TR and TE

TR and TE are basic pulse sequence parameters and stand for repetition time and echo timerespectively. They are typically measured in milliseconds (ms).


The echo time (TE) represents the time from the center of the RF-pulse to the center of the echo. For pulse sequences with multiple echoes between each RF pulse, several echo times may be defined and are commonly noted TE1, TE2, TE3, etc.

The repetition time (TR) is the length of time between corresponding consecutive points on a repeating series of pulses and echoes.