Theories
describing 1/T2 enhancement due to the presence of superparamagnetic particles
agree well with experimental and Monte Carlo (MC) simulation data under the
condition that the particles are monodisperse both in size and magnetization.
We present a 1/T2 distributed model that takes into account the particle size
and magnetization distributions. We average the individual 1/T2 components
exhibited by each group of particle with a uniform particle size. MC
simulations of the model successfully predict 1/T2 within the MAR regime confirming
the implicit assumption that the spins are able to sample all the particles’
radii and magnetizations within the echo time.
