What is the term for transverse magnetization decay?

What is the term for transverse magnetization decay?

• A. T2
• B. T1
• C. T2*
• D. T1rho

Answer: (A)

Transverse magnetization decay is described by T2 relaxation. After excitation, spins lose phase coherence with each other due to spin–spin interactions, and the transverse signal decays exponentially with time constant T2. This decay is intrinsic to the tissue and largely independent of magnetic field inhomogeneities. In real imaging, extra dephasing from field inhomogeneities adds to this decay, giving the apparent rate T2*, which is always faster than T2. Other relaxation processes include T1, which is the recovery of longitudinal magnetization along the main field, and T1rho, relaxation in the rotating frame during a spin-lock. So the term for transverse magnetization decay is T2.