Duara R, Loewenstein DA, Shen Q, Barker W, Potter E, Varon D, Heurling K, Vandenberghe R, Buckley C.
[18F]flutemetamol PET imaging and medial temporal atrophy measures in distinguishing aMCI and AD from elderly normals.
Human Amyloid Imaging 2011 Meeting Abstracts. 2011 Jan 15;
Objective: To evaluate the individual and combined contributions of [18F]flutemetamol-labeled amyloid PET and
volumetrically-acquired MRI measures for diagnostic classification.
Methods: We studied 10 young normals (yo-NCI) (38.9 yr), 15 elderly normals (el-NCI) (70.8 yr), 20 amnestic MCI
(aMCI) (72.1 yr) and 27 AD (71.1 yr) subjects. A mean cortical SUVR of 1.56+ was used to classify subjects as
Amyloid positive (Am+ve). Hippocampal (HP) volumes and a visual rating system (VRS) were used to rate HP and
entorhinal cortex atrophy on MRI scans, using a mean VRS score of 1.75+ to classify subjects as MRI positive
Results: VRS and HP volumes were equivalent for classifying aMCI and AD. The rates of MRI+ve scans among
yo-NCI, el-NCI, aMCI and AD subjects was: 0%, 7%, 70% and 75%, respectively. The rates of Am+ve scans for
these same groups of subjects was: 0%, 7%, 50% and 93%, respectively. The rates of either Am+ve or MRI+ve
scan for these subject groups was: 0%, 13%, 85% and 96%, respectively. Among all MRI+ve subjects, 83% were
Am+ve, but among all Am+ve subjects, 43% were MRI-ve, suggesting that amyloid deposition leads structural
changes. Only 2/27 AD subjects were Am-ve, one of which was MRI+ve. However, 10/20 aMCI were Am+ve, of
which 7/10 were MRI+ve and 7/10 Am-ve aMCI subjects were also MRI+ve. By logistic regression this represented
a significant added value of MRI in combination with flutemetamol-PET in the classification of aMCI versus el-NCI.
Conclusions: [18F]flutemetamol PET and structural MRI provided additive information in the diagnostic classification
of cognitvely impaired subjects. This was most evident among Am-ve aMCI subjects, 70% of whom were MRI+ve,
suggesting a substantitive non-AD neurodegenerative etiology among aMCI subjects in this sample.