doi:10.1016/j.ultrasmedbio.2005.03.016 ● Original Contribution SEGMENTATION OF REAL-TIME THREE-DIMENSIONAL ULTRASOUND FOR QUANTIFICATION OF VENTRICULAR FUNCTION: A CLINICAL STUDY ON RIGHT AND LEFT VENTRICLES ELSA D. ANGELINI,* SHUNICHI HOMMA, † GREGORY PEARSON, ‡ JEFFREY W. HOLMES, § and ANDREW F. LAINE § *Ecole Nationale Supérieure des Télécommunications, Paris, France; † Department of Medicine, Columbia University, New York, NY, USA; ‡ College of Physicians & Surgeons, Columbia University, New York, NY, USA; and § Department of Biomedical Engineering, Columbia University, New York, NY, USA (Received 28 July 2004, revised 14 March 2005, in final form 22 March 2005) Abstract—Among screening modalities, echocardiography is the fastest, least expensive and least invasive method for imaging the heart. A new generation of three-dimensional (3-D) ultrasound (US) technology has been developed with real-time 3-D (RT3-D) matrix phased-array transducers. These transducers allow interactive 3-D visualization of cardiac anatomy and fast ventricular volume estimation without tomographic interpolation as required with earlier 3-D US acquisition systems. However, real-time acquisition speed is performed at the cost of decreasing spatial resolution, leading to echocardiographic data with poor definition of anatomical structures and high levels of speckle noise. The poor quality of the US signal has limited the acceptance of RT3-D US technology in clinical practice, despite the wealth of information acquired by this system, far greater than with any other existing echocardiography screening modality. We present, in this work, a clinical study for segmen- tation of right and left ventricular volumes using RT3-D US. A preprocessing of the volumetric data sets was performed using spatiotemporal brushlet denoising, as presented in previous articles Two deformable-model segmentation methods were implemented in 2-D using a parametric formulation and in 3-D using an implicit formulation with a level set implementation for extraction of endocardial surfaces on denoised RT3-D US data. A complete and rigorous validation of the segmentation methods was carried out for quantification of left and right ventricular volumes and ejection fraction, including comparison of measurements with cardiac magnetic resonance imaging as the reference. Results for volume and ejection fraction measurements report good performance of quantification of cardiac function on RT3-D data compared with magnetic resonance imaging with better performance of semiautomatic segmentation methods than with manual tracing on the US data. (laine@columbia.edu) © 2005 World Federation for Ultrasound in Medicine & Biology. Key Words: Segmentation, Echocardiography, RT3-D, 3-D ultrasound, Level set, Denoising, Clinical study, LV, RV, Pulmonary hypertension. INTRODUCTION AND LITERATURE A reliable noninvasive imaging modality is essential for evaluating and monitoring patients with cardiac disease. Traditional screening techniques for quantitative assess- ment of cardiac function include multigated angiography (MUGA), magnetic resonance imaging (MRI), comput- erized tomography (CT), nuclear imaging and ultrasound (US). Among these modalities, US is the fastest, least expensive and least invasive screening modality for im- aging the heart. Because of the 3-D structure and defor- mation of the heart muscle during the cardiac cycle, analysis of irregularly shaped cardiac chambers or de- scription of valve morphology using 2-D images is in- herently limited. Developments in 3-D echocardiography started in the late 1980s with the introduction of offline 3-D medical US imaging systems. Many review articles have been published over the past decade, assessing the progress and limitations of 3-D US technology for clin- ical screening (Belohlavek et al. 1993; Fenster and Downey 2000; Ofili and Nanda 1994; Rankin et al. 1993). These articles reflect the diversity of 3-D systems that were developed for both image acquisition and re- construction, developed in three generations: 1. freehand Address correspondence to: Andrew F. Laine, D.Sc, Department of Biomedical Engineering, Columbia University, 416 CEPSR, MC8904, 530 West 120th street, New York, NY 10027 USA. E-mail: laine@columbia.edu Ultrasound in Med. & Biol., Vol. 31, No. 9, pp. 1143–1158, 2005 Copyright © 2005 World Federation for Ultrasound in Medicine & Biology Printed in the USA. All rights reserved 0301-5629/05/$–see front matter 1143