Biomedical Engineering Reference
In-Depth Information
Table 12.1:
Effect of changes in material properties and material model on
predicted fiber stretch. “Forward” indicates the forward FE solution, the “gold
standard”. Columns indicate locations 1-8 of the left ventricle, defined in the
caption for Fig. 3.13 above
1
2
3
4
5
6
7
8
Location
Upper ventricle
Mid-ventricle
Forward
1.09
1.06
1.12
1.07
1.08
1.04
1.02
1.05
µ
+
24%
1.09
1.09
1.13
1.07
1.07
1.03
1.03
1.05
µ
−
24%
1.09
1.09
1.13
1.07
1.08
1.03
1.03
1.05
C
3
+
24%
1.09
1.08
1.13
1.08
1.08
1.03
1.03
1.05
C
3
−
24%
1.10
1.09
1.13
1.07
1.08
1.03
1.03
1.05
Neo-Hookean
1.10
1.07
1.13
1.07
1.07
1.02
1.02
1.05
12.3.4.2
Myocardial Infarction
To study changes in systolic wall function due to myocardial infarction, a warp-
ing analysis was performed on a 3-D cine-MRI image data set for an individ-
ual with a lateral wall myocardial infarction (Male, 155 lbs, 51 y/o at time
of scan, diabetic w/small infarction.) The subendocardial infarction can be
seen as the hyperenhancement of the lateral wall shown in the ce-MRI image
(Fig. 3.15A).
Delayed contrast enhanced MRI (ce-MRI) has been shown to be able to iden-
tify regions of infraction in the myocardium as hyperenhanced [93-96]. Further-
more, studies have indicated that the transmural extent of the hyperenhance-
ment of ce-MRI predicts recovery of function after revascularization [97, 98] and
can predict improved contractility post-revascularization [94].
To acquire the ce-MRI image data sets, the patients were placed supine in
a 1.5T clinical scanner (General Electric) and a phased-array receiver coil was
placed on the chest for imaging. A commercially available gadolinium-based
contrast agent was administered intravenously at a dose of 0.2 mmol/kg and
gated images were acquired 10-15 min after injection with 10 s breath holds.
The contrast-enhanced images were acquired with the use of a commercially
available segmented inversion-recovery sequence from General Electric. The
3-D cine-MRI image data sets for this patient were acquired on a 1.5T GE scan-
ner (256
×
256 image matrix, 378 mm FOV, 10 mm slice thickness, 10 slices).
The volumetric MRI dataset corresponding to end-systole was designated as
the
template
image (Fig. 12.15C) while the image dataset corresponding to
