Open Access
Disappearing "T1 black holes" in an animal model of multiple sclerosis
Istvan Pirko1,Aaron Johnson1,Jeff Gamez1,Slobodan I Macura1,Moses Rodriguez1
Department of Neurology, Mayo Clinic and Foundation, 200 First Street Southwest, Rochester, MN 55905, USA
DOI: 10.2741/1322 Volume 9 Issue 2, pp.1222-1227
Published: 01 May 2004
(This article belongs to the Special Issue Inflammatory disorders of the nervous system)

Brain MRI in multiple sclerosis (MS) frequently shows areas of hypointensity in the white matter on T1 weighted sequences ("T1 black holes"). These areas are thought to be consistent with irreversible axonal loss. In this study T1 black holes were characterized in Theiler's Murine Encephalitis Virus infection, an established model of demyelinating diseases in mice. The spectrum of TMEV is broad in different strains. C57BL/6J mice develop a self-limited brain disease, which resolves within 4-6 weeks. We followed six mice with serial MRI and MRS on days 0, 3,7,21 and 45. The studies were performed in a 7 Tesla magnet. Periventricular and parahippocampal T1 black holes seen as early as 3 days, with decreasing NAA/Cre ratio on MRS. The extent of pathology was most severe on days 3 and 7. T1 black holes are thought to be consistent with areas of irreversible axonal loss. This is challenged by our observations of resolution of T1 black holes by day 45. This was concomitant with the normalization of MRS findings in the areas of interest. We conclude that T1 black holes may represent a transient phenomenon in this model of MS. The recovery of these areas studied suggests an active repair mechanism.

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Istvan Pirko, Aaron Johnson, Jeff Gamez, Slobodan I Macura, Moses Rodriguez. Disappearing "T1 black holes" in an animal model of multiple sclerosis. Frontiers in Bioscience-Landmark. 2004. 9(2); 1222-1227.