Patient-Specific Vascular Modeling - Microsurgery: Advances, Simulations, and Applications - page 85

3.5 Patient-Specific Vascular Modeling

In this section, three-dimensional data of the blood vessel
reconstructed from the individual information is applied to the
fabrication method of a solid vascular model. A silicone model
that reproduces individual cerebral vascular lumen inside its cubic
structure is fabricated by using the CT and MRI information. The
fabrication method of the model considering the previously stated
requirements is as follows:
1. Reconstruction of 3D vascular coniguration from CT/MRI
information
2. Fabrication of vascular master mold by rapid prototyping
(RP)
3. Injection molding using silicone elastomer
4. Lost wax reproduction of vascular lumen
In this modeling, we irst reconstructed the three-dimensional
coniguration of cerebral artery using 100 digital slice images
obtained with multi-slice CT scanning with regular 0.5 mm intervals
and 0.3 mm/pixel resolution. Figure 3.7a shows one of the slice
image used for the reconstruction. We took in each slice image,
as two-dimensional scalar ield comprising CT value, into three-
dimensional space virtually created in computer according to the
interval of 0.5 mm, and heaped up into three-dimensional scalar
ield. Then, by extracting areas that had identical CT value, which
corresponds to the boundary region of artery, we extracted three-
dimensional outline of the cerebral artery. Then interpolating this
outline three-dimensionally, we generated a three-dimensional
iso-surface composed of identical CT value. Then by eliminating
unimportant branches and discontinuous segment from this
structure, we simpliied to leave only basilar tip artery and BT
aneurysm. In this way, the three-dimensional structure of basilar
tip artery was inally reconstructed from multi-slice CT information.
Figure 3.8a shows the reconstructed image of this basilar tip artery
(reconstructed area is indicated in Fig. 3.7b with dotted line;
dimension: 50 × 50 × 50 mm). Then we fabricated a tree-like lumen
structure of the basilar tip artery by means of the above-mentioned
RP modeling modality, using the reconstructed three-dimensional
geometry of basilar artery (Fig. 3.8b). Laminating pitch for the RP
modeling was set to 13 μ m.