Optical Fluorescence: Application of Structured Light Illumination and Compressed Sensing to High-speed Laminar Optical Fluorescence Tomography

Abstract

Spiral wave is known as a cause of arrhythmia. However, there is no report that a filament that is the center of the spiral wave (SW) in three dimensions was experimentally observed. Obtaining sufficient recording speed to observe cardiac excitation propagation remains a major challenge. We proposed an optical method called Compressed LOT (CLOT) which adapted compressed sensing to Laminar Optical Tomography (LOT) in order to estimate the three-dimensional membrane potential distribution inside the myocardial tissue. We examined the performance of the proposed method of identifying the location of SW three-dimensional membrane potential reconstructed with CLOT in simulation. We used phase variance analysis for the determination of SW filament. Obtained results show that the method can estimate the location of SW filaments up to 2.5 mm depth. We also constructed an experiment system to verify the principle of CLOT using optical phantoms containing fluorophores. We used a digital mirror device (DMD) with high-speed pattern switching capability (with an interval of 1 ms). Optical phantom mimicking biological tissue with fluorophore was prepared. Fluorescent dye contained in a capillary with an internal diameter of 1.4 mm was immersed in light scattering and absorbing medium contained intralipid. Reconstruction accuracy at the deep position (depth: 1.875 mm) was less than 04 mm. It is considered that accurate measurement of the optical constant is required for better reconstruction accuracy.