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DOI: 10.1148/radiol.2482072016
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(Radiology 2008;248:1004-1012.)
© RSNA, 2008

Technical Developments

Left Ventricle: Automated Segmentation by Using Myocardial Effusion Threshold Reduction and Intravoxel Computation at MR Imaging1

Noel C. F. Codella, MEng, Jonathan W. Weinsaft, MD, Matthew D. Cham, MD, Matthew Janik, MD, Martin R. Prince, MD, PhD, and Yi Wang, PhD

1 From the Department of Physiology, Biophysics, and Systems Biology (N.C.F.C., Y.W.), Department of Radiology (J.W.W., M.D.C., M.J., M.R.P., Y.W.), and Cardiology Division, Department of Medicine (J.W.W., M.J.), Weill Medical College of Cornell University, 575 Lexington Ave, 3rd Floor, New York, NY. Received November 18, 2007; revision requested January 4, 2008; revision received January 9; accepted February 20; final version accepted March 3. Address correspondence to Y.W. (e-mail: yiwang{at}med.cornell.edu).

This retrospective analysis of existing patient data had institutional review board approval and was performed in compliance with HIPAA. No informed consent was required. The purpose of the study was to develop and validate an algorithm for automated segmentation of the left ventricular (LV) cavity that accounts for papillary and/or trabecular muscles and partial voxels in cine magnetic resonance (MR) images, an algorithm called LV Myocardial Effusion Threshold Reduction with Intravoxel Computation (LV-METRIC). The algorithm was validated in biologic phantoms, and its results were compared with those of manual tracing, as well as those of a commercial automated segmentation software (MASS [MR Analytical Software System]), in 38 subjects. LV-METRIC accuracy in vitro was 98.7%. Among the 38 subjects studied, LV-METRIC and MASS ejection fraction estimations were highly correlated with manual tracing (R2 = 0.97 and R2 = 0.95, respectively). Ventricular volume estimations were smaller with LV-METRIC and larger with MASS than those calculated by using manual tracing, though all results were well correlated (R2 = 0.99). LV-METRIC volume measurements without partial voxel interpolation were statistically equivalent to manual tracing results (P > .05). LV-METRIC had reduced intraobserver and interobserver variability compared with other methods. MASS required additional manual intervention in 58% of cases, whereas LV-METRIC required no additional corrections. LV-METRIC reliably and reproducibly measured LV volumes.

Supplemental material: http://radiology.rsnajnls.org/cgi/content/full/248/3/1004/DC1

© RSNA, 2008