ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

initialization. Using built-in and custom-written function facilities provided by the
software, the quantities given in Table 1 were calculated:
1. Variation of Instantaneous Maximum
Velocity within the aneurysm sac
2. Maximum of Instantaneous Maximum
Velocity by time within the aneurysm sac
3. Average of Instantaneous Maximum
Velocity by time within the aneurysm sac
4. Variation of Instantaneous Average
Velocity within the aneurysm sac
5. Maximum of Instantaneous Maximum
Velocity by time within the aneurysm
6. Average of Instantaneous Maximum
Velocity by time within the aneurysm
u~
max
t
t , 2
u
,
t , max u x
uˆ max max x t 2
1 T
umax
tdt
T max u x,
,
0
2 t
t dV
u~ u x,
2
aver t
dV
ˆ max u~
t
ux,
t
2
dV
uaver aver
u
1
T
T
aver 0
dV
dt
Table 1 – Proposed Comparative Measures for Stent Efficiency
Vanev dV
The aneurysm volume is defined as
and T is one cardiac cycle period (1
sec), u is the velocity vector, x is the spatial coordinates in 3D and
..
2 is L2 norm.
3. RESULTS AND DISCUSSION
The results of other average data are developed following formulation in Table 1 and
percent of those parameters against deployment, as well as aneurysm volumes (i.e.,
1-stented/unstented) are given in Table 2. Also, a sample view of how flow field
changes for patient 4 is given in Figure 3.
u max û max u aver û aver V anev Medical Outcome
Minimal region of flow
remaining after 1 year.
Immediate clotting of
Patient 1 6.3% 0.4% 41.1% 49.9% 222.03
Patient 2 -6.7% -11.1% 43.6% 41.9% 3859.45
Patient 3 7.9% 3.6% 45.5% 38.8% 93.44
whole anurysm
Complete clotting after 6
months
Patient 4 15.0% 10.2% 70.3% 68.0% 3951.85 Hemorrage – 1 week later
Table 2 - Change of Stent Efficiency Measures
An outcome is that, stent deployment has increased the oscillation over mean for all
quantities, except for patient 1. It is also seen that, the greater the aneurysm, the greater
the peak velocity compared to global motion in the aneurysm; a parameter which is
greatly influenced by the application of a stent.
Clotting of blood is dependent to flow, as well as chemical parameters [8]. Poor
aneurysm treatment is fatal, and this risk is always present. Thus, it has been presumed
and seen in previous studies (as in [8,9]) that the clotting within aneurysm should be a
function of flow parameters within the aneurysm sac [9]. Though this study is limited to