Nuclear magnetic resonance phenomena provide the basis for a rich set of methods for assessing anatomy and function in the living organism. The objective of Dr. Ehman's program is to expand the range of tissue, organ, and system characteristics that can be noninvasively evaluated with magnetic resonance imaging (MRI) techniques.

These studies include investigation of new methods for high resolution magnetic resonance imaging of moving structures, techniques of ultrafast MR imaging, and methods for noninvasive mapping of the vascular system, especially the coronary arteries. Studies of the basic physics of motion effects in the MR data acquisition process have lead to the development of "Navigator echo" imaging techniques that are highly suited for resolving structures that are in motion.

Other studies employ MRI to quantitatively assess vascular flow characteristics such as velocity, volumetric rates, and disordered flow or turbulence.

Research is directed at developing novel MR techniques to probe bone trabecular morphology, to measure cellular organization in space, and to noninvasively delineate the mechanical properties of the tissue. The objective of the latter project is to develop a technique for "palpation by imaging" to detect cancer and other tissue abnormalities a an early stage. The research employs MRI to directly image propagating acoustic waves in tissues, allowing images of viscoelastic properties to be generated.