ABSTRACT
Objective To demonstrate the relationship between modified Hausdorff distance (MH) and the spatial change of arterial vasculature in residuum. Methods Data of the vascular model were obtained from CT scans of clinical cases, and a centerline model of the residuum vasculature was established by setting the appropriate parameter of distance between control points (DCP) in MIMICS 10.0. Deformation was applied on the model through compiling the program in MATLAB. The MH values before and after the deformation were calculated and analyzed. According to different locations of the rotation axis, the deformation was divided into four cases (C1, C2, C3, C4) on the basis of growth order in node numbers and total length of the vasculature. Results MH increased with the increment of the vascular rotation angle, but due to different maximum rotation radius and total length of the vascular vessel, 4 deformed models showed different growth trends. With the rotation angle increasing, MH gradually increased from C1 to C4. The maximum change occurred from C2 to C3, and minimal change occurred from C3 to C4. Specifically, the maximum rotation radius and total length of the vessels from C1 to C2 increased by 22.2% and 91.3%, while those from C3 to C4 increased by 14.1% and 26.8%, respectively. Moreover, the maximum change of MH value was 60.4% from C1 to C2 and 4.5% from C3 to C4. Conclusions MH can be an effective parameter to indicate spatial change of the residuum vasculature. MH of the residuum vasculature is proportional to deformation angle of the vessel, and the maximum rotation angle has a significant influence on MH. Moreover, when DCP is smaller than 3 mm, the influence of parameter setting can be avoided effectively. In addition, MH can also be applied in the studies of vasculature change and comparison.
ABSTRACT
Objective To investigate the influence of the location of drug release and the stent spacing on drug deposition in curved artery walls. Method 2D curved artery and strut models were employed to carry out a numerical investigation on drug deposition under different drug release surfaces or stent spacing ( 1 strut length, 3 strut lengths, 7 strut lengths ). The results were compared with those in a straight artery. Results The drug depositions produced by four different surfaces of a single strut were quite different. Compared with the curved artery, the superiority of drug release from the top surface of the straight artery was reduced, while the weakness of drug release from proximal surface was substantially increased. There was no significant change for drug release from the distal surface. The average drug concentration increased with interstrut spacing increasing, but the percentage increase was less than that in the straight artery. Concentration differences were observed between the inside and outside of the curved artery, which on the outside showed much lower. Conclusions The local flow alteration, the drug release location and the stent spacing have significant effects on drug deposition in a curved artery and the result is obviously different from that in a straight artery.