T1-weighted spin echo. T1 and T2 relaxation curves for a T1-weighted spin echo pulse sequence (180° pulse not shown) over two repetition periods and for three different tissues. The short TR leads to different amounts of recovery of the z-magnetisation for the three tissues, leading to T1-based contrast. The short TE minimises differences due to differences in T2 relaxation. T1-weighted images are characterised by bright fat and low signal intensity from static fluid.