RT Journal Article
SR Electronic
T1 Longitudinal Magnetization Transfer Imaging in Mild to Severe Alzheimer Disease
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
DO 10.3174/ajnr.A2812
A1 S. Ropele
A1 R. Schmidt
A1 C. Enzinger
A1 M. Windisch
A1 N.P. Martinez
A1 F. Fazekas
YR 2011
UL http://www.ajnr.org/content/early/2011/12/15/ajnr.A2812.abstract
AB BACKGROUND AND PURPOSE: MTI has been proposed as a sensitive technique for studying microstructural brain tissue changes in patients with AD, but the course of these changes over time is largely unknown. We therefore used a placebo-controlled study of memantine to follow the evolution of tissue damage in AD by means of MTR measurements and investigated how MTR changes were related to brain atrophy and cognition. MATERIALS AND METHODS: Twenty-eight patients (76.5 ± 5.8 years) with mild to moderate AD underwent MTI, brain volume measurements, and cognitive testing at baseline and after 6 and 12 months. Nineteen healthy individuals (73.3 ± 3.2 years) served as controls. MTI was performed with a 2-minute protocol that was optimized for an enhanced MT effect and reduced motion sensitivity. Global and regional MTR measurements served as correlations with brain volumes and the MMSE score. RESULTS: AD patients had significantly lower global MTR values than controls, and showed a consistent and significant MTR reduction in all regions investigated over a period of 12 months. These MTR changes were paralleled by a brain tissue loss of 2.2% per year. Associations between MTR and cognition were found for the hippocampus, putamen, and thalamus, and were more pronounced in the left hemisphere. CONCLUSIONS: MTI in AD allows the assessment of ongoing global and regional brain damage independent of atrophy, and therefore appears to be a valuable marker for disease-related tissue changes. Abbreviations ADAlzheimer diseaseFMRIBfunctional MR imaging of the brainMMSEMini-Mental State ExaminationMPRAGEmagnetization-prepared rapid acquisition of gradient echoMTmagnetization transferMTImagnetization transfer imagingMTRmagnetization transfer ratioSARspecific absorption rate