IMPROVED MYOCARDIAL TAGGING CONTRAST

Myocardial tagging is a new noninvasive MRI method that allows the stu dy of myocardial motion with high accuracy. However, with conventional tagging techniques tagging contrast is impaired at later heart phases due to longitudinal relaxation. An improved method, called Complement ary SPAtial Modulation of Magnetization (CSPAMM), which separates the component of the magnetization with the tagging information from the r elaxed component by subtraction of two measurements with first a posit ive and then a negative tagging grid, is presented. This technique imp roves the grid contrast and greatly facilitates the automatic evaluati on of the myocardial motion. Thus the motion assessment of the entire heart cycle becomes possible. The improvements are documented by numer ical simulations and by experiments on phantoms and on human volunteer s.