Imaging stented tissue engineered blood vessel mimics

An ideal vascular stent design promotes a thin anti-thrombogenic cellular lining while avoiding restenosis. To assess the utility of their designs, stent manufactures often use destructive techniques such as scanning electron microscopy to measure the percentage of the stent covered with a cellular lining. In this study, we use a custom-built longitudinal/rotational scanning endoscope and determine the ability of optical coherence tomography (OCT) to quantify the percent cellular coverage of stented tissue engineered blood vessel mimics. Stents were deployed within twelve mimics after 14-day s of development in bioreactors. OCT images were acquired within the bioreactor at several time points after the stent deployment. At 20-days post deployment, the mimics were fixed and imaged volumetrically with OCT. Matlab software was developed to automatically calculate the percent cellular coverage from the OCT images. Algorithm results were compared to similar measurements performed with bis-benzimide (BBI) fluorescence imaging and manually calculated percent coverage from three different observers of the OCT images. Progressive accumulation of cellular material on the stents could be visualized with OCT. For the volumetric images, the algorithm calculated percent cellular coverages ranging from 11 to 76%. Good agreement was found between the OCT-based measurements and the other techniques. On average, the algorithm differed less than 5% from the manual percent coverage calculations. OCT together with automated software can provide an accurate, non-destructive measurement of the percent cellular coverage of vascular stents.