RV remodelling in PAH patients can be accurately assessed with both 3DE and CMR. Both modalities are robust and reproducible with CMR being more reproducible for measurements of EF and RV mass.

PAH leads to RA and RV dilatation and functional deterioration which are linked to an adverse clinical outcome. 3DE measurement of RA sphericity index may be a suitable index in predicting clinical deterioration of PAH patients.

Strain and strain rate deformation parameters based on Color Doppler Myocardial Imaging, and more recently on two-dimensional (2D) gray scale images, have evolved as important methods for the quantification of myocardial function. Although these parameters are already applicable in the research field, their acquisition and analysis involve a number of technical challenges and complexities. Accurate knowledge of the basic principles of those techniques, as presented in this article, will further enhance their applicability to clinical practice.

SUMMARYThis paper is concerned with a novel version of the INAR(1) model, a non-linear auto-regressive Markov chain on N, with innovations following a finite mixture distribution of m ≥ 1 Poisson laws. For m > 1, the stationary marginal probability distribution of the chain is overdispersed relative to a Poisson, thus making INAR(1) suitable for modeling time series of counts with arbitrary overdispersion. The one-step transition probability function of the chain is also a finite mixture, of m Poisson-Binomial laws, facilitating likelihood-based inference for model parameters. An explicit EM-algorithm is devised for inference by maximization of a conditional likelihood. Alternative options for inference are discussed along with criteria for selecting m. Integer-valued prediction (IP) is developed by a parametric bootstrap approach to 'coherent' forecasting, and a certain test statistic based on predictions is introduced for assessing performance of the fitted model. The proposed model is fitted to time series of counts of pixels where spatially averaged rain rate exceeds a given threshold level, illustrating its capabilities in challenging cases of highly overdispersed count data.