- OPEN ACCESS RESEARCH ARTICLE
- A Study on the Finite Element Model for Head Injury in Facial Collision Accident
- Molecular & Cellular Biomechanics, Vol.17, No.1, pp. 49-62, 2020, DOI:10.32604/mcb.2019.07534
- Abstract In order to predict and evaluate injury mechanism and biomechanical response of the facial impact on head injury in a crash accident. With the combined modern medical imaging technologies, namely computed tomography (CT) and magnetic resonance imaging (MRI), both geometric and finite element (FE) models for human head-neck with detailed cranio-facial structure were developed. The cadaveric head impact tests were conducted to validate the headneck finite element model. The intracranial pressure, skull dynamic response and skull-brain relative displacement of the whole head-neck model were compared with experimental data. Nine typical cases of facial traffic accidents were simulated, with the individual stress wave propagation paths to the intracranial contents through the facial and cranial skeleton being discussed thoroughly. Intracranial pressure, von Mises stress and shear stress distribution were achieved. It is proved that facial structure dissipates a large amount of impact energy to protect the brain in its most natural way. The propagation path and distribution of stress wave in the skull and brain determine the mechanism of brain impact injury, which provides a theoretic basis for the diagnosis, treatment and protection of craniocerebral injury caused by facial impact.
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- A Retrospective Respiratory Gating System Based on Epipolar Consistency Conditions
- Molecular & Cellular Biomechanics, Vol.17, No.1, pp. 41-48, 2020, DOI:10.32604/mcb.2019.07383
- Abstract Motion artifacts of in vivo imaging, due to rapid respiration rate and respiration displacements of the mice while free-breathing, is a major challenge in micro computed tomography(micro-CT). The respiratory gating is often served for either projective images acquisition or per projection qualification, so as to eliminate the artifacts brought by in vivo motion. In this paper, we propose a novel respiratory gating method, which firstly divides one rotation cycle into a number of segments, and extracts the respiratory signal from the projective image series of current segment by the value of the epipolar consistency conditions (ECC), then in terms of the measured average respiratory period, sets next segment’s start-up time and rotation speed of the gantry for respiratory phase synchronization, and so on so forth. The gating procedure is through the whole projections of three cycles, only one among three projections at each angle is qualified by their phase value and is retained for future use for tomographic image reconstruction. In practical experiment, the ECC based gating method and the conventional hardware gating method are employed on micro CT imaging of C57BL/6 mice respectively. The result shows that, compared with the hardware based one, the proposed method not only achieve much better consistency in the projection images, but also suppresses the streak artifacts more effectively on the different parts like the breast, abdomen and head of in vivo mice.
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- Multifrequency Microwave Imaging for Brain Stroke Detection
- Molecular & Cellular Biomechanics, Vol.17, No.1, pp. 33-40, 2020, DOI:10.32604/mcb.2019.07165
- Abstract CT and MRI are often used in the diagnosis and monitoring of stroke. However, they are expensive, time-consuming, produce ionizing radiation (CT), and not suitable for continuous monitoring stroke. Microwave imaging (MI) has been extensively investigated for identifying several types of human organs, including breast, brain, lung, liver, and gastric. The authors recently developed a holographic microwave imaging (HMI) algorithm for biological object detection. However, this method has difficulty in providing accurate information on embedded small inclusions. This paper describes the feasibility of the use of a multifrequency HMI algorithm for brain stroke detection. A numerical system, including HMI data collection model and a realistic head model, was developed to demonstrate the proposed method for imaging of brain tissues. Various experiments were carried out to evaluate the performance of the proposed method. Results of experiments carried out using multifrequency HMI have been compared with the results obtained from single frequency HMI. Results showed that multifrequency HMI could detect strokes and provide more accurate results of size and location than the single frequency HMI algorithm.
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- On the Onset of Cracks in Arteries1
- Molecular & Cellular Biomechanics, Vol.17, No.1, pp. 1-17, 2020, DOI:10.32604/mcb.2019.07606
- Abstract We present a theoretical approach to study the onset of failure localization into cracks in arterial wall. The arterial wall is a soft composite comprising hydrated ground matrix of proteoglycans reinforced by spatially dispersed elastin and collagen fibers. As any material, the arterial tissue cannot accumulate and dissipate strain energy beyond a critical value. This critical value is enforced in the constitutive theory via energy limiters. The limiters automatically bound reachable stresses and allow examining the mathematical condition of strong ellipticity. Loss of the strong ellipticity physically means inability of material to propagate superimposed waves. The waves cannot propagate because material failure localizes into cracks perpendicular to a possible wave direction. Thus, not only the onset of a crack can be analyzed but also its direction. We use the recently developed constitutive theories of the arterial wall including 8 and 16 structure tensors to account for the fiber dispersion. We enhance these theories with energy limiters. We examine the loss of strong ellipticity in uniaxial tension and pure shear in circumferential and axial directions of the arterial wall. We find that the vanishing longitudinal wave speed predicts the appearance of cracks in the direction perpendicular to tension. We also find that the vanishing transverse wave speed predicts the appearance of cracks in the the direction inclined (non-perpendicular) to tension. The latter result is counter-intuitive yet it is supported by recent experimental observations.
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- New Concept in Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA)
- Molecular & Cellular Biomechanics, Vol.17, No.1, pp. 25-31, 2020, DOI:10.32604/mcb.2019.07310
- Abstract The world-wide impact of traumatic injury and associated hemorrhage on human health and well-being is significant. Methods to manage bleeding from sites within the torso, referred to as non-compressible torso hemorrhage (NCTH), remain largely limited to the use of conventional operative techniques. The overall mortality rate of patients with NCTH is approximately 50%. Studies from the wars in Afghanistan and Iraq have suggested that up to 80% of potentially survivable patients die as a result of uncontrolled exsanguinating hemorrhage. The commercially available resuscitative endovascular balloon occlusion of the aorta (REBOA) is a percutaneous device for the rapid control of torso hemorrhage in trauma. A compliant balloon is inserted via the femoral artery and inflated in the thoracic or abdominal aorta, providing inflow control of the abdomen, pelvis, or groin/lower extremities. Recent studies indicate that REBOA carries an inherent risk of aortic injury due to over-inflation and possible risk of aortic or iliac artery rupture. A new approach isto resolve the issue of balloon sizing and over-inflation. We propose a novel concept to be used in trauma facility for arterial occlusion to eliminate arterial injury and the risk of vascular rupture through real time balloon diameter profile measurements to ensure proper inflation. The proposed concept, called Smart Resuscitative Endovascular Balloon Occlusion (SREBO) will be novel in the following aspects: 1) It will have electrical conductance-based navigation technology to target the desired site of balloon deployment in the aorta, 2) The balloon can determine the time of proper inflation using electrical conductance catheter technology. This technology would eliminate the risk of arterial rupture and simplify the procedure in the trauma facility or medical clinics without significant training. The results can be displayed on a handheld device. This novel device has the potential to save civilians in trauma or soldiers injured on the battlefield.
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- Kinematic and Dynamic Characteristics of Pulsating Flow in 180o Tube
- Molecular & Cellular Biomechanics, Vol.17, No.1, pp. 19-24, 2020, DOI:10.32604/mcb.2019.07817
- Abstract Kinematic and dynamic characteristics of pulsating flow in a model of human aortic arch are obtained by a computational analysis. Three-dimensional flow processes are summarized by pressure distributions on the symmetric plane together with velocity and pressure contours on a few cross sections for systolic acceleration and deceleration. Without considering the effects of aortic tapering and the carotid arteries, the development of tubular boundary layer with centrifugal forces and pulsation are also analyzed for flow separation and backflow during systolic deceleration.
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