Quality of clinical MR images and the use of contrast agents

Attempts to optimize the quality of magnetic resonance images must balance the competing needs for high spatial resolution, high signal-to-noise ratio, a large number of sections, and a reasonable imaging time. These factors, which determine the ultimate image quality, are affected by a number of variables, including the field of view, the matrix and pixel size, choice of repetition time and echo time, section thickness, and the number of signals averaged. The manner in which these variables interrelate and their effect on the ultimate image quality are important in order to craft the most appropriate examination for each individual patient. A second major effect on soft-tissue contrast is the use of paramagnetic agents. The spectrum of utility of these agents within the central nervous system and the body is increasing. A large number of new agents are also being investigated, primarily for use outside the central nervous system.