Brain Viscoelasticity Alteration in Chronic-Progressive Multiple Sclerosis

• Published in: PloS one Vol. 7; no. 1; p. e29888
• Main Authors: Streitberger, Kaspar-Josche, Sack, Ingolf, Krefting, Dagmar, Pfüller, Caspar, Braun, Jürgen, Paul, Friedemann, Wuerfel, Jens
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 20.01.2012; Public Library of Science (PLoS)
• Subjects: Adult; Autoimmune diseases; Automation; Biology; Biomechanics; Brain; Brain - pathology; Brain - physiopathology; Brain damage; Brain research; Disease; Elasticity; Elasticity - physiology; Elasticity Imaging Techniques; Encephalitis; Female; Histopathology; Humans; Hypotheses; In vivo methods and tests; Inflammation; Magnetic resonance; Male; Medical imaging equipment; Medical research; Medicine; Middle Aged; Multiple sclerosis; Multiple Sclerosis, Chronic Progressive - pathology; NMR; Nuclear magnetic resonance; Parenchyma; Patients; Registration; Rheology; Studies; Tissues; Viscoelasticity; Viscosity; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0029888

Viscoelastic properties indicate structural alterations in biological tissues at multiple scales with high sensitivity. Magnetic Resonance Elastography (MRE) is a novel technique that directly visualizes and quantitatively measures biomechanical tissue properties in vivo. MRE recently revealed that early relapsing-remitting multiple sclerosis (MS) is associated with a global decrease of the cerebral mechanical integrity. This study addresses MRE and MR volumetry in chronic-progressive disease courses of MS. We determined viscoelastic parameters of the brain parenchyma in 23 MS patients with primary or secondary chronic progressive disease course in comparison to 38 age- and gender-matched healthy individuals by multifrequency MRE, and correlated the results with clinical data, T2 lesion load and brain volume. Two viscoelastic parameters, the shear elasticity μ and the powerlaw exponent α, were deduced according to the springpot model and compared to literature values of relapsing-remitting MS. In chronic-progressive MS patients, μ and α were reduced by 20.5% and 6.1%, respectively, compared to healthy controls. MR volumetry yielded a weaker correlation: Total brain volume loss in MS patients was in the range of 7.5% and 1.7% considering the brain parenchymal fraction. All findings were significant (P<0.001). Chronic-progressive MS disease courses show a pronounced reduction of the cerebral shear elasticity compared to early relapsing-remitting disease. The powerlaw exponent α decreased only in the chronic-progressive stage of MS, suggesting an alteration in the geometry of the cerebral mechanical network due to chronic neuroinflammation.