title: Shape-Constrained Multi-Atlas Segmentation of Spleen in CT.
abstract: Spleen segmentation on clinically acquired CT data is a challenging problem given the complicity and variability of abdominal anatomy. Multi-atlas segmentation is a potential method for robust estimation of spleen segmentations, but can be negatively impacted by registration errors. Although labeled atlases explicitly capture information related to feasible organ shapes, multi-atlas methods have largely used this information implicitly through registration. We propose to integrate a level set shape model into the traditional label fusion framework to create a shape-constrained multi-atlas segmentation framework. Briefly, we (1) adapt two alternative atlas-to-target registrations to obtain the loose bounds on the inner and outer boundaries of the spleen shape, (2) project the fusion estimate to registered shape models, and (3) convert the projected shape into shape priors. With the constraint of the shape prior, our proposed method offers a statistically significant improvement in spleen labeling accuracy with an increase in DSC by 0.06, a decrease in symmetric mean surface distance by 4.01 mm, and a decrease in symmetric Hausdorff surface distance by 23.21 mm when compared to a locally weighted vote (LWV) method.
authors.affiliation: Electrical Engineering, Vanderbilt University, Nashville, TN, USA 37235.
authors.forename: Zhoubing
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Computer Science, Vanderbilt University, Nashville, TN, USA 37235.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.affiliation: Electrical Engineering, Vanderbilt University, Nashville, TN, USA 37235.
authors.forename: Swetasudha
authors.initials: S
authors.lastname: Panda
authors.affiliation: Electrical Engineering, Vanderbilt University, Nashville, TN, USA 37235.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Asman
authors.affiliation: Institute of Imaging Science, Vanderbilt University, Nashville, TN USA 37235.
authors.forename: Kristen L
authors.initials: KL
authors.lastname: Merkle
authors.affiliation: Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA 37235.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Shanahan
authors.affiliation: Institute of Imaging Science, Vanderbilt University, Nashville, TN USA 37235 ; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA 37235.
authors.forename: Richard G
authors.initials: RG
authors.lastname: Abramson
authors.affiliation: Electrical Engineering, Vanderbilt University, Nashville, TN, USA 37235 ; Computer Science, Vanderbilt University, Nashville, TN, USA 37235 ; Institute of Imaging Science, Vanderbilt University, Nashville, TN USA 37235 ; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA 37235.
authors.forename: Bennett A
authors.initials: BA
authors.lastname: Landman
keywords: PCA; implicit shape model; multi-atlas segmentation; spleen segmentation