What is the transverse relaxation time?

What is the transverse relaxation time?

The transverse, or spinâ€“spin, relaxation time is related to the lifetime of the magnetization component in the plane perpendicular to the magnetic field direction, which is zero at equilibrium.

What is T2 relaxation in NMR?

T2 relaxation, also known as spin-spin relaxation or transverse relaxation, refers to the progressive dephasing of spinning dipoles resulting in decay in the magnetization in the transverse plane (Mxy).

How is T2 relaxation time calculated?

Mathematically, T2 is defined by the equation Magxy/Magxy_max = e -t/T2, and is measured by fitting the observed loss of magnetization in the xy plane over time to an exponential .

What is relaxation delay in NMR?

The time period between scans is called the relaxation delay (or the pulse delay). Two 90o pulses, with sufficient time between them for full relaxation, produce a total signal with twice the intensity of that generated by one pulse.

What is meant by transverse relaxation?

An MRI term for the time constant, T2, which determines the rate at which excited protons fall to equilibrium or go out of phase with each other.

What is the difference between longitudinal and transverse relaxation?

Transverse relaxation results from spins getting out of phase. As spins move together, their magnetic fields interact (spin-spin interaction), slightly modifying their precession rate. These interactions are temporary and random. Transverse relaxation is faster than longitudinal relaxation.

What is T2 decay time?

As originally described by Felix Bloch (1946), T2 relaxation is considered to follow first order kinetics, resulting in a simple exponential decay (like a radio-isotope) with time constant T2. Thus T2 is the time required for the transverse magnetization to fall to approximately 37% (1/e) of its initial value.

Is T2 flair normal?

White matter hyperintensities (WMH) lesions on T2 and fluid attenuated inversion recovery (FLAIR) brain MRI are very common findings in elderly cohorts and their prevalence increases from 15% at the age of 60 to 80% at the age of 80 [1-4].