A non-invasive optical detection system and method are provided. Sample light is delivered into a target volume of interest, whereby the sample light is scattered by the target volume of interest, resulting in a sample light pattern that exits the anatomical structure. Reference light is combined with the sample light pattern to generate at least one interference light pattern, each of which may have a time varying interference component that integrates to a first value in the absence of the physiological event, and that integrates to a second greater value in the presence of the physiological event. Intensities of spatial components of each interference light pattern are detected during a measurement period. A function of the detected spatial component intensities of the interference light pattern(s) is analyzed, and a presence of the physiological event in the target volume of interest is determined based on the analysis.
