Master's Thesis - Studierstube Augmented Reality Project - Graz ...

4.1 Requirements
visualization of corrected four-dimensional velocity fields with additional medical image
data.
1. After a measurement sequence, all resulting images are stored in the PACS 1 in
the DICOM 2 format. Since only medical staff at facilities with PACS can access
them, we decided to export them to DVD’s or CD’s. However, this implies that we
need access to medical DICOM images and to the correlated DICOM-directories
which are generated for exported datasets. An suitable interface is therefore the
first requirement.
2. As already mentioned, most of the datasets need some preprocessing steps before
a visualization can be done. With the 4D-Flow Toolbox it is possible to correct
aliasing and baseline effects, to suppress noise and to draw segmentation contours.
The resulting velocity field is not stored in the DICOM format but in a couple
of its own files. Therefore we need to define a reader to access velocity fields in
these 4D-Flow Toolbox intermediate format files.
3. Subsequently an efficient intern administration of the available medical image
volumes and the associated velocity fields is crucial. We have to consider that
some of the data may be of interest in different parts of the resulting software but
that resources are limited on a personal computer. Furthermore most of the data
is transformed to GPU-readable 3D-textures, so we have to consider an efficient
way to administer data in GPU memory too.
4. The main objectives are interactive and highly efficient visualizations of interesting
flow patterns with a concurrent rendering of morphological background
information. The rendering of medical image volumes can be costly, so we have
to consider fast algorithms for a concurrent calculation and visualization of flow
patterns without a high CPU-load. Programs executed on the graphics unit of a
PC seem to be ideal, so we need additional support for such kinds of algorithms.
5. To provide an overview of different flow patterns for comparison reasons we have
to provide possibilities for a concurrent arrangement of different visualizations.
The same data should be presented in different ways of representation.
1 PACS = Picture Archiving and Communications System
2 DICOM = Digital Imaging and Communications in Medicine
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