Computer-aided diagnosis of carotid atherosclerosis based on ultrasound image statistics, laws' texture and neural networks

Quantitative characterisation of carotid atherosclerosis and classification into symptomatic or asymptomatic is crucial in planning optimal treatment of atheromatous plaque. The computer-aided diagnosis (CAD) system described in this paper can analyse ultrasound (US) images of carotid artery and classify them into symptomatic or asymptomatic based on their echogenicity characteristics. The CAD system consists of three modules: a) the feature extraction module, where first-order statistical (FOS) features and Laws' texture energy can be estimated, b) the dimensionality reduction module, where the number of features can be reduced using analysis of variance (ANOVA), and c) the classifier module consisting of a neural network (NN) trained by a novel hybrid method based on genetic algorithms (GAs) along with the back propagation algorithm. The hybrid method is able to select the most robust features, to adjust automatically the NN architecture and to optimise the classification performance. The performance is measured by the accuracy, sensitivity, specificity and the area under the receiver-operating characteristic (ROC) curve. The CAD design and development is based on images from 54 symptomatic and 54 asymptomatic plaques. This study demonstrates the ability of a CAD system based on US image analysis and a hybrid trained NN to identify atheromatous plaques at high risk of stroke.

Autonomic stress responses elicited by watching a live broadcast soccer game: a pilot study

Aim: Increased rates of hospitalization due to cardiovascular events have been reported during phases of World Soccer Championships (WSC). The purpose of this pilot study was to explore acute psychological and physiological effects of watching a live broadcast soccer game during the WSC 2006. Methods: Seven male supporters (age: M=24; SD=2.7) of the Swiss National Soccer Team watched a game of their team in a controlled laboratory setting. Heart rate (HR), heart rate variability (HRV), salivary cortisol, alpha-amylase (sAA), and testosterone concentrations, as well as several mood ratings were captured repeatedly before, during, and after the game. Results: Subjects reported feeling stressed, and HR and sAA activity showed an increase during the game. In contrast, HRV, cortisol and testosterone were unaffected. Conclusion: Watching a sports competition seems to specifically affect the sympathetic nervous system, which can be measured by sensitive electrocardiographic and salivary markers.