Respect for Tissue Representation Using Photoelastic Stress Analysis for Endovascular Surgery Simulation - Microsurgery: Advances, Simulations, and Applications - page 147

three-dimensional visualization of stress. Figure 4.23 shows three-
dimensional views of the blood vessel model when its inner pressure
was 120 mmHg and also shows views of the model with a guide wire
applying stress to the wall and with inner pressure of 80 mmHg.

Stress measurement error of images B' 400,5 80 , B' 400,5 120 and B' 400,5 160
is 10.73%, 4.55% and 3.18%, respectively [8].

[mmHg]

B' 400,5 80 B' 400,5 80GW

Stress 1120

[mmHg]

754 840

562

560

375

280

187

1 m m

0

b)

Guide Wire

1 mm

1mm 1mm

0

B' 400,5 120 B' 400,5 160 Stress

[mmHg]

0.8mm Guide Wire

0.8mm Guide Wire

[mmHg] 750

1120

562

740

375

560
280

187

1 m m

0

c)

a)

1m m 0

Figure 4.23 (a) Reconstruction stress distribution slices using ML-EM
method in a model of vasculature slice at pressures of 80, 120
and 160 mmHg, and with guide wire inserted at 80 mmHg.
(b) Three-dimensional visualization of stress and longitudinal
stress variation within the model wall for a phantom with inner
pressure of 120 mmHg. (c) Three-dimensional visualization
of stress and longitudinal stress variation within the model
wall for a phantom with a guide wire inserted and with inner
pressure of 80 mmHg. See also Color Insert.

Slices of stress produced by a guide wire and inner pressure on
a blood vessel model were reconstructed and three-dimensionally
visualized; however, for this experimental setup and measurement
accuracy, the lumen cross-sectional diameter of the model is limited
to 11.8 mm. Image sizes of the reconstruction method are limited

to powers of 2; for this case images of 128 × 128 pixels were used.
The model lumen limit and measurement accuracy depend on the
camera resolution and the size of the blood vessel model on the
screen. The complete cross section of the model must appear into
the sinogram to be reconstructed properly, and it is desirable to
maximize the number of pixels belonging to the model wall. The
membrane thickness must be at least three pixels to achieve the
accuracy shown in this chapter. However, increasing resolution
implies increasing the time required to reconstruct each slice and
produce the three-dimensional visualization.