1. An imaging system comprising: an illumination system configured to illuminate a region of interest (ROI) of a brain of a subject under test (SUT), the ROI having at least one blood vessel, and a reference blood vessel with photons and receive the photons after interaction with the ROI and the reference blood vessel; a light detection mechanism including an optical detector and a signal processing section, the light detection mechanism configured to acquire the photons after interaction thereof with the ROI and the reference blood vessel to compile first imaging data representing the ROI and second imaging data representing the reference blood vessel; a processor, in operable communication with the light detection mechanism, configured to process the first and second imaging data to determine a first shape parameter of a hemodynamic pulse in the at least one blood vessel and a second shape parameter of a hemodynamic pulse in the reference blood vessel; a display section, in which appears a display of at least one image representing the first shape parameter of a hemodynamic pulse in the at least one blood vessel; and tangible, non-transitory storage medium containing program code which, when downloaded on said processor, causes the processor to determine the first shape parameter from processing of the first imaging data; to determine the second shape parameter based on processing of the second imaging data; to compare said first and second shape parameters to determine a difference therebetween; to transform the first imaging data to create said at least one image showing a distribution of the first shape parameter in a cross-section of the ROI; and to form output data representing elasticity of said at least one blood vessel from the ROI based on said difference and said at least one image.