P2A-8 Fully Automatic Detection of Left Ventricular Long Axis and Mitral Valve Plane in 3D Echocardiography

Automated segmentation approaches for the left ventricle (LV) in real-time 3D echocardiography (RT3DE) often rely on manual initialization. So far, little effort has been put in automating the initialization procedure to get to a fully automatic segmentation approach We propose a fully automatic method for the detection of the LV long axis (LAX) and the mitral valve plane (MVP) over the full cardiac cycle, for the initialization of segmentation algorithms in 3DE. It assigns probabilities to candidate LV center points through a Hough transform for circles, and detects the LV LAX by combining dynamic programming detections on these probabilities in 3D and 2D + time, to obtain a time-continuous solution. Subsequently, the mitral valve plane is detected in a projection of the data on a plane through the previously detected LAX. The method easily adjusts to different acquisition routines and combines robustness with good accuracy and low computational costs. Automatic detection was evaluated using patient data acquired with the Fast Rotating Ultrasound (FRU-) transducer (11 patients) and with the Philips Sonos 7500 ultrasound system with the X4 matrix transducer (14 patients). For the FRU data, the LAX was estimated with a distance of 2.85 plusmn 1.70 mm (Av plusmn SD) and an angle of 5.25 plusmn 3.17 degrees; the mitral valve plane was estimated with a distance of -1.54 plusmn 4.31 mm. For the matrix data these distances were 1.96 plusmn 1.30 mm with an angle error of 5.95 plusmn 2.11 and -1.66 plusmn 5.27 mm for the mitral valve plane. These results confirm that the method is very well suitable for automatic detection of the LV LAX and MVP. It provides a basis for further automatic exploration of the LV and could therefore replace manual initialization of 3D segmentation approaches.