Automated mapping of hippocampal atrophy in 1-year repeat MRI data from 490 subjects with Alzheimer's disease, mild cognitive impairment, and elderly controls.
As one of the earliest structures to degenerate in Alzheimer's disease (AD), the hippocampus is the target of many studies of factors that influence rates of brain degeneration in the elderly. In one of the largest brain mapping studies to date, we mapped the 3D profile of hippocampal degeneration over time in 490 subjects scanned twice with brain MRI over a 1-year interval (980 scans). We examined baseline and 1-year follow-up scans of 97 AD subjects (49 males/48 females), 148 healthy control subjects (75 males/73 females), and 245 subjects with mild cognitive impairment (MCI; 160 males/85 females). We used our previously validated automated segmentation method, based on AdaBoost, to create 3D hippocampal surface models in all 980 scans. Hippocampal volume loss rates increased with worsening diagnosis (normal=0.66%/year; MCI=3.12%/year; AD=5.59%/year), and correlated with both baseline and interval changes in Mini-Mental State Examination (MMSE) scores and global and sum-of-boxes Clinical Dementia Rating scale (CDR) scores. Surface-based statistical maps visualized a selective profile of ongoing atrophy in all three diagnostic groups. Healthy controls carrying the ApoE4 gene atrophied faster than non-carriers, while more educated controls atrophied more slowly; converters from MCI to AD showed faster atrophy than non-converters. Hippocampal loss rates can be rapidly mapped, and they track cognitive decline closely enough to be used as surrogate markers of Alzheimer's disease in drug trials. They also reveal genetically greater atrophy in cognitively intact subjects.
Morra
Jonathan H
JH
Laboratory of Neuro Imaging, Dept. of Neurology, UCLA School of Medicine, Neuroscience Research Building 225E, 635 Charles Young Drive, Los Angeles, CA 90095-1769, USA.
Tu
Zhuowen
Z
Apostolova
Liana G
LG
Green
Amity E
AE
Avedissian
Christina
C
Madsen
Sarah K
SK
Parikshak
Neelroop
N
Toga
Arthur W
AW
Jack
Clifford R
CR
Schuff
Norbert
N
Weiner
Michael W
MW
Thompson
Paul M
PM
D000368:Aged; D000465:Algorithms; D000544:Alzheimer Disease / Q000235:genetics / Q000473:pathology*; D053327:Apolipoprotein E4 / Q000235:genetics; D001284:Atrophy; D001331:Automation; D001931:Brain Mapping / Q000379:methods*; D003072:Cognition Disorders / Q000235:genetics / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male
D053327:Apolipoprotein E4