Diffusion Tensor Imaging of Post Mortem Multiple Sclerosis Brain

By K. Schmierer, Claudia A. M. Gandini Wheeler-Kingshott, Philip A. Boulby, F. Scaravilli, D. Altmann, Gareth J. Barker, P. Tofts, David H. Miller. NeuroImage, 2006

392 citations recorded by the source corpus.

Magnetic resonance imaging (MRI) is being used to probe the central nervous system (CNS) of patients with multiple sclerosis (MS), a chronic demyelinating disease. Conventional T2-weighted MRI (cMRI) largely fails to predict the degree of patients' disability. This shortcoming may be due to poor specificity of cMRI for clinically relevant pathology. Diffusion tensor imaging (DTI) has shown promise to be more specific for MS pathology. In this study we investigated the association between histological indices of myelin content, axonal count and gliosis, and two measures of DTI (mean diffusivity [MD] and fractional anisotropy [FA]), in unfixed post mortem MS brain using a 1.5-T MR system. Both MD and FA were significantly lower in post mortem MS brain compared to published data acquired in vivo. However, the differences of MD and FA described in vivo between white matter lesions (WMLs) and normal-appearing white matter (NAWM) were retained in this study of post mortem brain: average MD in WMLs was 0.35×10−3 mm2/s (SD, 0.09) versus 0.22 (0.04) in NAWM; FA was 0.22 (0.06) in WMLs versus 0.38 (0.13) in NAWM. Correlations were detected between myelin content (Trmyelin) and (i) FA (r=−0.79, p<0.001), (ii) MD (r=0.68, p<0.001), and (iii) axonal count (r=−0.81, p<0.001). Multiple regression suggested that these correlations largely explain the apparent association of axonal count with (i) FA (r=0.70, p<0.001) and (ii) MD (r=−0.66, p<0.001). In conclusion, this study suggests that FA and MD are affected by myelin content and – to a lesser degree – axonal count in post mortem MS brain.

Subfields: Pathology and Forensic Medicine, Radiology, Nuclear Medicine and Imaging

View Paper: https://www.semanticscholar.org/paper/874b52582f160b211eb83a9c034e3ca669fcabcc

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Citations in the corpus

Radial Diffusivity Predicts Demyelination in ex-vivo Multiple Sclerosis Spinal Cords (2011, positive): “In human brain, λ ∣∣ , λ ⊥ and mean diffusivity were decreased in unfixed ex vivo brain compared to in vivo conditions and dropped further following fixation while FA remained unchanged (Schmierer et al., 2007).”
Life-span changes of the human brain white matter: diffusion tensor imaging (DTI) and volumetry. (2010, background): “Also, histological analyses indicate FA and MD sensitivity to myelin content, and to a lesser degree axonal count (Schmierer et al. 2007).”
Regional specificity of MRI contrast parameter changes in normal ageing revealed by voxel-based quantification (VBQ) (2011, background): “In view of the possible physical and physiological confounds of studies correlating post mortem DTI and histology (D'Arceuil and de Crespigny, 2007; Schmierer et al., 2007) our interpretation of age-related FA and MD changes inWM builds on a recent study comparing in vivo DTI measures with…”
Longitudinal Development of Human Brain Wiring Continues from Childhood into Adulthood (2011, background): “Although biophysical processes associated with normal human development are more complex than in these animal models (Schmierer et al., 2007; Concha et al., 2010), the decreased observed here suggests increased myelination and/or more densely packed axons with age.”