Transverse relaxation time

The transverse relaxation time (also called T2 relaxation time) is an element of the Bloch equations for describing nuclear and electron magnetization. It is the time constant of the exponential decrease of the transverse magnetization after switching off the RF alternating field in magnetic resonance tomography .

${\displaystyle {\text{Signal}}\propto \exp \left(-{\frac {t}{T_{2}}}\right)}$

The cause is the energy exchange between spins at high and low energy levels (therefore also called spin-spin relaxation), without energy being given off to the environment as is the case with spin-lattice relaxation .