Network-Based Approach for Modeling and Analyzing Coronary Angiography

Significant intra-observer and inter-observer variability in the interpretation of coronary angiograms are reported. This variability is in part due to the common practices that rely on performing visual inspections by specialists (e.g., the thickness of coronaries). Quantitative Coronary Angiography (QCA) approaches are emerging to minimize observer's error and furthermore perform predictions and analysis on angiography images. However, QCA approaches suffer from the same problem as they mainly rely on performing visual inspections by utilizing image processing techniques. In this work, we propose an approach to model and analyze the entire cardiovascular tree as a complex network derived from coronary angiography images. This approach enables to analyze the graph structure of coronary arteries. We conduct the assessments of network integration, degree distribution, and controllability on a healthy and a diseased coronary angiogram. Through our discussion and assessments, we propose modeling the cardiovascular system as a complex network is an essential phase to fully automate the interpretation of coronary angiographic images. We show how network science can provide a new perspective to look at coronary angiograms

Estimation of coronary artery hyperemic blood flow based on arterial lumen volume using angiographic images

The purpose of this study is to develop a method to estimate the hyperemic blood flow in a coronary artery using the sum of the distal lumen volumes in a swine animal model. The limitations of visually assessing coronary artery disease are well known. These limitations are particularly important in intermediate coronary lesions where it is difficult to determine whether a particular lesion is the cause of ischemia. Therefore, a functional measure of stenosis severity is needed using angiographic image data. Coronary arteriography was performed in 10 swine (Yorkshire, 25–35 kg) after power injection of contrast material into the left main coronary artery. A densitometry technique was used to quantify regional flow and lumen volume in vivo after inducing hyperemia. Additionally, 3 swine hearts were casted and imaged post-mortem using cone-beam CT to obtain the lumen volume and the arterial length of corresponding coronary arteries. Using densitometry, the results showed that the stem hyperemic flow (Q) and the associated crown lumen volume (V) were related by Q = 159.08 V3/4 (r = 0.98, SEE = 10.59 ml/min). The stem hyperemic flow and the associated crown length (L) using cone-beam CT were related by Q = 2.89 L (r = 0.99, SEE = 8.72 ml/min). These results indicate that measured arterial branch lengths or lumen volumes can potentially be used to predict the expected hyperemic flow in an arterial tree. This, in conjunction with measured hyperemic flow in the presence of a stenosis, could be used to predict fractional flow reserve based entirely on angiographic data

A systematic review of the reporting of Data Monitoring Committees' roles, interim analysis and early termination in pediatric clinical trials

<p>Abstract</p> <p>Background</p> <p>Decisions about interim analysis and early stopping of clinical trials, as based on recommendations of Data Monitoring Committees (DMCs), have far reaching consequences for the scientific validity and clinical impact of a trial. Our aim was to evaluate the frequency and quality of the reporting on DMC composition and roles, interim analysis and early termination in pediatric trials.</p> <p>Methods</p> <p>We conducted a systematic review of randomized controlled clinical trials published from 2005 to 2007 in a sample of four general and four pediatric journals. We used full-text databases to identify trials which reported on DMCs, interim analysis or early termination, and included children or adolescents. Information was extracted on general trial characteristics, risk of bias, and a set of parameters regarding DMC composition and roles, interim analysis and early termination.</p> <p>Results</p> <p>110 of the 648 pediatric trials in this sample (17%) reported on DMC or interim analysis or early stopping, and were included; 68 from general and 42 from pediatric journals. The presence of DMCs was reported in 89 of the 110 included trials (81%); 62 papers, including 46 of the 89 that reported on DMCs (52%), also presented information about interim analysis. No paper adequately reported all DMC parameters, and nine (15%) reported all interim analysis details. Of 32 trials which terminated early, 22 (69%) did not report predefined stopping guidelines and 15 (47%) did not provide information on statistical monitoring methods.</p> <p>Conclusions</p> <p>Reporting on DMC composition and roles, on interim analysis results and on early termination of pediatric trials is incomplete and heterogeneous. We propose a minimal set of reporting parameters that will allow the reader to assess the validity of trial results.</p