisted Intervention, which sought to address these issues and stimulate progress in this research domain. A training set of 2000 images exhibiting diabetic foot ulcers was released with corresponding segmentation ground truth masks. Of the 72 (approved) requests from 47 countries, 26 teams used this data to develop fully automated systems to predict the true segmentation masks on a test set of 2000 images, with the corresponding ground truth segmentation masks kept private. Predictions from participating teams were scored and ranked according to their average Dice similarity coefficient of the ground truth masks and prediction masks. The winning team achieved a Dice of 0.7287 for diabetic foot ulcer segmentation. This challenge has now entered a live leaderboard stage where it serves as a challenging benchmark for diabetic foot ulcer segmentation

Natriuretic peptide-based inclusion criteria in a heart failure clinical trial: insights from COMMANDER HF

Objectives: This study investigated the effects of a mid-trial protocol amendment requiring elevated natriuretic peptides for inclusion in the COMMANDER-HF (A Study to Assess the Effectiveness and Safety of Rivaroxaban in Reducing the Risk of Death, Myocardial Infarction, or Stroke in Participants with Heart Failure and Coronary Artery Disease Following an Episode of Decompensated Heart Failure) trial. Background: Heart failure (HF) trials that select patients based on history of HF hospitalization alone are susceptible to regional variations in event rates. Elevated plasma concentrations of natriuretic peptides (NPs) as selection criteria may help HF ascertainment and risk enrichment. In the COMMANDER-HF trial, B-type natriuretic peptide greater than or equal to 200 ng/l or N-terminal pro–B-type natriuretic peptide greater than or equal to 800 ng/l were added to inclusion criteria as a mid-trial protocol amendment, providing a unique case-study of NP-based inclusion criteria. Methods: We compared the baseline characteristics, event rates, and treatment effects for patients enrolled before and after the NP protocol amendment. The primary endpoint was all-cause death, myocardial infarction, or stroke. Secondary endpoints included HF rehospitalization and cardiovascular death. Results: A total of 5,022 patients with left ventricular ejection fraction less than or equal to 40% and coronary artery disease were included. Compared to patients enrolled before the NP protocol amendment, those enrolled post-amendment (n = 3,867, 77%) were older, more often had diabetes, and had lower values for body mass index, left ventricular ejection fraction, and estimated glomerular filtration rate, higher heart rate, and higher event rates: primary endpoint (hazard ratio [HR]: 1.32; 95% confidence interval [CI]: 1.16 to 1.50), cardiovascular death (HR: 1.29; 95% CI: 1.11 to 1.50), HF rehospitalization (HR: 1.31; 95% CI: 1.15 to 1.49), and major bleeding (HR: 1.71; 95% CI: 1.11 to 2.65). Differences between pre- and post-amendment rates were confined to and driven by Eastern Europe. This protocol amendment did not modify the neutral effect of rivaroxaban on the primary endpoint (p interaction = 0.36) or secondary endpoints. Conclusions: In a global event-driven trial of rivaroxaban in HF, requiring elevated NPs for inclusion increased event rates allowing earlier completion of the trial but did not modify treatment effect. These data inform future HF trials regarding the expected impact of NP-based inclusion criteria on patient characteristics and event rates. (COMMANDER HF [A Study to Assess the Effectiveness and Safety of Rivaroxaban in Reducing the Risk of Death, Myocardial Infarction, or Stroke in Participants With Heart Failure and Coronary Artery Disease Following an Episode of Decompensated Heart Failure] NCT01877915

Temperature detection based on nonparametric statistics of ultrasound echoes

Different ultrasound echoes properties have been used for the noninvasive temperature monitoring. Temperature variations that occur during heating/cooling process induce changes in a random process of ultrasound backscattering. It was already proved that the probability distribution of the backscattered RF (radio frequency) signals is sensitive to the temperature variations. Contrary to previously used methods which explored models of scattering and involved techniques of fitting histograms to a special probability distribution two more direct measures of changes in statistics are proposed in this paper as temperature markers. They measure the ''distance'' between the probability distributions. The markers are the Kolmogorov Smirnov distance and Kulback-Leiber divergence. The feasibility of using such nonparametric statistics for non- invasive ultrasound temperature estimation is demonstrated on the ultrasounds data collected during series of heating experiments in which the temperature was independently registered by the classical thermometer or thermocouples

Using Empirical Mode Decomposition of Backscattered Ultrasound Signal Power Spectrum for Assessment of Tissue Compression

Quantitative ultrasound has been widely used for tissue characterization. In this paper we propose a new approach for tissue compression assessment. The proposed method employs the relation between the tissue scatterers’ local spatial distribution and the resulting frequency power spectrum of the backscattered ultrasonic signal. We show that due to spatial distribution of the scatterers, the power spectrum exhibits characteristic variations. These variations can be extracted using the empirical mode decomposition and analyzed. Validation of our approach is performed by simulations and in-vitro experiments using a tissue sample under compression. The scatterers in the compressed tissue sample approach each other and consequently, the power spectrum of the backscattered signal is modified. We present how to assess this phenomenon with our method. The proposed in this paper approach is general and may provide useful information on tissue scattering properties

A spectral-based method for tissue characterization

Quantitative ultrasound methods are widely investigated as a promising tool for tissue characterization. In this paper, a novel quantitative method is developed which can be used to assess scattering properties of tissues. The proposed method is based on analysis of oscillations of the backscattered echo power spectrum. It is shown that these oscillations of the power spectrum are connected with the distances between scatterers within the medium. Two techniques are proposed to assess the scatterer’s distribution. First, we show that the inverse Fourier transform of the backscattered echo power spectrum corresponds to a histogram of the distances between scatterers. Second, the Hilbert-Huang transform is used to directly extract the power spectrum oscillations. Both methods are examined by means of a numerical experiment. A cellular gas model of a biological medium is considered. Results are presented and discussed. Both methods can be used to evaluate the scatterer’s distribution by means of the power spectrum oscillations