IPA97 SPECIAL SECTION zyxwvu Cardiac left ventricular volume changes assessment by long axis echocardiographical image processing zy S.K.Setarehdan J . J. So rag han zyxwvutsrqpon Indexing terms: Image processing, Edge detection, Biomedical engineering zyxwvutsrq Abstract: zyxwvutsrqp The authors describe a new fully automatic algorithm for left ventricular (LV) volume change measurement and assessment from both 2-chamber and 4-chamber apical views of echocardiographic images based on the American Society of Echocardiography (ASE) recommendations. The method identifies the left ventricular endocardium (LVE) in a ‘centre- based’ approach. In this approach the left ventricular centre point (LVCP) is firstly approximated using a robust fuzzy based technique. The LVE edge points are then searched for on nonuniform distributed radial lines emanating from the LVCP using a multiresolution edge detection technique based on the global maximum of wavelet transform (GMWT). The extracted edge points are then spatially/temporally processed to identify the final smooth boundary using cubic-B-splines. The extracted LVEs in a complete cardiac cycle, together with the standard approximating formula, are then used to compute the LV volume evolution in a cardiac cycle. Experiments with real two-dimensional echocardiographic images are presented. The accuracy of the GMWT edge detection technique, which is the heart of the system, is compared to the conventional Sobel and Laplace edge operators. 1 Introduction Measurement of left ventricular performance is a criti- cal step in the evaluation and management of almost all patients with suspected or clinically evident heart failure. Virtually all of the indices of the left ventricular pump performance are derived from measurement of volume and pressure. The indices derived from volume measurements such as the left ventricular end-diastole volume (EDV), end-systole volume (ESV), stroke zyxwvu 0 IEE, 1998 IEE Proceedings online no. 19982084 Paper first received 12th December 1997 and in revised form 9th April 1998 The authors are with the Signal Processing Division, Department of Elec- tronic and Electrical Engineering, University of Strathclyde, Glasgow, UK volume (SV) and ejection fraction (EF) have proved to be of greatest clinical v,alue [l]. Traditionally this has required cardiac catheterisation and left ventricular angiography. Different cardiac imaging modalities including MRI, CT scanners, radio-nuclide ventriculog- raphy, positron emittled tomography (PET) and echocardiography have also been extensively used to measure these volumes in the past. In [2] and [3] the effectiveness of echocardiography for real-time accurate determination of LV volumes and EF was reported. Other advantages of ultrasound imaging are the absence of the ionising mdiations, noninvasivity, porta- bility, reproducibility, low cost and also real-time processing. These make the standard echocardiography a very attractive technique for quantitative analysis of cardiac function compared to other modalities. zyx a L b Fig. 1 a Biplane modified Simpson’s rule for LV volume measurement using both the apical 2-chamber (left) and 4-chamber (right) views b.Single plane area-length method For LV volume measurement using only one view V = 0.85 zyxwvutsrq A2/L L zyxwvu v volume measurement A number of standard methods for LV volume meas- urement from 2DEs are recommended by the American Society of Echocardiography (ASE) based on the dimensions and area measurements in the images [4]. 203 IEE ProcVis. Image Signal Process., Vol. 145, No. 3, June I998