Contrast: Difference between different regions
TR: repetition time, affect longitudinal
magnetization.
TE: echo time, affect transverse magnetization.
In general,
==> Long TR, short TE --> density-weighted
Short TR, short TE --> T1-weighted
Long TR, long TE --> T2-weighted
Different tissues ~ different environment for protons
detected.
T1, T2 are field dependent. At B0 = 1.5-2 T,
T1: 100ms (fat), 500ms (liver), 1000ms (brain), 2000ms
(CSF)
T2: 20ms (muscle), 50ms (liver), 100ms (brain), 500ms
(CSF)
FOV (field-of-view): spatial coverage of image in each
direction
resolution: number of points in image (typically
256x256)