Multimodal Optical Imaging Combined with Radiomic Analysis for Fibrotic Cardiac Tissue Investigation

Understanding the process of fibrotic scarring of the myocardium is critical for the diagnosis and risk stratification of life-threatening cardiac dysfunction. Complex changes in structure, composition, and conductivity occurring at different stages of fibrogenesis diversify the biomedical characteristics of the myocardium. We present a multimodal optical imaging approach including cardiac optical mapping (COM), optical coherence tomography (OCT), multiphoton microscopy (MPM), and line scan Raman microspectroscopy (LSRM) for multiparametric assessment of the myocardium with radiomic analysis to link electrophysiologic, morphologic, functional, and molecular changes in ischemic cardiac tissue and validate our results with histology. COM is used to map the electrical behavior across myocardial tissue. Second harmonic generation and two-photon excitation fluorescence imaging as MPM techniques provide additional unique contrast of collagen, the extracellular matrix, and cardiac cells, such as cardiomyocytes playing a critical role in cardiac fibrosis. Our machine learning model based on radiomic features extracted from MPM data addresses the need for automated fast high-throughput classification between healthy and pathologic cardiac tissues and achieved an accuracy of 0.99. In addition, LSRM assesses the molecular contrast and is used to evaluate the development stage of fibrotic scarring and multiclass classification by utilizing partial least-squares discriminant analysis, achieving sensitivity and specificity values of 0.94. OCT is used for fast navigation through the sample, for intermodal referencing, and easy coregistration between the complementary imaging techniques operating at different fields of view and resolutions ranging from cm² down to μm².