Image Registration for Simultaneous Membrane Potential and Intracellular Calcium in Rabbit Hearts

摘要

This paper is concerned with the measurement system that optically records simultaneously membrane potential (V_m) and intracellular calcium (Ca_~(2+)) signals from a surface of Langendorff-perfused rabbit hearts, stained with voltage sensitive and calcium sensitive dyes. There are several publications about optical mapping system that deal with dual measurement, however the registration method used and evaluation accuracy is not explained in detail: most of the time it is just mentioned shortly and briefly. In addition, in order to be able to study different arrhythmia phenomena with accuracy, there is a necessity for simultaneous measurement using optical mapping system with high spatial and temporal resolution. In this paper, a new methodology in regard to the actual existing registration methods, which allow simultaneous measurement of two dynamic parameters from the same part of the heart, is developed, consisting of camera calibration, corresponding point-based registration using laser and Mutual information as a registration method for alignment respective optical fluorescence images. Evaluation of the registration of experimental data set in the Langendorff perfused rabbit heart, reveals that the accuracy of the registration obtained was RMSE= 1.39 ± 0.70 pixel on Experimental data set 1 and RMSE = 0.76 ± 0.38 pixel on Experimental data set 2, on the alignment process of the images.