50 Shades of Black, White, and Gray
Image contrast is what allows us to visualize structures and provides us a way to determine pathology in our patient. There are parameters that control these different types of image contrast(s). We will use T1, T2, PD contrast, and diffusion to try and identify pathology in our patient(s)
We will talk about the following in later lessons.
T1 contrast measures the recovery of longitudinal magnetism of each tissue in our volume. The goal is to find the greatest difference between the recovery of these tissues.
T2 contrast measure the rate of loss of transverse magnetism. This is when hydrogen starts to precess out of phase.
Proton density contrast measures the amount of net magnetism of each tissue in our volume. This is related to the amount of hydrogen in our tissues.
Diffusion imaging will identify Brownian motion in our volume. By using a bipolar gradient activation, we can measure the velocity, direction, and restriction of this motion.