High contrast and fast three-dimensional magnetic resonance imaging at high fields.

A new three-dimensional imaging strategy based on magnetization prepared ultrafast gradient recalled echo technique that demonstrates pronounced T1 contrast at high fields is introduced. High-resolution three-dimensional image sets of human brain showing high contrast between white and gray matter areas are presented. The ratio of contrast-to-noise was examined as a function of the relevant parameters in the imaging sequence; calculations based on high-field T1 values as well as the experimental data demonstrated that maximal contrast-to-noise ratio is attained under the same magnetization preparation conditions both for cortical and subcortical gray matter relative to white matter, leading to approximately equivalent appearance of all gray matter areas in the same image. In addition, the images displayed clear visualization of subtle anatomical structures such as the subthalamic nuclei (ventral tier nuclei, dorsomedial nucleus, and pulvinar) and mammillothalamic tracts.