Brain Advance Access published online on August 1, 2008
Brain, doi:10.1093/brain/awn171
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Perivascular spaces—MRI marker of inflammatory activity in the brain?
1Cecilie Vogt Clinic for Neurology in the HKBB, Charité – Universitaetsmedizin Berlin, 2Dr Senckenbergische Anatomie, Institute of Clinical Neuroanatomy, Goethe University, Frankfurt and 3Sostana GmbH and Charité – Universitaetsmedizin Berlin, Germany
Correspondence to:
Prof. Dr F. Zipp, Scientific Director of the Cecilie Vogt Clinic for Neurology in the HKBB, Charitéplatz 1, Charité – Universitaetsmedizin Berlin, 10117 Berlin, and Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany E-mail: frauke.zipp{at}charite.de
The Virchow–Robin spaces (VRS), perivascular compartments surrounding small blood vessels as they penetrate the brain parenchyma, are increasingly recognized for their role in leucocyte trafficking as well as for their potential to modulate immune responses. In the present study, we investigated VRS numbers and volumes in different brain regions in 45 multiple sclerosis patients and 30 healthy controls of similar age and gender distribution, applying three different MRI sequence modalities (T2-weighted, T1-weighted and FLAIR). VRS were detected in comparable numbers in both multiple sclerosis patients and healthy individuals, indicating that perivascular compartments present on MRI are not a unique feature of multiple sclerosis. However, multiple sclerosis patients had significantly larger VRS volumes than healthy controls (P = 0.004). This finding was not explained by a significantly lower brain parenchymal fraction (BPF), resulting from a higher degree of atrophy, in the patient cohort. In a multiple linear regression analysis, age had a significant influence on VRS volumes in the control group but not in multiple sclerosis patients (P = 0.023 and P = 0.263, respectively). A subsequent prospective longitudinal substudy with monthly follow-up MRI over a period of up to 12 months in 18 patients revealed a significant increase in VRS volumes and counts accompanying the occurrence of contrast-enhancing lesions (CEL). At time points when blood–brain barrier (BBB) breakdown was indicated by the appearance of CEL, total VRS volumes and counts were significantly higher compared with preceding time points without CEL (P = 0.011 and P = 0.041, respectively), whereas a decrease thereafter was not statistically significant. Thus, our data points to an association of VRS with CEL as a sign for inflammation rather than with factors such as age, observed in healthy controls, and therefore suggests a role of VRS in inflammatory processes of the brain.
Key Words: perivascular spaces; Virchow–Robin spaces; multiple sclerosis; MRI; neuroinflammation
Abbreviations: BBB, blood–brain barrier; BPF, brain parenchymal fraction; CEL, contrast-enhancing lesion; CNS, central nervous system; CSF, cerbrospinal fluid; EAE, experimental autoimmune encephalomyelitis; EDSS, expanded disability status scale; FLAIR, fluid-attenuated inversion recovery; IFN-β, interferon-beta; VRS, Virchow–Robin spaces
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Received April 7, 2008. Revised July 4, 2008. Accepted July 4, 2008.
*These authors contributed equally to this work
These authors contributed equally to this work