Optical Coherence Tomography for Patient-specific 3D Artery Reconstruction and Evaluation of Wall Shear Stress in a Left Circumflex Coronary Artery
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Cardiovascular Engineering and Technology
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Image-based computational models for quantifying hemodynamic indices in stented coronary arteries often employ biplane angiography and intravascular ultrasound for 3D reconstruction. Recent advances in guidewire simulation algorithms and the rise of optical coherence tomography (OCT) suggest more precise coronary artery reconstruction may be possible. We developed a patient-specific method that combines the superior resolution of OCT with techniques for imaging wire pathway reconstruction adopted from graph theory. The wire pathway with minimum bending energy was determined by applying a shortest path algorithm to a graph representation of the artery based on prior studies indicating a wire adopts the straightest configuration within a tortuous vessel. Segments from OCT images are then registered orthogonal to the wire pathway using rotational orientation consistent with geometry delineated by computed tomography (CT). To demonstrate applicability, OCT segments within the stented region were combined with proximal and distal CT segments and imported into computational fluid dynamics software to quantify indices of wall shear stress (WSS). The method was applied to imaging data of a left circumflex artery with thrombus acquired immediately post-stenting and after a 6-month follow-up period. Areas of stent-induced low WSS returned to physiological levels at follow-up, but correlated with measurable neointimal thickness in OCT images. Neointimal thickness was negligible in areas of elevated WSS due to thrombus. This novel methodology capable of reconstructing a stented coronary artery may ultimately enhance our knowledge of deleterious hemodynamic indices induced by stenting after further investigation in a larger patient population.