3D reconstruction of rib cage geometry from biplanar radiographs using a statistical parametric model approach

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. This is an author-deposited version published in: https://sam.ensam.eu Handle ID AbstractRib cage 3D reconstruction is an important prerequisite for thoracic spine modelling, particularly for studies of the deformed thorax in adolescent idiopathic scoliosis. This study proposes a new method for rib cage 3D reconstruction from biplanar radiographs, using a statistical parametric model approach.Simplified parametric models were defined at the hierarchical levels of rib cage surface, rib midline and rib surface, and applied on a database of 86 trunks. The resulting parameter database served to statistical models learning which were used to quickly provide a first estimate of the reconstruction from identifications on both radiographs. This solution was then refined by manual adjustments in order to improve the matching between model and image. Accuracy was assessed by comparison with 29 rib cages from CT scans in terms of geometrical parameter differences and in terms of line-to-line error distance between the rib midlines. Intra and inter-observer reproducibility were determined regarding 20 scoliotic patients.The first estimate (mean reconstruction time of 2'30) was sufficient to extract the main rib cage global parameters with a 95% confidence interval lower than 7%, 8%, 2% and 4° for rib cage volume, antero-posterior and lateral maximal diameters and maximal rib hump, respectively. The mean error distance was 5.4 mm (max 35mm) down to 3.6 mm (max 24 mm) after the manual adjustment step (+3'30).The proposed method will improve developments of rib cage finite element modeling and evaluation of clinical outcomes.

Determination of a new uniform thorax density representative of the living population from 3D external body shape modeling

“…The reconstruction of the rib cage allows estimation of the volume of trabecular bone and of the cortical bone for each rib level and for each participant based on the rib length (Aubert et al, 2014) (Eq. (5)).…”

“…These bi-planar radiographies allow three dimensional (3D) reconstructions of the bones and human body shape using well documented models (Aubert et al, 2014;Humbert et al, 2009;Nérot et al, 2015) (Figs. 1 and 2).…”

“…A new low-dose imaging system taking bi-planar radiographies (Dubousset et al, 2010) combined with 3D reconstruction technique of the external body shape (Nérot et al, 2015), spine (Humbert et al, 2009) and of rib cage (Aubert et al, 2014) allows for volume estimation. Densities for each thorax tissues and segment have been well documented in the literature (Dempster, 1955;Erdmann and Gos, 1990;Hayashi et al, 2011;Li et al, 2010).…”

Evaluation of a Patient-Specific Finite-Element Model to Simulate Conservative Treatment in Adolescent Idiopathic Scoliosis

“…The precision (2RMS SD ) for measurement of vertebral position and orientation, and for calculation of clinical indices based on 3D reconstruction from biplanar radiographs have been previously determined [19,20] (Table 3). When comparing two 3D reconstructions, the minimal error that can be expected is [33].…”

“…For each patient, the three-dimensional geometry of the pelvis, spine and ribcage was reconstructed using previously described techniques [17][18][19][20][21][22] by experienced users. Briefly, these methods allow the personalization of parametric models of bony structures (vertebrae, ribs, pelvis), based on transversal and longitudinal inferences, to fit the radiographic images of the patient (postero-anterior and lateral).…”