Magnetic resonance relaxation time (null)

Magnetic resonance relaxation time refers to the time constants (T1, T2, and T2*) governing the return of proton spins (mainly hydrogen nuclei in water and fat) to equilibrium after a disturbance (radiofrequency pulse) in a magnetic field, as measured by MRI or NMR[1][3][5][7][9]. - T1 relaxation time (longitudinal or spin-lattice relaxation) describes the time taken for protons to realign with the external magnetic field, releasing energy to their environment ("lattice"). - T2 relaxation time (transverse or spin-spin relaxation) describes the time over which proton spins lose phase coherence in the plane perpendicular to the magnetic field due to interactions with other spins. - T2* relaxation time is sensitive to magnetic field inhomogeneities and local tissue properties[3][7]. These properties are not inherent to a molecule but are quantitative descriptors of tissue environments, reflecting water content, macromolecular density, local iron concentration, and pathological changes such as inflammation, edema, hemorrhage, or demyelination. They are essential for tissue contrast in MRI and serve as indirect imaging biomarkers for a broad spectrum of diseases[1][3][5][7]. Summary Judgment: "Magnetic resonance relaxation time" is a physical descriptor and not a classical biomolecular or therapeutic target. It should not be treated as a molecule, receptor, enzyme, or similar. For structured drug-target or gene-target databases, this entry is not appropriate as a canonical target and should be flagged as such.

Other names

Relaxation timeNMR relaxation timeMRI relaxation timeT1 relaxation time (longitudinal or spin-lattice)T2 relaxation time (transverse or spin-spin)T2* relaxation time

When used with contrast agents, drugs like gadolinium shorten T1 relaxation time, thereby increasing signal intensity on T1-weighted images[3]