Mohd Azrul Hisham Mohd Adib

Prediction on Behaviour of Blood Velocity and Mitral Leaflet Displacement in the Different Shapes of Heart Valve during Cardiac Cycle

The number of cases for heart diseases is increasing every day, even though medication technologies are always improving and moving forward. In this paper, the objectives of the study are to investigate the effect of blood flow velocity and leaflet displacement using different shapes of simplified two dimensional heart valve leaflets in the diastole condition. Four different shapes of heart valve were created and the simulation was performed by using Fluid Structure Interaction (FSI). From the results obtained, the triangle shaped leaflet showed it had the highest blood velocity changes and leaflets displacement changes in a one second period when compared to the other three shapes. The outcome simulation result shows that a large vortex formed behind the leaflet and leaflet deformed when the blood flow into left ventricle is agreed with the results in literature. In conclusion, four different shapes of two dimensional model of mitral valve has been developed and investigated for applying the most suitable shape in future artificial valve design.

Degenerative vs Rigidity on Mitral Valve Leaflet Using Fluid Structure Interaction (FSI) Model

The objectives of this study are to observe the deformation of mitral leaflet in systole condition and compare the rigidity of heart valve leaflet during systole and diastole conditions. Two-dimensional model of the mitral valve leaflet with ventricle were created using fluid structure interaction model in computational simulations. The result shows rigidity of heart valve leaflet always opposite to degeneration and the simulated displacement models corresponded to normal deformation in physical heart valve in systole condition. Modeling simulation techniques are very useful in the study of degenerative heart valve and the findings would allow us to optimize feature and geometries to reduced deformation of heart valve failure.

Study the Heart Valve Elasticity and Optimal of Vortex Formation for Blood Circulation Measurement on the Left Ventricle Using the Heart Simulator (Heart-S) Apparatus

Modeling of heart simulator gives a better understanding of blood circulation and the figure of the heart valves movement as well as the fluid flow movement in the heart chamber. In this study, the relationship between heart valve elasticity and the angle of the heart valve position to the heart valve opening width were investigated. Also, the optimal of vortex formation was observed by using the heart simulator (Heart-S) apparatus on the left ventricle during the cardiac cycle. The result shows good relation on heart valve elasticity and the angle of the heart valve position to the valve opening. The optimal of vortex formation in the heart chamber also clearly observed.

Effect on the Reconstruction of Blood Vessel Geometry to the Thresholds Image Intensity Level for Patient Aneurysm

Thresholding is the greenest and most generally used techniques in image segmentation. This threshold determination can be used to extract various features of the vascular geometry that is used for understanding and analyzing of the image. Our objective is to investigate the influence of the modernization of blood vessel geometry to the threshold image intensity level difference in vessel segmentation. This study included a patient with cerebral aneurysms. We employed three different threshold levels from 200, 400 and 600 in order to determine the influence of the threshold objectively. The flow solution variation on exemplified by wall shear stress (WSS) presents similarity due to the location and magnitude of geometry variation resulting from the different threshold image intensity level and relatively small changes can lead to important dissimilarity in geometry of vessel and flow feature, predominantly in location with an enormous variety of cross sectional area. This is the significance of the understanding of modeling computational simulations of blood flow and can be expressively effected by alterations in geometry different.

Analysis on Rigidity of Mitral Valve Leaflet (MVL) and Backflow Problems during Cardiac Cycle

Problems that occur in the mitral valve are now worrying an increasing number of patients each day. In the mitral valve, regional variations in structure and material properties combine to affect the biomechanics of the entire valve. Previous studies have shown that the mitral valve leaflet tissue is highly extensible. The objective of this study was to investigate the relationship between the rigidity of mitral valves leaflet and backflow problems. Two stages of mitral valves analysis systolic and diastolic condition and also with and without ventricle were investigated. 2D models of the mitral valve leaflet (MVL) were created in ADINA-FSI for computational fluid dynamic analysis. The results show a linear relationship between rigidity of the mitral valves leaflet and volume of backflow. In conclusion, these computational techniques are very useful in the study of both mitral valve leaflet disease and failure of prostheses.

Development of 3D printed heart model for medical training

Three-Dimensional (3D) printing is emerging as an enabling technology for a wide range of new applications. This study focuses on the medical application of 3D printer using basic fundamental 3D printing mechanisms. The objective of this study is to develop a heart model with specific requirements for medical training using Flyingbear P902 3D printer and Flex Thermoplastic Polyurethane (TPU) filaments as the depositing materials. The study involved two trials with the same operation procedure and 3D printer specifications. The first trial utilized non-transparent TPU filament and the second trial utilized transparent TPU filament. The application of this technology in developing a heart model was evaluated based on the requirements fulfilled by both printed heart models in both trials. The problems (such as inflexibility and less transparency), limitations and proposed solutions are discussed. The emergence of cardiovascular diseases such as congenital heart disease, coronary artery disease, surgical and catheter-based structural disease make 3D printing a new tool to design, plan and carry out challenging cardiovascular interventions.

Ergonomic Study on Wrist Rehabilitation Therapy (WRist-T) Device

The emerging issue in complex joints such as human wrist is usually the disability to be precisely coordinated with a traditional mechanical joint. In such cases, mechanical differences between human and robotic joints could lead to musculoskeletal disorder (MSD) and overconstraint due to the device over rotation, misalignment of the rotation axis and also the design of the device. This paper focuses on ergonomic comparison studies between the previous and present WRist-T devices. The result of the ergonomic study especially on anthropometry and ergonomic evaluation shows that the present model is better than the previous one.

Development of Heart Simulator (Heart-S) on the Left Ventricle for Measuring the Blood Circulation during Cardiac Cycle

Heart is a complex structure which acts as a blood pump in mammal’s body. It is important to have detail study for the heart structure. Modeling of heart structure gives a better understanding and figure of the heart valve’s movement as well as the fluid flow movement in the heart chamber. In this paper, the heart simulator (Heart-S) on the left ventricle for measuring the blood circulation during cardiac cycle was proposed. Throughout the experimental modeling of heart valve structure by using rhythmic fluid flow in a closed chamber, the relationship between heart valve elasticity and heart valve angle position to the valve opening width were investigated. The main aspect of the present development is to provide a heart simulator apparatus to obtain data for development of artificial heart and for observing the blood circulation measurement. The result shows good agreement on valve elasticity and the velocity of the fluid from the vortex in the heart chamber can be found after the experiment. The novelty of this development is contributing to the study of the optimal vortex formation in the heart chamber and observe the blood circulation measurement.

Measurement of Threshold Image Intensities on Difference of Vascular Model: Effect on Computational Fluid Dynamics for Patient-Specific Cerebral Aneurysm

Threshold image intensity for patient vascular models is determined instinctively. In this study, we used the simple method of threshold resolve to evaluate the effect of threshold image intensity level on computational fluid dynamics (CFD) of patient-specific cerebral aneurysm. This investigation involved five patients with internal carotid aneurysms collected in retrospect between August 2010 and October 2012. In 3-dimensional rotational angiography with digital subtraction angiography (DSA) image data, we set five straight line probe across the parent of the internal carotid artery and deliberate the average profile curve of the image intensity along this line. To determine the threshold image intensity level objectively, we calculated the threshold coefficient Cthre using this profile curve. The effect of Cthre value on vascular model configuration and the wall shear stress (WSS) distribution of the aneurysm was evaluated. Result shows for the inlet area and volume of the vascular model decreased and WSS increased according to the Cthre value increase. In one stage, the pattern of WSS distribution changed strangely and the threshold image intensity level can result reflective effects on CFD. This finding necessary to advance a further understanding of problems in image segmentation and solving the patient-specific aneurysm problems.

Review: Modelling of meniscus of knee joint during soccer kicking

Knee is a part of the body that located between thigh and shank is one of the most complicated and largest joints in the human body. The common injuries that occur are ligaments, meniscus or bone fracture. During soccer games, the knee is the most critical part that will easily injure due to the shock from an external impact. Torn meniscus is one of the effects. This study will investigate the effect towards the meniscus within the knee joint during soccer ball kicking. We conduct a literary review of 14 journals that discuss the general view of meniscus and also soccer kicking. The selected topics for this review paper are meniscal function, meniscal movement, meniscal tears and also instep kick. As a finding, statistics show that most meniscal tears (73%) occurred in athletes who were soccer players, basketball players or skiers. The tear is frequently happening at the medial side rather than lateral side with a percentage of 70%.