T2-weighted spin echo. T1 and T2 relaxation curves for a T2-weighted spin echo pulse sequence (180° pulse not shown) for three different tissues. The long TR minimises differences due to differences in T1 relaxation. The long TE leads to different amounts of decay of the xy-magnetisation for the three tissues, leading to T2-based contrast. T2-weighted images are characterised by bright fluid and low signal intensity from muscle.