3D assessment of stent cell size and side branch access in intravascular optical coherence tomographic pullback runs.

We present a semi-automatic approach to assess the maximum circular unsupported surface area (MCUSA) of selected stent cells and the side branch access through stent cells in intravascular optical coherence tomography (IVOCT) pullback runs. Such 3D information may influence coronary interventions, stent design, blood flow analysis or prognostic evaluation. First, the stent struts are detected automatically and stent cells are reconstructed with users' assistance. Using cylinder fitting, a 2D approximation of the stent cell is generated for MCUSA detection and measurement. Next, a stent surface is reconstructed and stent-covered side branches are detected. Both the stent cell contours and side branch lumen contours are projected onto the stent surface to indicate their areas, and the overlapping regions are measured as the side branch access through these stent cells. The method was evaluated on phantom data sets and the accuracy of the MCUSA and side branch access was found to be 95% and 91%, respectively. The usability of this approach for clinical research was proved on 12 in vivo IVOCT pullback runs.