These results reveal a strong, spatially localized correlation between diminished WSS and differential expression of biological markers of vascular remodeling in elastase-induced saccular aneurysms. The ability of the wall to function and maintain a healthy endothelium in a low shear environment appears to be significantly impaired by chronic exposure to low WSS.

Regional differences in hemodynamic loads on arterial walls have been associated with localized vascular disease such as atherosclerosis and cerebral aneurysms. Due to their intrinsic geometric relevance, three-dimensional (3D) reconstructions of arterial segments are frequently used in hemodynamic studies of these diseases. However, it is not possible to use them to systematically vary geometric features for parametric studies. Idealized vascular models are inherently suited for parametric studies, but are limited by their tendency to oversimplify the vessel geometry. In this work, a hierarchy of three parametric bifurcation models is introduced. The models are relatively simple, yet capture all geometric features identified as common to cerebral bifurcations in the complex transition from parent to daughter branches. While these models were initially designed for parametric studies, we also evaluate the possibility of using them for 3D reconstruction of cerebral arteries, with the future goal of improving reconstruction of poor quality clinical data. The lumen surface and vessel hemodynamics are compared between two reconstructed cerebral bifurcations and matched parametric models. Good agreement is found. The average and maximum geometric differences are less than 3.1 and 10%, respectively for all three parametric models. The maximum difference in wall shear stress is less than 8% for the most complex parametric model.

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In clinical practice, Myocardial Blush Grade (MBG) has been used to obtain information about microvascular condition in myocardial infarction by using coronary angiogram. Quantitative Blush Evaluator (QuBE) program was developed for the calculation of myocardial perfusion score. Calculation of QuBE values is often affected by patient motion and become inaccurate. In this paper, we proposed an algorithm to reduce undesired motion in coronary angiogram. This algorithm correct frame motion by shifting each single frame according to the best correlation with the first frame. The effectiveness of this stablizing method achieved by searching scale-invariant feature from each frame of coronary angiogram in order to find the best correlation between two frame. The results showed that MBG categorization based on modified QuBE program exactly match with the original QuBE program. In addition, results also showed that application of stabilization algorithm using SIFT method decreased the deviation by 15% therefore it increased the accuracy of QuBE value calculation. Finally, this new algorithm also decreased the execution time by 71% so the doctor could faster patient diagnosis. In conclusion the new algorithm could enhance the qualitiy of QuBE value calculations in MBG scoring for coronary angiogram. Keyword: coronary angiography, myocardial blush grade, stabilization, scale-invariant feature transform, quantitative blush evaluator.

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