Defined Terms:
Computer Calculated Reference
Interpolated Local Reference
Mean Local Reference
The computer-defined obstruction analysis calculates the reconstruction diameter based on the diameters outside the stenotic segment. This method is completely automated and user independent. The reconstructed diameter represents the diameters of the artery had the obstruction not been present.
The proximal and distal borders of the stenotic segment are automatically calculated.
The difference between the detected contour and the reconstructed contour inside the reconstructed diameter contour is considered to be the plaque.
Based on the reconstruction diameter at the Minimum Luminal Diameter (MLD) position a reference diameter for the obstruction is defined.
The interpolated reference obstruction analysis calculates a reconstruction diameter for each position in the analyzed artery. This reconstructed diameter represents the diameters of the artery when no disease would be present. The reconstruction diameter is a line fitted through at least two user-defined reference markers by linear interpolation.
By default two references are used at the positions of the reference markers are automatically positioned at 5% and 95% of the artery length.
To calculate a percentage diameter stenosis the reference diameter for the obstruction is defined as the reconstructed diameter at the position of the MLD.
In cases where the proximal and distal part of the analyzed artery have a stable diameter during the treatment and long-term follow-up, this method will produce a stable reference diameter for all positions in the artery.
In case of mean local reference obstruction the reference diameter will be an average of the diameters at the position of one or more the reference markers.
This method is particularly appropriate for the analysis of bifurcated arteries.