Performance of 3-Dimensional Echocardiography in Measuring Left Ventricular Volumes and Ejection Fraction : A Systematic Review and Meta-Analysis

The assessment of left ventricular (LV) volume and ejection fraction (EF) is vital to the practice of cardiology. These measures are used to inform prognosis in most cardiac patient populations, determine treatment decisions for a variety of therapies, and function as eligibility criteria in many clinical trials (1-5). Despite their importance, there is no consensus on the best method to routinely measure EF and volumes. Two-dimensional echocardiography (2DE) is the most ubiquitous tool for assessing LV size and systolic function. Measurement of EF is the most common reason for referring a patient for an echocardiogram (6). This test is noninvasive, portable, inexpensive, radiation free, and quick. It does not, however, provide reliable, reproducible, and accurate measures of EF or volumes (7). Traditionally, 2DE has used the method of disks to calculate LV volumes based on areas in only 2 imaging planes (6). This method is subject to errors due to foreshortening, poor endocardial definition, narrow echocardiographic windows, and assumptions about LV shape. Because it is able to image the entire heart in multiple planes and provides excellent endocardial definition, cardiac magnetic resonance (CMR) imaging has been used as the gold standard for measuring LV volumes and EF (8). Nevertheless, the expense, limited availability, and incompatibility with metallic hardware make CMR impractical for widespread clinical use. Three-dimensional echocardiography (3DE) uses recently developed matrix array echocardiographic probes to image the entire heart in ≤8 beats/min. As opposed to older 3D methods, “live” 3D datasets provide volumes with minimal post-processing. Some echocardiographic laboratories have embraced this technology for routine care and charge for it using a new billable Current Procedural Terminology code for 3DE (9). Yet, it is still unclear if 3DE offers an advantage over 2DE, and, if so, in which patients and with which specific techniques. In this era when new technology, especially in imaging, has escalated medical costs, advances like 3DE should be thoroughly evaluated before recommending their large-scale use (10). We, therefore, undertook this systematic review of the 3DE published reports to evaluate its performance compared with CMR and its utility over traditional 2D methods in calculating EF and volumes.