Intensity-Based Nonoverlapping Area Registration Supporting "Drop-Outs" in Terms of Model-Based Radiostereometric Analysis.

Michal Spanel,Ondrej Klima,Roman Madeja,David Barina,Petr Novobilsky,Pavel Zemcik,Adam Chromy

doi:10.1155/2018/8538125

Abstract

A model-based radiostereometric analysis (MBRSA) is a method for precise measurement of prosthesis migration, which does not require marking the implant with tantalum beads. Instead, the prosthesis pose is typically recovered using a feature-based 2D-3D registration of its virtual model into a stereo pair of radiographs. In this study, we evaluate a novel intensity-based formulation of previously published nonoverlapping area (NOA) approach. The registration is capable of performing with both binary radiographic segmentations and nonsegmented X-ray images. In contrast with the feature-based version, it is capable of dealing with unreliable parts of prosthesis. As the straightforward formulation allows efficient acceleration using modern graphics adapters, it is possible to involve precise high-poly virtual models. Moreover, in case of binary segmentations, the nonoverlapping area is simply interpretable and useful for indicating the accuracy of the registration outcome. In silico and phantom evaluations were performed using a cementless Zweymüller femoral stem and its reverse engineered (RE) model. For initial pose estimates with difference from the ground-truth limited to ±4 mm and ±4°, respectively, the mean absolute translational error was not higher than 0.042 ± 0.035 mm. The error in rotation around the proximodistal axis was 0.181 ± 0.265°, and the error for the remaining axes was not higher than 0.035 ± 0.037°.

Highlights

Research ArticleIntensity-Based Nonoverlapping Area Registration Supporting “Drop-Outs” in Terms of Model-Based Radiostereometric Analysis
Radiostereometric analysis (RSA), introduced by Selvik [1, 2], is an established method for an accurate measurement of prosthesis mechanical stability, indicated in particular in cases of total joint arthroplasty. e analysis is used for measuring micromotion between the prosthesis and the surrounding bone
Due to its high precision, it allows to reveal a potential failure of the implant fixation at early stages, when the prosthesis migration is not recognizable in plain radiographs, nor clinical symptoms occur [3]. e conventional radiostereometric analysis depends on two sets of tantalum beads. e first set of markers is attached to the prosthesis, while the second set of beads is injected directly into a bone surrounding the implant. e position of each marker in three-dimensional space is obtained using a triangulation from a stereo pair of radiographs

Summary

Research Article

Intensity-Based Nonoverlapping Area Registration Supporting “Drop-Outs” in Terms of Model-Based Radiostereometric Analysis. A model-based radiostereometric analysis (MBRSA) is a method for precise measurement of prosthesis migration, which does not require marking the implant with tantalum beads. The prosthesis pose is typically recovered using a feature-based 2D-3D registration of its virtual model into a stereo pair of radiographs. We evaluate a novel intensity-based formulation of previously published nonoverlapping area (NOA) approach. E registration is capable of performing with both binary radiographic segmentations and nonsegmented X-ray images. In contrast with the feature-based version, it is capable of dealing with unreliable parts of prosthesis. In case of binary segmentations, the nonoverlapping area is interpretable and useful for indicating the accuracy of the registration outcome. For initial pose estimates with difference from the ground-truth limited to ±4 mm and ±4°, respectively, the mean absolute translational error was not higher than 0.042 ± 0.035 mm. e error in rotation around the proximodistal axis was 0.181 ± 0.265°, and the error for the remaining axes was not higher than 0.035 ± 0.037°

Introduction

Results

Binary segmentations Equalized radiographs

Discussion and Conclusion