Abstract: The present technique provides a novel method and apparatus for determining the motion of an internal tissue or organ undergoing dynamic movement such as a respiratory cycle. Particularly, the technique provides for a method and system for processing projection data to determine the motion rather than relying on additional data acquired from an external sensor. The motion is extracted from projection data by tracking the change over time in projections from the same projection angle and/or conjugate projection angle pairs. The extraction is possible because multiple gantry rotations occur in the time period of a single respiratory period. The motion information may in turn be used to facilitate data acquisition or image reconstruction, such as by gating techniques, to reduce or eliminate motion related artifacts.

Abstract: A method and system of CT colonography is presented that includes the acquisition of energy sensitive or energy-discriminating CT data from a colorectal region of a subject. CT data is acquired and decomposed into basis material density maps and used to differentiate and enhance contrast between tissues in the colorectal region. The invention is particularly applicable with the detection of colon polyps without cathartic preparation or insufflation of the colorectal region. The invention is further directed to the automatic detection of colon polyps.