title: Automated Volumetric Breast Density derived by Shape and Appearance Modeling.
abstract: The image shape and texture (appearance) estimation designed for facial recognition is a novel and promising approach for application in breast imaging. The purpose of this study was to apply a shape and appearance model to automatically estimate percent breast fibroglandular volume(%FGV) using digital mammograms. We built a shape and appearance model using 2000 full-field digital mammograms from the San Francisco Mammography Registry with known%FGVmeasured by single energy absorptiometry method. An affine transformation was used to remove rotation, translation and scale. Principal Component Analysis (PCA) was applied to extract significant and uncorrelated components of%FGV. To build an appearance model, we transformed the breast images into the mean texture image by piecewise linear image transformation. Using PCA the image pixels grey-scale values were converted into a reduced set of the shape and texture features. The stepwise regression with forward selection and backward elimination was used to estimate the outcome%FGVwith shape and appearance features and other system parameters. The shape and appearance scores were found to correlate moderately to breast%FGV, dense tissue volume and actual breast volume, body mass index (BMI) and age. The highest Pearson correlation coefficient was equal 0.77 for the first shape PCA component and actual breast volume. The stepwise regression method with ten-fold cross-validation to predict%FGVfrom shape and appearance variables and other system outcome parameters generated a model with a correlation of r2= 0.8. In conclusion, a shape and appearance model demonstrated excellent feasibility to extract variables useful for automatic%FGVestimation. Further exploring and testing of this approach is warranted.
authors.affiliation: Dept. of Radiology & Biomedical Imaging, Univ. of California at San Francisco, 1 Irving Street, San Francisco, CA, USA 94122.
authors.forename: Serghei
authors.initials: S
authors.lastname: Malkov
authors.affiliation: Depts. of Medicine and Epidemiology and Biostatistics, Univ. of California at San Francisco, 4150 Clement St., San Francisco, CA, United States, 94121.
authors.forename: Karla
authors.initials: K
authors.lastname: Kerlikowske
authors.affiliation: Dept. of Radiology & Biomedical Imaging, Univ. of California at San Francisco, 1 Irving Street, San Francisco, CA, USA 94122.
authors.forename: John
authors.initials: J
authors.lastname: Shepherd
keywords: breast density; digital mammography; shape and appearance model
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