al fluid dynamics is highly related to specifics of geometry and flow wave form and approximations necessary in a study such as this, and for example imaging accuracy and conversion to a numerical grid can greatly affect accuracy in the final computational fluid dynamics results. The authors are aware of these problems hence the decision to look at stenosis in a steady state flow and the inherent problems associated with it. Global flow patterns and also the detailed distribution of hemodynamic parameters were found to be grossly distorted by the changes in vessel geometry brought about by the disease process. Downstream of a stenosis, pressure recovery and the wall curvature associated with the increase in cross-sectional area gives rise to flow separation. All these were considered in the development of software, using the developed equations and visual basic application tools.
The developed software can be installed from a Compact Disc (CD). Once you insert the CD into your computer, it will take you through the installation and will deposit a shortcut icon on the desktop. Once you click on the icon, Figure 1 will appear, it is the home page which shows the Siriraj scoring interface. It allows the input of physical and measured information data from a patient. Information like the level of consciousness (stupor or drowsy), vomiting or not, headache within the last two
hours, blood pressure and atheroma markers like diabetes, angina and intermittent claudication will compute a score to differentiate whether the patient is suffering from ischaemia or haemorrhage. If the computed value is less than one as shown in Figure 2, then the patient is suffering from Ischemia and if it is more than one as shown in Figure 3, then the patient is suggested to be suffering from haemorrhage. If the value falls between –1 and 1, then the condition is undefined as shown in Figure 4,
Figure 2. Diagnosed score for haemorrhagic.
Figure 3. Diagnosed score for ischaemic.
Figure 4. Diagnosed score for unidentified situation.
Figure 6. A diseased artery with stenosis at both sides of the vessel.
hence scanning is necessary, before medication. Figure 5 shows the stenosis simulation interface for every patient that is diagnosed for ischemia or haemorrhage, the information and the profile of the patient is simulated and stored against the parameters for a possible reference for later diagnosis. Figure 6 shows a profile of a patient with stenosis at both sides of the artery. From the shape of the profile the physician can now give medication.
In conclusion, software was developed using one-dimensional non-linear equations of blood flow which was solved using the Riemann based methods constructed within the finite volume framework. Interfaces were developed to read in some measured parameters and information form a subject and the program analyses the information and gives a feed back on the situation of the subject to the medical personal, which in turn takes decision on treatment. The software package can assist clinicians in early screening of patients at risk and physician can rely on the result to start thrombolytic and/or anticoagulation therapy.
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