Exemplary method and apparatus for diagnosing or characterizing an inflammation within an anatomical structure can be provided. For example, using at least one source arrangement, it is possible to provide at least one first electro-magnetic radiation to the anatomical structure at at least one first wavelength in vivo. With at least one detector arrangement, it is possible to detect at least one second electro-magnetic radiation at at least one second wavelength provided from the anatomical structure. The second radiation can be associated with the first radiation, and the first wavelength can be shorter than the second wavelength. The second radiation can be provided from the anatomical structure due to at least one change in the anatomical structure caused by the inflammation without providing an artificial fluorescence substance. At least one computer arrangement can be used to determine at least one characteristic of the structure based on the second radiation to diagnose or characterize the inflammation within the anatomical structure.