Comparing 3 T and 1.5 T MRI for tracking Alzheimer's disease progression with tensor-based morphometry.
A key question in designing MRI-based clinical trials is how the main magnetic field strength of the scanner affects the power to detect disease effects. In 110 subjects scanned longitudinally at both 3.0 and 1.5 T, including 24 patients with Alzheimer's Disease (AD) [74.8 +/- 9.2 years, MMSE: 22.6 +/- 2.0 at baseline], 51 individuals with mild cognitive impairment (MCI) [74.1 +/- 8.0 years, MMSE: 26.6 +/- 2.0], and 35 controls [75.9 +/- 4.6 years, MMSE: 29.3 +/- 0.8], we assessed whether higher-field MR imaging offers higher or lower power to detect longitudinal changes in the brain, using tensor-based morphometry (TBM) to reveal the location of progressive atrophy. As expected, at both field strengths, progressive atrophy was widespread in AD and more spatially restricted in MCI. Power analysis revealed that, to detect a 25% slowing of atrophy (with 80% power), 37 AD and 108 MCI subjects would be needed at 1.5 T versus 49 AD and 166 MCI subjects at 3 T; however, the increased power at 1.5 T was not statistically significant (alpha = 0.05) either for TBM, or for SIENA, a related method for computing volume loss rates. Analysis of cumulative distribution functions and false discovery rates showed that, at both field strengths, temporal lobe atrophy rates were correlated with interval decline in Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog), mini-mental status exam (MMSE), and Clinical Dementia Rating sum-of-boxes (CDR-SB) scores. Overall, 1.5 and 3 T scans did not significantly differ in their power to detect neurodegenerative changes over a year. Hum Brain Mapp, 2010. (c) 2009 Wiley-Liss, Inc.
Laboratory of Neuro Imaging, Department of Neurology, UCLA School of Medicine, Los Angeles, California 90095-1769., USA.
April J
AJ
Ho
Xue
X
Hua
Suh
S
Lee
Alex D
AD
Leow
Igor
I
Yanovsky
Boris
B
Gutman
Ivo D
ID
Dinov
Natasha
N
Leporé
Jason L
JL
Stein
Arthur W
AW
Toga
Clifford R
CR
Jack
Matt A
MA
Bernstein
Eric M
EM
Reiman
Danielle J
DJ
Harvey
John
J
Kornak
Norbert
N
Schuff
Gene E
GE
Alexander
Michael W
MW
Weiner
Paul M
PM
Thompson
D000368:Aged; D000544:Alzheimer Disease / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D003072:Cognition Disorders / Q000473:pathology*; D056324:Diffusion Tensor Imaging / Q000295:instrumentation* / Q000379:methods*; D018450:Disease Progression; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008297:Male; D012720:Severity of Illness Index; D013702:Temporal Lobe / Q000473:pathology; D013997:Time Factors