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MAgnetic
Resonance Angiography Computer Assisted analysiS: An Interactive Software for Visualization
and Analysis of Blood Vessels in 3D MRA Providing Automatic Quantification of
the Arterial Stenosis
MARACAS
is an assistance tool for the diagnosis, treatment planning and follow-up of
arterial diseases. It combines the most commonly used three-dimensional
visualization techniques with original image processing methods applied to the
analysis of vascular morphology in MRA. MARACAS functionality includes:
·
Series and
volume of interest selection.
·
3D vessel
tracking and automatic quantification.
Series and
volume of interest selection
When MARACAS is started, the Patient List window appears (Fig. 1). This
window enables the user to retrieve and load image data. MARACAS automatically
reads and displays patient and scanner information included in the DICOM
header. Each patient can include multiple series of image data. Hence, when the
user selects a patient, its constitutive series are listed.
Figure 1 – Patient
List window
One series can be selected and then displayed in a normal size in the Series
window (Fig. 2). Once the images are loaded, MARACAS gives access to a vast
array of manipulation tools, including slice-by-slice visualization, zoom, as
well as contrast control by window width and level adjustments. In order to
reconstruct, from a slice series, the 3D volume of interest (VOI) to be
processed, the user needs to select the first and the last slice to be included
in the volume. Then, he/she can delimitate the region to be analyzed (i.e.
pathological region).
Figure 2 – Series window.
3D visualization
Once the 3D VOI is reconstructed, it is displayed in the 3D
Visualization window by means of a surface rending technique (Fig. 3). It can
be performed from any viewing angle, panned and zoomed.
Figure 3 - 3D visualization
window.
3D vessel tracking and automatic
quantification
Vessel-tracking process is divided into two steps. First, the extraction
of the vessel central axis is performed. Contours are then detected in the
planes locally orthogonal to the centerline. See the "description
of the method" for more details.
MARACAS supplies automatic measurements aimed at an accurate quantitative
analysis of vascular morphology. (Fig. 4).
Figure 4 - Automatic
quantification along the vessel centerline.