deletions | additions       diff --git a/Longitudinal_structural_MRIs_have_been__.tex b/Longitudinal_structural_MRIs_have_been__.tex  index fed9acc..b07e61c 100644  --- a/Longitudinal_structural_MRIs_have_been__.tex  +++ b/Longitudinal_structural_MRIs_have_been__.tex 
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Cerebral metabolic rate of glucose can be measured by PET scan using the tracer fluorine-18 (F-18) fluorodeoxyglucose (FDG).  In AD, the reductions in cerebral metabolism is well established and is one of the two biomarkers targeting neurodegeneration.  The glucose metabolism measures with FDG-PET scan have been used with good accuracy to distinguish AD from both NCs and other dementias \cite{Mosconi_2007,Ballard_2011}.  FDG-PET has also been used to predict MCI to AD converters with better accuracy than structural MRI \cite{Yuan_2008}.  Longitudinal structural MRIs have been widely used as an imaging biomarker for AD.  At present, brain atrophy is measured from the high-resolution acquisitions with MRI scanners of 1.5T or 3T magnets.  The best established and validated atrophy assessment are based on T1-weighted MRIs \cite{Frisoni2010}.