T2* (also called T2 Star) is composed of molecular interactions (spin spin relaxation) and local magnetic field non-uniformities. Caused by this the protons precess at slightly different frequencies. The T2* effect cause a rapid loss in coherence and transverse magnetization. The T2* time is less than the T2 time.

See also T2* Time, T2 Star.

(T2 Star) The characteristic time constant that describes the decay of transverse magnetization, taking into account the inhomogeneity in static magnetic fields and the spin spin relaxation in the human body. This results in a rapid loss of phase coherence and the MRI signal. The T2* time is always less than the T2 time.

South Korea-based company, which develops and distributes MRI (Feridex I.V.) and X-ray contrast media.

MRI Contrast Agents:

Shaped pulse whose magnitude (and possibly phase) is varied with time in a predetermined manner. Affects the frequency components of a RF pulse in a manner determined by the Fourier transformation of the pulse.

Tattoos with metallic or ferromagnetic color ingredients can distort MR images. Skin irritations or burns caused by heating of the metallic particles due to the radio frequency pulse are also possible, but rare.

Patients should be informed about the possible risk, and scanning should be stopped immediately if they feel heat. Metallic make-up can even be pulled into the eye by magnetic forces and should be removed previous to the MRI scan.