PURPOSE: To find and verify the optimum sliding characteristics and material compressibility that provide the minimum error in deformable image registration of the lungs. METHODS: A deformable image registration study has been conducted on a total of 16 @entity2 @entity1 . @entity1 specific three dimensional finite element models have been developed to model left and right lungs, chest (body), and @entity5 based on 4D CT images. Contact surfaces have been applied to lung-chest cavity interfaces. Experimental test data are used to model nonlinear material properties of lungs. A parametric study is carried out on seven @entity1 , 20 conditions for each, to investigate the sliding behavior and the tissue compressibility of lungs. Three values of coefficient of friction of 0, 0.1, and 0.2 are investigated to model lubrication and sliding restriction on the lung-chest cavity interface. The effect of material compressibility of lungs is studied using Poisson's ratios of 0.35, 0.4, 0.45, and 0.499. The model accuracy is examined by calculating the difference between the image-based displacement of bronchial bifurcation points identified in the lung images and the calculated corresponding model-based displacement. Furthermore, additional bifurcation points around the @entity5 and its center of mass are used to examine the effect of the mentioned parameters on the @entity5 localization. RESULTS: The frictionless contact model with 0.4 Poisson's ratio provides the smallest residual errors of 1.1 +/- 0.9, 1.5 +/- 1.3, and 2.1 +/- 1.6 mm in the LR, AP, and SI directions, respectively. Similarly, this optimum model provides the most accurate location of the @entity5 with residual errors of 1.0 +/- 0.6, 0.9 +/- 0.7, and 1.4 +/- 1.0 mm in all three directions. The accuracy of this model is verified on an additional nine @entity1 with average errors of 0.8 +/- 0.7, 1.3 +/- 1.1, and 1.7 +/- 1.6 mm in the LR, AP, and SI directions, respectively. CONCLUSIONS: The optimum biomechanical model with the smallest registration error is when frictionless contact model and 0.4 Poisson's ratio are applied. The overall accuracies of all bifurcation points in all 16 @entity1 including @entity5 points are 1.0 +/- 0.7, 1.2 +/- 1.0, and 1.7 +/- 1.4 mm in the LR, AP, and SI directions, respectively.

Sliding characteristic and material compressibility of XXXX lung: parametric study and verification.

@entity1 :: ('9606', 'Species') :: ['patients', 'Patient'] @entity2 :: ('MESH:D008175', 'Disease') :: ['lung cancer'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor']
@entity1 :: (9606,Species) :: ['human']
