Normal-appearing grey and white matter T1 abnormality in early relapsing-remitting multiple sclerosis:: a longitudinal study

Objective To investigate the presence and evolution of T-1 relaxation time abnormalities in normal-appearing white matter (NAWM) and grey matter (GM), early in the course of relapsing-remitting multiple sclerosis (MS). Methods Twenty-three patients with early relapsing-remitting MS and 14 healthy controls were imaged six monthly for up to three years. Mean follow-up was 26 months for MS patients and 24 months for controls. Dual-echo fast-spin echo and gradient-echo proton-density and T-1-weighted data sets (permitting the calculation of a T-1 map) were acquired in all subjects. GM and NAWM T-1 histograms were produced and a hierarchical regression model was used to investigate changes in T-1 over time. Results At baseline, significant patient-control differences were seen, both in NAWM (P<0.001) and in GM (P=0.01). At follow-up, there was no evidence for a serial change in either mean T-1 or peak-location for either NAWM or GM. There was weak evidence for a decline in patient NAWM peak-height and also evidence for a decline in control GM peak-height. Conclusion There are significant and persistent abnormalities of NAWM and GM T-1 in early relapsing-remitting MS. Further studies should address whether such T-1 measures have a role in prognosis or therapeutic monitoring.