Assessing the cortical thickness of long bone shafts in children, using two-dimensional ultrasonic diffraction tomography

Abstract

Echography is one of the first-line techniques used in clinical practice to diagnose osteoarticular diseases in children. However, this technique involves the use of standard equipment, which is not adapted to the morphology or the acoustical properties of children's bones. In this study, we developed an ultrasonic tomography method for measuring the cortical thickness of children's long bones. Ultrasonic tomography gives cross-sectional images showing the spatial distribution of some of the physical components of an object, based on scattered ultrasound measurements. These measurements are carried out using variably dense sets of transmitter and receiver positions and various the wave frequencies. We solved this inverse scattering problem using a Born approximation, which yields an attractively simple linear relation between the object function and the scattered field, particularly in the far field. Experiments with a 2D-ring antenna show the applicability of the method and its various improvements to bone thickness imaging.

P3D-4 Two-Dimensional Ultrasonic Computed Tomography of Growing Bones

“…The algorithm of summation of the filtered back-projections can then be used with some signal processing refinements. Despite the artifacts and biases affecting the assessment of the shell thickness, the main result obtained will be a qualitative image of the cavity [6,7].…”

Imaging Internal Structure of Long Bones Using Wave Scattering Theory

“…A multistep compensation technique (Lasaygues et al 2004;Ouedraogo et al 2002) was also developed to enhance the reconstructed images, where the reflection tomography provided information on the shape of the object, and transmission tomography was used to invert for the spatial variations of the inner structure. By use of a 2-D ring antenna with mechanical and electronic steering systems, ultrasonic-tomographic techniques were used to image the cross section of human femur shafts and estimate the cortical thickness of long bone shafts in children (Lasaygues 2006;Lasaygues et al 2005). The difference between mechanical and acoustical measurements of thickness was ,0.5 mm (Lasaygues 2006).…”

“…By use of a 2-D ring antenna with mechanical and electronic steering systems, ultrasonic-tomographic techniques were used to image the cross section of human femur shafts and estimate the cortical thickness of long bone shafts in children (Lasaygues 2006;Lasaygues et al 2005). The difference between mechanical and acoustical measurements of thickness was ,0.5 mm (Lasaygues 2006). Furthermore, Lasaygues and Le Marrec (2008) applied the intercepting canonical body approximation (ICBA) to solve imaging problems involving material with high-impedance contrast with the surrounding medium.…”

Thin Bone Sample Assessment Using Ultrasonic Transmitted Signals Based on Wavelet Processing Method

“…Two types of reconstruction experiments along different directions have been attempted on bone imaging. Ultrasonic computed tomography (UCT) focusing on the radial measurement around the middle shaft of bones are applied in vitro to image the cross-section of femurs of children and estimate the cortical thickness using a 2D-ring antenna and mechanical and electronic steering systems (Lasaygues and Lefebvre, 2001;Lasaygues, 2006). While Zheng (2011) employs similar techniques and methods, yet acquires zero-offset data along the axial direction on the bone surfaces, reconstructs the image of sagittal plane of long bones, and particularly estimates the thickness of top cortical layer.…”