Image post-processing
The DICOM format of high-quality 3D-TEE ASD
images at the isovolumetric
diastole stored in the EchoPAC workstation were imported into
specialized post-processing software Mimics Innovation Suite 17.0
(Materialise, Leuven, Belgium), where the source imaging datasets can be
converted to 3D digital models (Fig.1B ). Various
post-processing methods including threshold segmentation, interactive
segmentation and surface smoothing were used to create an accurate 3D
digital ASD model. Firstly, threshold segmentation was applied to
distinguish the blood pool border of the ASD from the endocardium, from
which the blood pool could be filtered and the mask of the ASD were
obtain initially. The threshold was adjusted with reference to the
endocardial in different cases. After threshold segmentation, there
still exist much noise and dropout gaps of the mask, manual editing is
necessary to correct segmentations errors. Interactive segmentation was
utilized to artificially exclude the noise and fill of the dropout gaps.
Finally, surface smoothing function key was used to smooth the surface
of the anatomy before exporting to the software 3-matic(Materialise,
Leuven, Belgium), where the ASD mask could be calculated for a 3D
hollow mold. (Fig. 1C )