Automated region of interest analysis of dynamic Ca~(2+) signals in image sequences

摘要

Relative cellular Ca~(2+) levels are commonly measured as time lapse image sequences using fluorescent Ca~(2+) indicators, such as Fluo-4 (2,10, 12,15-16, 21-22, 26-27,29-31). These image sequences are often analyzed with user-defined regions of interest (ROIs) at sites determined to have fluctuations in fluorescence intensity, and the mean intensity within each ROI is measured as a function of time (2, 8-11,15, 29-31). Current ROI-based Ca~(2+) measurements are both time consuming and labor intensive because they require the user to select many ROIs individually and perform repetitive computations (18-20, 25). Manual ROI placement may also be prone to considerable user error, including the introduction of artificial signal modes and the loss of signal modes due to the exclusion of low amplitude or diffuse signals (20, 32).