Objectives: To investigate changes of abnormal phase in subcortical deep-gray matter (SDGM) and volume/number of visible lesions on SWI-filtered phase in patients with relapsing–remitting MS receiving interferon β-1a (IFN β-1a) vs. untreated healthy controls (HCs) who completed a 24-week study.
Methods: Twenty-three patients who received IFN β-1a subcutaneously for 6 months and 15 HCs were imaged on a 3T scanner at baseline, 12 weeks, and 24 weeks (NCT01085318). Mean phase of the abnormal phase tissue was determined for total SDGM, caudate, putamen, globus pallidus, thalamus, pulvinar nucleus, hippocampus, amygdala, nucleus accumbens, red nucleus, and substantia nigra. Changes in lesion number and volume visible on SWI-filtered phase images were assessed over 24 weeks. Between and within abnormal phase changes over follow-up were tested using non-parametric statistics adjusted for multiple comparisons.
Results: At baseline, patients showed significantly decreased abnormal phase in caudate (p=0.001), total SDGM (p=0.003) and putamen (p=0.008), compared with HCs. A trend for decreased abnormal phase was detected in thalamus, pulvinar nucleus and globus pallidus (p<0.05). Changes in abnormal phase between patients and HCs, or within individual groups, were not significant for any SDGM region over 24 weeks. However, there was a significant decrease of lesion volume (p<0.001) and number (p=0.003) of lesions visible on SWI-filtered phase images in patients over 24 weeks.
Conclusions: Over 24 weeks, IFN β-1a-treated patients experienced a similar change in iron content compared to HCs. In patients, IFN β-1a significantly decreased the number and volume of visible lesions on SWI-filtered phase over follow-up.