Semi-automatic left-atrial segmentation from volumetric ultrasound using B-spline explicit active surfaces

Segmentation of the left atrium (LA) of the heart allows quantification of LA volume dynamics which can give insight into cardiac function. However, very little attention has been given to LA segmentation from 3D ultrasound (US), most efforts being focused on the segmentation of the left ventricle (LV). The B-spline explicit active surfaces (BEAS) framework has been shown to be a very robust and efficient methodology to perform LV segmentation. In this study, the BEAS framework was adapted to allow for semi-automatic segmentation of the LA endocardium, with little user input. The method was tested in 20 volumetric sequences of echocardiographic data from healthy subjects and the segmentation results were evaluated against manual reference delineations of the LA. Relevant LA morphological and functional parameters were derived from the segmented surfaces, in order to assess the performance of the proposed method on its clinical usage. The results showed that the modified BEAS framework is capable of accurate semi-automatic LA segmentation in 3D transthoracic US, providing reliable quantification of the LA morphology and function.