Classification of mild cognitive impairment and Alzheimer disease using model-based MR and magnetization transfer imaging.
OBJECTIVE
Early stratification of degenerative processes is a prerequisite to warrant therapeutic options in prodromal Alzheimer disease. Our aim was to investigate differences in cerebral macromolecular tissue composition between patients with AD, mild cognitive impairment, and age- and sex-matched healthy controls by using model-based magnetization transfer with a binary spin-bath magnetization transfer model and magnetization transfer ratio at 1.5 T.


METHODS
We investigated patients with de novo AD (n=18), MCI (n=18), and CTRLs (n=18). A region-of-interest analysis of the entorhinal cortex, hippocampal head and body, insula, and temporal neocortex was performed with fuzzy clustering to associate every subregion to a cluster representative for each group.


RESULTS
Cluster analysis achieved a concordance of 0.92 (50 of 54 subjects) between a combination of the calculated mMT parameters (kf,kr,T2r,F,T2f) in the entorhinal cortex and the neuropsychological diagnosis. The sensitivity and specificity for the discrimination of AD from MCI reached 1 and 0.94, with a positive predictive value of 0.95 and a negative predictive value of 1. Compared with mMT, the concordance for MTR was 0.83 (45 of 54 subjects) with a lower specificity of 0.5 and positive predictive value of 0.67 to discriminate patients with AD and MCI.


CONCLUSIONS
mMT imaging detects macromolecule-related alterations and allows an improved classification of patients with early AD and MCI compared with MTR.
Support Center for Advanced Neuroimaging, University Institute of Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
R
R
Wiest
Y
Y
Burren
M
M
Hauf
G
G
Schroth
J
J
Pruessner
M
M
Zbinden
K
K
Cattapan-Ludewig
C
C
Kiefer
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000145:classification* / Q000473:pathology*; D016000:Cluster Analysis; D060825:Cognitive Dysfunction / Q000145:classification* / Q000473:pathology*; D018728:Entorhinal Cortex / Q000473:pathology; D005240:Feasibility Studies; D005260:Female; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008569:Memory Disorders / Q000145:classification / Q000473:pathology; D008875:Middle Aged; D009483:Neuropsychological Tests; D012720:Severity of Illness Index; D013702:Temporal Lobe / Q000473:pathology