A cubic B-spline-based hybrid registration of lung CT images for a dynamic airway geometric model with large deformation

Abstract

The goal of this study is to develop a matching algorithm that can handle large geometric changes in x-ray computed tomography (CT)-derived lung geometry occurring during deep breath maneuvers. These geometric relationships are further utilized to build a dynamic lung airway model for computational fluid dynamics (CFD) studies of pulmonary air flow. The proposed algorithm is based on a cubic B-spline-based hybrid registration framework that incorporates anatomic landmark information with intensity patterns. A sequence of invertible B-splines is composed in a multiresolution framework to ensure local invertibility of the large deformation transformation and a physiologically meaningful similarity measure is adopted to compensate for changes in voxel intensity due to inflation. Registrations are performed using the proposed approach to match six pairs of 3D CT human lung datasets. Results show that the proposed approach has the ability to match the intensity pattern and the anatomical landmarks, and ensure local invertibility for large deformation transformations. Statistical results also show that the proposed hybrid approach yields significantly improved results as compared with approaches using either landmarks or intensity alone.

Analysis of Three-Dimensional Aerosol Deposition in Pharmacologically Relevant Terms: Beyond Black or White ROIs

“…Parameterizing the affine by the global lung volume allowed estimation of blurring due to tidal breathing motion and also registration of the HRCT anatomy to the PET deposition images (Appendix II). Other methods have been used in the past to describe the displacement of landmarks between images (e.g., B-spline, (15,16) elastic-body spline, (17,18) thin-plate spline, (19,20) or moving least squares (21) ). There are also alternative semi-automatic methods to extract the displacement of points in the lung, (21,22) as well as image registration techniques.…”

“…There are also alternative semi-automatic methods to extract the displacement of points in the lung, (21,22) as well as image registration techniques. (16,23) The simple affine transformation applied to automatically detected bifurcations was successful in mapping intrapulmonary airways from TLC to MLV (see Fig. 1D) and made it possible to parameterize the function in a way that linearly transformed the airway tree with global lung volume in a way consistent with the HRCT images.…”

“…1D) and made it possible to parameterize the function in a way that linearly transformed the airway tree with global lung volume in a way consistent with the HRCT images. One of the alternative methods for modeling lung motion (16) assumes that each point of the tree moved along a line connecting the point in both images, where the position of point along the line was determined by the relative change in lung volume. If the motion of the airway tree did not include rotation, this method and the parameterized affine transformation would lead to similar results.…”

Deformable registration of the inflated and deflated lung in cone‐beam CT‐guided thoracic surgery: Initial investigation of a combined model‐ and image‐driven approach

“…Alternative methods have been investigated for registration under respiratory motion, taking advantage of anatomical landmarks and/or directly using image intensities to optimize various similarity metrics, such as those summarized and compared in the EMPIRE10 study. 18,[23][24][25] Considering the magnitude of deformations involved in registering the inflated and deflated lung, a combined, sequential approach was employed in the proposed method: first, a robust model-driven method matching the lung surface and airway bronchial trees between inflated and deflated states to achieve a fairly coarse localization of the target wedge (∼3-5 mm required localization accuracy); then, an intensity-corrected variant of the Demons algorithm refining registration to ∼1-2 mm accuracy to localize both the tumor and surrounding critical anatomy. An initial implementation of the proposed approach was previously introduced, 26 focusing on an alternative method employing simple surface correspondence, manual airway matching, and a preliminary assessment of intensity correction to address partial volume effects, tested on a single dataset.…”

3-D lung deformation and function from respiratory-gated 4-D x-ray CT images : application to radiation treatment planning.

“…Estimation of lung motion via matching of corresponding landmarks is possible once the airway/vessel bifurcations have been identified. However, warping models such as thin-plate spline [27,63,89], radial basis interpolation with the shift log function [101], and B-splines [125,156,196] need to be subsequently applied to permit computation of dense displacement fields.…”