Mapping anisotropy improves QCT-based finite element estimation of hip strength in pooled stance and side-fall load configurations
Hip fractures lead to mortality, morbidity and high health care costs. The effective prevention of hip fractures requires an accurate diagnosis of osteoporosis, which is currently based on measurement of areal bone mineral density (aBMD) measured by dual energy x-ray absorptiometry (DXA). However, the majority of fractures occur in patients with aBMD above the diagnostic threshold [1 –3]. This reflects the fact that aBMD alone has high specificity but low sensitivity. Alternatively, Kopperdahl et al. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - July 4, 2018 Category: Biomedical Engineering Authors: J. Panyasantisuk, E. Dall'Ara, M. Pretterklieber, D.H. Pahr, P.K. Zysset Source Type: research
Role of acoustic radiation force impulse imaging elastography in the assessment of steatohepatitis and fibrosis in rat models
Nonalcoholic fatty liver disease (NAFLD) is increasingly recognized as the hepatic manifestation of insulin resistance and the systemic complex known as metabolic syndrome. Currently, the prevalence of this condition is approximately 20% to 30% in the general population in affluent countries, and it has the potential to become a serious public health problem [1 –2]. Nonalcoholic steatohepatitis (NASH), the essential link between simple steatosis and cirrhosis in the NAFLD spectrum, could be present in one-third of NAFLD cases. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - July 3, 2018 Category: Biomedical Engineering Authors: Yanrong Guo, Haoming Lin, Changfeng Dong, Xinyu Zhang, Huiying Wen, Yuanyuan Shen, Tianfu Wang, Siping Chen, Yingxia Liu, Xin Chen Source Type: research
Warming the premature infant in the delivery room: Quantification of the risk of hyperthermia
Each year, over 15 million neonates are born prematurely – accounting for 10% of births worldwide. Most of neonatal mortality is linked to the prematurity. However, hypothermia in the delivery room is also an individualized factor of neonatal mortality and morbidity [1,2]. Preterm and low-birth-weight newborns are particularly at risk, since (i) their t hermoregulatory mechanisms are not efficient, and (ii) their body heat losses to the environment are greater than those of adults [3–5]. In the first few minutes after birth, the core body temperature (Tb) is no longer regulated by the intra-uterine environment, and so ...
Source: Medical Engineering and Physics - June 28, 2018 Category: Biomedical Engineering Authors: Armand Lahana, St éphane Delanaud, Romain Erbani, Anaïs Glusko-Charlet, Estelle Durand, Elodie Haraux, Laurent Ghyselen, Jean-Pierre Libert, Pierre Tourneux Tags: Technical note Source Type: research
In silico dynamic characterization of the femur: Physiological versus mechanical boundary conditions
It is established that bone tissue adapts and responds to mechanical loading. The characteristics of the mechanical loads, such as peak magnitude of ground reaction force, peak rate of force production, and repetition rate of these loads, are known to be important in regulating bone regeneration [1]. According to experimental studies, maximum bone formation directly depends on loading frequencies and targeted locations of bones [2 –6]. Zhao et al. [7] have demonstrated in an in vivo study performed on mice that the application of loads with frequencies near the natural frequency of bone favors bone formation. (Source: Me...
Source: Medical Engineering and Physics - June 23, 2018 Category: Biomedical Engineering Authors: E. Reina-Romo, J. Rodr íguez-Vallés, J.A. Sanz-Herrera Tags: Technical note Source Type: research
A novel stability-based EMG-assisted optimization method for the spine
In the absence of accurate non-invasive in vivo techniques, musculoskeletal models are widely employed to compute biomechanical loads on different body joints during static and dynamic activities [1,2]. Three approaches have been proposed to resolve joint kinetics redundancy. First, a pure optimization technique in which muscle forces are estimated by optimizing an assumed cost function such as the sum of squared or cubed muscle stresses [3]. Second, a pure electromyography (EMG)-assisted approach in which muscle forces are estimated from an assumed muscle EMG-force relationship during the task under consideration [4 –6]...
Source: Medical Engineering and Physics - June 23, 2018 Category: Biomedical Engineering Authors: S Samadi, N Arjmand Source Type: research
Development of an infant complete-airway in vitro model for evaluating aerosol deposition
In vitro airway models provide a convenient and scientifically useful testing platform for determining aerosol delivery to and deposition within the lungs [1 –4]. These models can be used to determine inhaled dose of airborne pollutants and bioaerosols arising from environmental exposures. Considering infants, a number of studies have implemented in vitro models to evaluate aerosol deposition in a portion of the airways. Widely used infant nasal models based on a single subject scan have been reported for pre-term [5] and 9-month-old [6] infants. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - June 22, 2018 Category: Biomedical Engineering Authors: Karl Bass, P. Worth Longest Source Type: research
Improved osseointegration with as-built electron beam melted textured implants and improved peri ‑implant bone volume with whole body vibration
In 2005, approximately 1 in 190 Americans were amputees. That ratio is expected to double by 2050 [1]. Transcutaneous osseointegrated implants hold the potential to overcome several shortcomings of traditional socket prostheses. An optimal fit is difficult to achieve with socket-type prostheses, often resulting in undesirable stresses on tissues most frequently resulting in painful lesions, bursae, inflammatory edema, soft-tissue calcification or neuromas [2,3]. Socket prosthetic devices also lack stability due to their inefficient connection to the body. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - June 11, 2018 Category: Biomedical Engineering Authors: David S. Ruppert, Ola L.A. Harrysson, Denis J. Marcellin-Little, Laurence E. Dahners, Paul S. Weinhold Source Type: research
Kinematics-based prediction of trunk muscle activity in response to multi-directional perturbations during sitting
When balance of a seated person is challenged, postural stability is restored via activation of the major trunk muscles. Insights regarding the timing, amplitude, and time course of such muscular activation are thought to be important in various domains, including basic movement science, ergonomics, prevention, rehabilitation, and assistive technology development. In spite of this importance, the muscular response to seated perturbations and its characteristics are not fully understood or described. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - June 9, 2018 Category: Biomedical Engineering Authors: Jacques Bobet, Kei Masani, Milos R. Popovic, Albert H. Vette Source Type: research
Positioning accuracy of a patient-tailored rimmed wedge implant for corrective osteotomy of the distal radius
Malunion after a distal radius fracture is very common and if symptomatic, is treated with corrective osteotomy surgery [1]. In traditional corrective distal radius osteotomy surgery, the radius is cut at the fracture location and a bony wedge is either inserted or removed to improve positioning of the distal radius. It further improves the anatomical relationship with the ulna and the carpal bones. Positioning is usually followed by fixation of the bone segments using a plate and screws. It has been shown however, that conventional surgical planning [2], which is based on 2-D X-ray images, leads to suboptimal positioning ...
Source: Medical Engineering and Physics - May 22, 2018 Category: Biomedical Engineering Authors: Johannes G.G. Dobbe, Giuliana Caiti, Albert W. Schreurs, Simon D. Strackee, Maikel Beerens, Geert J. Streekstra Source Type: research
How can a short stem hip implant preserve the natural, pre-surgery force flow? A finite element analysis on a collar cortex compression concept (CO4)
The structure of bone follows from adaptation to predominant loading conditions. Total hip arthroplasty (THA) replaces femur parts by an implant and changes the load transfer by the implant-bone interface and thereby largely determines the consecutive force flow through the femur. As a consequence, the post-surgery force flow through bone induces stimuli for remodeling; bone resorption along with stiffness loss takes place in regions of lower loading, an increase of bone density and stiffness is induced in regions of higher loading. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - May 14, 2018 Category: Biomedical Engineering Authors: B. Eidel, A. Gote, A. Ohrndorf, H.-J. Christ Source Type: research
Identifying the myogenic and metabolic components of cerebral autoregulation
fraction (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - May 14, 2018 Category: Biomedical Engineering Authors: S.J. Payne Source Type: research
Can the contralateral limb be used as a control during the growing period in a rodent model?
Bilateral symmetry of long bones is used by the researchers in musculoskeletal research and clinical practice. It is a commonly hypothesized concept used in geometric, biological and clinical studies. It is deemed as a reflection symmetry in which similar anatomical parts are arranged on opposite sides of a median axis so that only one plane of symmetry can divide the individual into substantially identical halves [1]. Usually, symmetries are perceived as extrinsic geometric and volumetric properties of shapes [2], implying that with a different orientation, the geometric shape of a structure is similar to another structur...
Source: Medical Engineering and Physics - May 12, 2018 Category: Biomedical Engineering Authors: Tanvir Mustafy, Ir ène Londono, Isabelle Villemure Source Type: research
Assessment of structural and hemodynamic performance of vascular stents modelled as periodic lattices
Coronary heart disease is the most common type of heart disease and the leading cause of death in the developed world [1]. It is mainly caused by the development of an atherosclerotic lesion in an artery. The lesion results in plaque build-up along the inner walls of the artery and eventually leads to an occlusion, restricting blood flow. A common treatment is angioplasty, which involves inserting percutaneously a balloon at the end of a catheter into the site of the occlusion. The balloon is then inflated to increase the size of the lumen to restore blood flow. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - May 12, 2018 Category: Biomedical Engineering Authors: Purnendu K.M. Prithipaul, Michael Kokkolaras, Damiano Pasini Source Type: research
A simplified method to account for wall motion in patient-specific blood flow simulations of aortic dissection: Comparison with fluid-structure interaction
Aortic Dissection (AD) is a life-threatening vascular condition initiated by a tear in the intima layer that allows the blood to flow within the aortic wall and leads to the formation of two distinct flow channels, the true lumen (TL) and the false lumen (FL), separated by the so-called intimal flap (IF) [1]. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - May 11, 2018 Category: Biomedical Engineering Authors: Mirko Bonfanti, Stavroula Balabani, Mona Alimohammadi, Obiekezie Agu, Shervanthi Homer-Vanniasinkam, Vanessa D íaz-Zuccarini Tags: Technical note Source Type: research
Measuring relative positions and orientations of the tibia with respect to the femur using one-channel 3D-tracked A-mode ultrasound tracking system: A cadaveric study
Detailed knowledge of the skeletal knee kinematics is very important to assess pathologies of the lower limb [1 –3]. Accurately measured tibiofemoral kinematics is also useful for evaluation of surgical techniques such as implantation of artificial knee implants [4,5] and for the development and validation of computer models (e.g. musculoskeletal models) capable of simulating normal and pathological human m ovement [6,7]. (Source: Medical Engineering and Physics)
Source: Medical Engineering and Physics - May 11, 2018 Category: Biomedical Engineering Authors: Kenan Niu, Jasper Homminga, Victor Sluiter, Andr é Sprengers, Nico Verdonschot Tags: Technical note Source Type: research
