Longitudinal Study Of T₁ HypoIntense Lesions In Relapsing MS:
MSCRG Trial Of Interferon-ß-1a

Background
T₁ HypoIntense lesions (T₁ Black Holes) are Focal areas of relatively severe CNS tissue damage detected by MRI in patients with MS.

Objective
To determine the natural history of T₁ HypoIntense lesions in Relapsing MS and the utility of T₁ HypoIntense lesions as outcome measures in MS clinical trials.

Methods
MR studies were from the Multiple Sclerosis Collaborative Research Group Trial.

Longitudinal results are reported in 80 placebo- and 80 Interferon beta-1a (IFN-ß-1a)-treated patients with mild to moderate disability Relapsing/Remitting MS.

Results
There was a small but significant correlation between T₁ HypoIntense lesion volume and Disability at baseline and on trial (r = 0.22, r = 0.28).

In placebo patients there was a 29.2% increase in the mean volume of T₁ HypoIntense lesions (median 124.5 mm3) over 2 years (p < 0.001 for change from baseline), as compared to an 11.8% increase (median 40 mm3) in the IFN-ß-1a-treated patients (change from baseline not significant).

These treatment group comparisons did not quite reach significance. The most significant contributor to change in T₁ HypoIntense lesions was the baseline number of enhancing lesions (model r2 = 0.554).

Placebo patients with more active disease, defined by enhancing lesions at baseline, were the only group to show a significant increase in T₁ HypoIntense lesion volume from baseline.

Conclusion
The development of T₁ HypoIntense Lesions is strongly influenced by prior Inflammatory disease activity, as indicated by enhancing lesions.

These results suggest that treatment with once weekly IM IFN-ß-1a (30 mcg) slows the 2-year accumulation of these lesions in the Brain.