Perivenular brain lesions in a primate multiple sclerosis model at 7-tesla magnetic resonance imaging

Background. Magnetic resonance imaging (MRI) can provide in vivo assessment of tissue damage, allowing evaluation of multiple sclerosis (MS) lesion evolution over time - a perspective not obtainable with postmortem histopathology. Relapsing-remitting experimental autoimmune encephalomyelitis (EAE) is an experimental model of MS that can be induced in the common marmoset, a small new world primate, and that causes perivenular white matter (WM) lesions similar to those observed in MS. Methods. Brain lesion development and evolution were studied in vivo and postmortem in four marmosets with EAE through serial T2- and T2-weighted scans at 7-tesla. Supratentorial WM lesions were identified and characterized. Results. Of 97 lesions observed, 86 (88%) were clearly perivenular, and 62 (72%) developed around veins that were visible even prior to EAE induction. The perivenular configuration was confirmed by postmortem histopathology. Most affected veins, and their related perivascular Virchow-Robin spaces, passed into the subarachnoid space rather than the ventricles. Conclusion. As in human MS, the intimate association between small veins and EAE lesions in the marmoset can be studied with serial in vivo MRI. This further strengthens the usefulness of this model for understanding the process of perivenular lesion development and accompanying tissue destruction in MS.