MR correlates of cerebral atrophy in patients with multiple sclerosis.
OBJECTIVE
To investigate the in-vivo correlates of brain atrophy in patients with multiple sclerosis (MS) by assessing the relationship between normalized measures of brain volume (NBV) and other magnetic resonance (MR) measures of tissue damage.


BACKGROUND
Brain atrophy diffusely occurs and progressively increases in patients with MS. Nevertheless, the mechanisms leading to brain atrophy in this disease are not fully understood.


METHODS
MR examinations were performed in 20 patients with relapsing-remitting MS. Conventional MRI was used to assess NBV and total brain T2-hyperintense and T1-hypointense lesion volumes. Proton MR spectroscopic imaging and diffusion tensor MR imaging were also performed for large portions of brain containing mainly normal-appearing tissue to provide indices of tissue damage, including N-acetylaspartate to creatine ratio (NAA/Cr) and mean diffusivity (D).


RESULTS
Values of NBV correlated significantly with those of average brain (r = -0.58, p = 0.007) and NAA/Cr (r = 0.67, p < 0.001). The relationship of these markers of tissue damage to NBV was also found when NAA/Cr and were computed together in a composite MR score (r = 0.70, p < 0.001). In contrast, NBV values did not correlate with measurements of average lesion, T(2) and T(1) weighted total brain MRI lesion volumes.


CONCLUSIONS
This study suggests that brain atrophy in MS is not simply due to axonal loss, but rather reflects a more generalized process that involves various brain tissue components. Damage to the normal-appearing tissue rather than the extent and intrinsic pathology of macroscopic lesions seems to be important in the destructive process leading to MS-related irreversible cerebral atrophy.
Institute of Neurological Science, Viale Bracci 2, 53100, Siena, Italy. destefano@unisi.it
Nicola
N
De Stefano
Giuseppe
G
Iannucci
Maria P
MP
Sormani
Leonello
L
Guidi
Maria L
ML
Bartolozzi
Giancarlo
G
Comi
Antonio
A
Federico
Massimo
M
Filippi
D000328:Adult; D001284:Atrophy; D001921:Brain / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000000981:diagnostic imaging* / Q000473:pathology*; D011859:Radiography