129 Three-dimensional (3D) echocardiography has been shown successful in accurate measurements of ventricular volume 1-4 and mass. 5 We have developed the CenterSurface method for measuring regional wall thickness from 3D reconstructions of the left ventricle (LV). This method extends the centerline method to 3D.This study was performed to evaluate the accuracy of this method for measurement of regional wall thickness in vitro and in vivo. METHODS Preparation of Phantoms for In Vitro Wall Thickness Measurement LV phantoms were prepared from 7 slices of processed ham ordered from the butcher to have uniform thickness (5, 6, 7, 8, 9, 12, and 13 mm; Figure 1). Each phantom had a rounded apex and single annulus at the base. The wall thickness of each phantom was verified with a microme- ter. One phantom varied from the specified thickness (6.1 mm instead of 6 mm). In 3 phantoms, the uniformity of wall thickness was assessed at 10 evenly distributed loca- tions and found to be 0.1 to 0.2 mm (SD around the mean wall thickness). Patient Population for In Vivo Wall Thickness Thirteen subjects (5 healthy and 8 with ischemia) were imaged using 3D echocardiography for evaluation of the accuracy of wall thickness measurement in vivo. Patient Population for In Vivo Wall Thickening Illustration The application of 3D echocardiography for analysis of regional function was illustrated, using the data of 2 addi- tional patients (1 with triple-vessel and 1 with single-vessel coronary artery disease) who were studied for an ongoing From the Cardiovascular Research and Training Center, University of Washington, Seattle; the Department of Cardiology, University Hospital, Clermont-Ferrand, France (J.L.); Cardiac Echo Labora- tory, St. Paul’s Hospital, Vancouver, British Columbia (B.M.); and Teaneck, NJ (S.R.M.). Supported in part by grants from NHLBI (HL41464), John L. Locke Charitable Trust (Seattle, Wash), Advanced Technologies Laboratory (Bothell, Wash), Washington Technology Center (Seattle), and University of Washington (Seattle). Reprint requests: Florence H. Sheehan, MD, University of Washington, Box 356422, Seattle, WA, 98195-6422. Copyright © 2002 by the American Society of Echocardiography. 0894-7317/2002/$35.00 + 0 27/1/118911 doi:10.1067/mje.2002.118911 Introduction: Three-dimensional (3D) echocardi- ography has been shown to accurately measure left ventricular (LV) volume and mass. This study evalu- ated the accuracy of 3D echocardiography and the CenterSurface method for measuring LV wall thick- ness in vitro and in vivo. Method: Three-dimensional echocardiography scans, obtained from 7 LV phantoms and subjects having healthy (n = 5) or diseased (n = 8) hearts, were digi- tized. Endocardial and epicardial borders were out- lined and used in 3D LV reconstruction. In vitro wall thickness was compared with true micrometer measurements. Three-dimensional in vivo wall thick- ness was compared with 2-dimensional (2D) thick- ness measured by the centerline method. Results: The in vitro 3D echocardiography measure- ments agreed closely with true wall thickness (P < .0001), as did in vivo measurements (P < .0001). Conclusion: Three-dimensional echocardiography reconstruction has previously been shown to pro- vide accurate representation of LV shape in addition to volume and mass. This study demonstrates that the CenterSurface method provides accurate quanti- fication of wall thickness. (J Am Soc Echocardiogr 2002;15:129-35.) Three-Dimensional Echocardiographic Measurement of Left Ventricular Wall Thickness: In Vitro and In Vivo Validation Michal Hubka, BS, Janusz Lipiecki, MD, Edward L. Bolson, MS, Roy W. Martin, PhD, Brad Munt, MD, Sharon R. Maza, MD, and Florence H. Sheehan, MD, Seattle, Washington; Clermont-Ferrand, France; Vancouver, British Columbia, Canada; and Teaneck, New Jersey