%0 Journal Article
%T A Digital Model to Simulate Effects of Bone Architecture Variations on Texture at Spatial Resolutions of CT, HR-pQCT, and ¦ÌCT Scanners
%A T. Lowitz
%A O. Museyko
%A V. Bousson
%A W. A. Kalender
%A J.-D. Laredo
%A K. Engelke
%J Journal of Medical Engineering
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/946574
%X The quantification of changes in the trabecular bone structure induced by musculoskeletal diseases like osteoarthritis, osteoporosis, rheumatoid arthritis, and others by means of a texture analysis is a valuable tool which is expected to improve the diagnosis and monitoring of a disease. The reaction of texture parameters on different alterations in the architecture of the fine trabecular network and inherent imaging factors such as spatial resolution or image noise has to be understood in detail to ensure an accurate and reliable determination of the current bone state. Therefore, a digital model for the quantitative analysis of cancellous bone structures was developed. Five parameters were used for texture analysis: entropy, global and local inhomogeneity, local anisotropy, and variogram slope. Various generic structural changes of cancellous bone were simulated for different spatial resolutions. Additionally, the dependence of the texture parameters on tissue mineralization and noise was investigated. The present work explains changes in texture parameter outcomes based on structural changes originating from structure modifications and reveals that a texture analysis could provide useful information for a trabecular bone analysis even at resolutions below the dimensions of single trabeculae. 1. Introduction Quantitative computed tomography (QCT) is an advanced method to measure bone mineral density (BMD) in vivo at various skeletal sites [1]. However, to date the in vivo quantitative analysis of the trabecular bone network remains challenging. For peripheral locations such as the distal radius or tibia dedicated high resolution peripheral QCT (HR-pQCT) equipment with an isotropic spatial resolution of about 130£¿ m exists [2], but long scan times result in frequent motion artifacts and disturb the analysis of trabecular bone structure [3, 4]. Analysis of the trabecular network imaged with in vivo techniques, predominantly not only with CT but also with MRI or X-ray films, has received a fair amount of attention in the past. In the majority of reported studies, binarization methods were used to separate bone from soft tissue prior to the calculation of histomorphometric parameters [5¨C7]. However, the spatial resolution of almost all in vivo imaging modalities exceeds the diameter of single trabeculae of about 100£¿ m to 200£¿ m [8¨C10]. Therefore, binarization techniques were avoided in the present work. Instead, texture parameters directly calculated from the gray value distribution of datasets were used. The texture analysis of trabecular bone is not a
%U http://www.hindawi.com/journals/jme/2014/946574/