Quantitative Analysis of Multiple Sclerosis by Means of MRI

Abstract

In comparison with the healthy white matter (WM), lesions of multiple sclerosis (MS) are characterized by a prolongation of T2. For this reason, MRI offers better visualization of MS plaques than does CT. In living tissue the T2 relaxation decay depends on interpulse delays τ, of the CPMG sequences, due to diffusion and molecular exchange processes. Recorded by the 2DFT method with a long τ (>20 ms), the T2 decay can only be fitted on a monoexponential pattern. But using CPMG sequences with τ values as short as 6 ms, which improves the temporal resolution, the decay curves of some tissues become biexponential, with a short T2 (T2s) characterizing an intracellular space and a long T2 (T21) characterizing an extracellular space like cerebrospinal fluid infiltration or edema.