Tissue T2 relaxation time (T2 (when referring specifically to relaxation time in tissue environments))

**Tissue T2 relaxation time** represents the time constant measuring the **exponential decay of transverse magnetization** (Mxy) following excitation of tissue protons in MRI/NMR. It reflects the degree to which water protons lose phase coherence due to interactions (dipole-dipole, local field effects) within their microenvironment. T2 relaxation is generally **more rapid in solid/dense tissues** and **slower in fluids**, providing diagnostic contrast for imaging—tissues with long T2s (water/CSF, tumor, edema) appear bright on T2-weighted MRI, while those with short T2s (bone, tendons) appear dark[1][2][5][9]. T2 values vary systematically by tissue type and pathology, and changes in tissue T2 may indicate disease processes such as neuropathy, edema, or demyelination. Measurement is performed noninvasively, enabling quantification of tissue health and microstructure[3][5][9]. T2 should not be confused with T2*, which additionally reflects magnetic field inhomogeneities[4][6][8].

Other names

T2 relaxation timeSpin–spin relaxation timeTransverse relaxation timeT2 MRI signal parameter