Non-Gaussian diffusion MRI of gray matter is associated with cognitive impairment in multiple sclerosis.
BACKGROUND
Non-Gaussian diffusion imaging by using diffusional kurtosis imaging (DKI) allows assessment of isotropic tissue as of gray matter (GM), an important limitation of diffusion tensor imaging (DTI).


OBJECTIVE
In this study, we describe DKI and DTI metrics of GM in multiple sclerosis (MS) patients and their association with cognitive deficits.


METHODS
Thirty-four patients with relapsing-remitting MS and 17 controls underwent MRI on a 3T scanner including a sequence for DKI with 30 diffusion directions and 3b values for each direction. Mean kurtosis (MK), mean diffusivity and fractional anisotropy (FA) of cortical and subcortical GM were measured using histogram analysis. Spearman rank correlations were used to characterize associations among imaging measures and clinical/neuropsychological scores.


RESULTS
In cortical GM, a significant decrease of MK (0.68 vs. 0.73; p < 0.001) and increase of FA (0.16 vs. 0.13; p < 0.001) was found in patients compared to controls. Decreased cortical MK was correlated with poor performance on the Delis-Kaplan Executive Function System test (r = 0.66, p = 0.01).


CONCLUSIONS
Mean kurtosis is sensitive to abnormality in GM of MS patients and can provide information that is complementary to that of conventional DTI-derived metrics. The association between MK and cognitive deficits suggests that DKI might serve as a clinically relevant biomarker for cortical injury.
Department of Diagnostic and Interventional Neuroradiology, University Medical Centre Hamburg-Eppendorf (UKE), Germany/ Department of Radiology, Langone Medical Center, NYU School of Medicine, NY, USA.
M
M
Bester
Department of Radiology and Radiological Science, Medical University of South Carolina, USA.
J H
JH
Jensen
Department of Radiology, Langone Medical Center, NYU School of Medicine, NY, USA.
J S
JS
Babb
Department of Radiology and Radiological Science, Medical University of South Carolina, USA.
A
A
Tabesh
Department of Radiology, Langone Medical Center, NYU School of Medicine, NY, USA.
L
L
Miles
Department of Neurology, Langone Medical Center, NYU School of Medicine, NY, USA.
J
J
Herbert
Department of Radiology, Langone Medical Center, NYU School of Medicine, NY, USA.
R I
RI
Grossman
Department of Radiology, Langone Medical Center, NYU School of Medicine, NY, USA/Department of Neurology, Radiology and Neuroscience, Mount Sinai School of Medicine, USA matilde.inglese@mssm.edu.
M
M
Inglese
D000328:Adult; D001921:Brain / Q000473:pathology*; D003072:Cognition Disorders / Q000209:etiology* / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D066128:Gray Matter / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000473:pathology* / Q000523:psychology; D009483:Neuropsychological Tests; D055815:Young Adult
MRI; Multiple sclerosis; cognitive impairment; diffusion; gray matter; kurtosis