An intravascular optical coherence tomography technique for in vivo carotid intima-media thickness measurement and mechanical characterization

Abstract

Arterial characteristic parameters including the intima-media thickness (IMT), strain, strain rate, elastic modulus, and compliance may be unevenly distributed due to local lesion growth. Thus, a combination of the full-field distribution of these parameters may provide more effective guidance for the diagnosis and treatment of vascular diseases than either one of them. Here, we develop an intravascular coherence tomography (IVOCT) based full-field measurement method to characterize the mechanical properties of carotid artery in vivo. Image processing methods are proposed based on U-Net model and centroid detection for accurate IMT measurement. The strain, strain rate, incremental elastic modulus and volumetric compliance are obtained based on the geometric changes of intima-media. Ex vivo silica gel phantom tests demonstrate the accuracy of the vascular wall segmentation by the U-Net based method is greater than 92%, and the error for elastic modulus measurement is less than 2%. A porcine carotid artery was imaged by IVOCT in vivo, and the IMT and the mechanical characteristics during cardiac cycle were measured. The proposed method facilitates the study of the uneven pathological evolution of the vascular wall and provides an effective measurement method for the study of vascular mechanical properties in vivo.