Visual Exploration of Simulated and Measured Blood Flow - Scientific Visualization: Uncertainty, Multifield, Biomedical, and Scalable Visualization - page 294

Fig. 25.3 The focus structures, the aneurysm and its immediate inflow and outflow are rendered
opaquely with highly saturated colors. Context information is shown with a less striking colour
with decreasing opacity for more distant vasculars structures
at relatively low spatial resolutions. To verify whether this behavior has occurred,
black blood scans are often employed to inspect the vessel delineation.
25.4 Visual Exploration
25.4.1 Visualization of the Anatomical Context
The visual exploration of blood flow data is usually focused on a rather small anatom-
ical region. In case of simulated blood flow data, this represents the domain where the
simulation was performed. It may be necessary to present this focus region embedded
in a somehow larger context to better understand the location of a pathology and the
in- and outflow regions. Such a visualization goal may be achieved with a coordi-
nated focus-and-context view, where the detail view presents only the target region
and the context view provides the big picture with additional anatomical context.
An integrated focus-and-context view is mentally easier to interpret. A reasonable
strategy is to employ distance-based transfer functions [ 42 ], where the distance to
the target anatomy is mapped to opacity in order to hide distant vascular structures.
This strategy is illustrated in Fig. 25.3 . The specific choice of colours and opacity as
well as the amount of information to be displayed requires careful discussions with
physicians [ 31 ]. Such a visualization may be a first step in a pipeline of exploration
and analysis, as it presents an overview and needs to be followed by a more local
analysis.