Examinando por Autor "Minonzio, Jean-Gabriel"

Mostrando 1 - 4 de 4
  • Miniatura
    Ítem
    Bi-directional Axial Transmission measurements is an easy to apply methodology allowing risk assessment of fracture in elderly
    (Hal Open Science, 2020) Minonzio, Jean-Gabriel; Ramiandrisoa, Donatien; Schneider, Johannes; Kohut, Eva; Streichhahn, Melanie; Stervbo, Ulrik; Wirth, Rainer; Westhoff, Timm; Raum, Kay; Babel, Nina
    Accurate measurement of cortical bone parameters may improve fracture risk assessment and help clinicians on the best treatment strategy. The objective of this crosssectional study was to evaluate the performance of a Bi-Directional Axial Transmission (BDAT) device used by trained operators in a clinical environment with elderly subjects. The device, positioned at one-third distal radius, provides two velocities: VFAS (first arriving signal) and VA0 (first anti-symmetrical guided mode). Moreover, two parameters are obtained from an inverse approach: Ct.Th (cortical thickness) and Ct.Po (cortical porosity). The areal bone mineral density (aBMD) was obtained using DXA at the femur and spine. Eighty seven (65 women, 22 men) from Marien Hospital and St. Anna Hospital (Herne, Germany) were included in this study. Age ranged from 41 to 95 years, while body mass index (BMI) ranged from 17 to 47 kg.m-2. We found the ratio CtPo/Ct.Th to be predictive for non vertebral after sex, BMI and age adjustment (OR=2.62, AUC=0.83), comparable to femoral aBMD (OR=3.48, AUC=0.82). The fracture risk assessment by BDAT method in elderly, in a clinical setting, suggests the benefit of the affordable and transportable device for the routine use.
  • Miniatura
    Ítem
    In vivo pulse-echo measurement of apparent broadband attenuation and Q factor in cortical bone: a preliminary study
    (IPEM, 2021) Minonzio, Jean-Gabriel; Han, Chao; Cassereau, Didier; Grimal, Quentin
    Quantitative ultrasound (QUS) methods have been introduced to assess cortical bone health at the radius and tibia through the assessment of cortical thickness (Ct.Th), cortical porosity and bulk wave velocities. Ultrasonic attenuation is another QUS parameter which is not currently used. We assessed the feasibility of in vivo measurement of ultrasonic attenuation in cortical bone with a broadband transducer with 3.5 MHz center frequency. Echoes from the periosteal and endosteal interfaces were fitted with Gaussian pulses using sparse signal processing. Then, the slope of the broadband ultrasonic attenuation (Ct.nBUA) in cortical bone and quality factor ${Q}_{11}^{-1}$ were calculated with a parametric approach based on the center-frequency shift. Five human subjects were measured at the one-third distal radius with pulse-echo ultrasound, and reference data was obtained with high-resolution x-ray peripheral computed tomography (Ct.Th and cortical volumetric bone mineral density (Ct.vBMD)). Ct.Th was used in the calculation of Ct.nBUA while ${Q}_{11}^{-1}$ is obtained solely from ultrasound data. The values of Ct.nBUA (6.7 ± 2.2 dB MHz−1 .cm−1) and ${Q}_{11}^{-1}$ (8.6 ± 3.1%) were consistent with the literature data and were correlated to Ct.vBMD (${R}^{2}=0.92$, $p\lt 0.01$, RMSE = 0.56 dB.MHz−1.cm−1, and ${R}^{2}=0.93$, $p\lt 0.01$, RMSE = 0.76%). This preliminary study suggests that the attenuation of an ultrasound signal propagating in cortical bone can be measured in vivo at the one-third distal radius and that it provides an information on bone quality as attenuation values were correlated to Ct.vBMD. It remains to ascertain that Ct.nBUA and ${Q}_{11}^{-1}$ measured here exactly reflect the true (intrinsic) ultrasonic attenuation in cortical bone. Measurement of attenuation may be considered useful for assessing bone health combined with the measurement of Ct.Th, porosity and bulk wave velocities in multimodal cortical bone QUS methods.
  • Miniatura
    Ítem
    Real Time Waveguide Parameter Estimation Using Sparse Multimode Disperse Radon Transform
    (IEEE, 2021) Araya, Claudio; Martinez, Alejandro; Ramiandrisoam Donatien; Ta, Dean; Xu, Kailiang; Osses, Axel; Minonzio, Jean-Gabriel
    Osteoporosis and associated fragility fractures are still a societal problem. Several quantitative ultrasound approaches have been proposed to overcome limitations of the current gold standard DXA. Bi Directional Axial Transmission (BDAT) is based on the measurement of waves guided by the cortical bone shell. Cortical thickness (Ct.Th) and porosity (Ct.Po) estimates correspond to the maxima of the objective function Proj(Ct.Th,Ct.Po), initially defined as the projection of a tested model in the singular vector basis (method 1). Each model matrix has the same dimension, i.e., Nf=124 x Nk=256, 512, 1024 or 2048 pixels, of an ultrasonic guided wave spectrum experimental image Norm(f,k). The total number of models is equal to Nth,=38 x Npo=25, i.e., the number of cortical thickness and porosity taken into account, ranging respectively from 0.8 to 4.5 mm and 1 to 25%. Finally, each pixel of the alternative objective function (NthxNpo pixels) corresponds to the pixel-wise image multiplication between one model and the experimental guided wave spectrum image (method 2) or a sparse matrix multiplication between experimental and model reshaped vectors (method 3). The three methods were tested on data obtained on 400 measurements. It was observed that methods 2 and 3 provided the same Ct.Th Ct.Po values while differences with method 1 decreased with Nk. Acceptable differences, i.e., lower than the typical measurement resolution (0.2 mm for Ct.Th and 1% for Ct.Po) were achieved for Nk=2048. Using Matlab on a standard desktop, this calculation took 20, 4 and 0.3 s, for the methods 1 to 3, respectively. Method 3 calculation was achieved in 5 ms using C++. This last value opens perspective toward guiding interface improvement using real time objective function.
  • Miniatura
    Ítem
    Selection of Bone fragility-Related Features Obtained with Bi-Directional Axial Transmission, Through a Machine Leaming Strategy
    (IEEE, 2021) Miranda, Diego; Olivares, Rodrigo; Munoz, Roberto; Minonzio, Jean-Gabriel
    Osteoporosis is a widespread public health problem worldwide, characterized by low bone mass, which compromises strength and increases the risk of fracture. Currently, the gold standard for assessing fracture risk is measurement of areal bone mineral density with dual-energy X-ray absorptiometry (DXA). Several ultrasound techniques, such as Bi-Directional Axial Transmission (BDAT) have been presented as alternatives. For the first studies, classification between fractured and non fractured patients was based on classical ultrasonic parameters, such as velocities or cortical thickness and porosity, obtained from an inverse problem. Recently, novel parameters obtained from structural analysis guided wave spectrum images (GWSI) have been introduced. The aim of this study is to merge both points of view and explore which parameters are the most important to obtain a robust classification using a machine learning approach. This study uses the same set of patients used in previous studies with 195 patients associated with 8 ultrasonic parameters and 3 clinical factors (age BMI and cortisone intake). In addition, each patient corresponds to 10 GWSI, from which 32 parameters of structural analysis are extracted per image, leading to a total of 43 features per image. The dataset was divided into 70% of patients (n = 136) as training and 30% as testing (n = 59). The distribution of patients was adjusted for age and target class. The accuracy was calculated for an increased number of features, which ranking was obtained using Recursive Feature Elimination (RFE). The highest accuracy of 71% is obtained with the optimized parameters and a combination between 22 and 25 features. These result, comparable to femoral DXA (AUC = 0.71, adjusted linear regression), opens perspective towards robust detection of patients at risk of fracture with ultrasound.