RT Journal Article
SR Electronic
T1 Biomarker based prediction of progression to dementia: F18-FDG PET in amnestic-MCI.
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1665
OP 1665
VO 59
IS supplement 1
A1 Madhavi Tripathi
A1 Manjari Tripathi
A1 Girish Parida
A1 Nishikant Damle
A1 Rajeev Kumar
A1 Chandrasekhar Bal
YR 2018
UL http://jnm.snmjournals.org/content/59/supplement_1/1665.abstract
AB 1665Background: Metabolic patterns on brain F-18 FDG PET can potentially predict the decline of aMCI to Alzheimers disease dementia (AD) or other dementias. Objectives: To determine the diagnostic accuracy of the F-18 FDG PET index test for detecting people with aMCI at baseline who would clinically convert to Alzheimer’s disease dementia or other forms of dementia at follow-up. Methods: This was a delayed verification cross-sectional study in which a total 87 patients with aMCI patients underwent clinical and neuropsychological examination, MRI and FDG-PET at baseline. The cases were visually classified into predefined dementia patterns by two nuclear medicine physicians. Automated analysis of FDG PET was also performed using Cortex ID (GE Healthcare). All included patients were divided into two groups, the MCI converters (MCI-C) and MCI non-converters (MCI-NC) based on the neurologists and neuropsychological evaluation at the end of follow-up. Senitivity, specificity and accuracy of FDG-PET was computed. Results: The mean age of included subjects 66.6+9.1 years, range 48 to 82 years, M:F ratio was 2.1 : 1 (59:28) and MMSE scores were 26.8 + 1.8 (range 24 to 29). Mean final follow-up was at 30.4 + 9.3 months (range:18 months to 48 months) with one death due to unrelated cause. There were 23 MCI-C and 64 MCI-NC. Of the 23 MCI-C, 19 were diagnosed as probable AD, 1 as frontotemporal dementia and 3 as vascular dementia. The conversion rate for all-types of dementia in our series was 26.4 % (23/87) and for Alzheimers type dementia it was 21.8 % (19/87). There were 23 patients with of unilateral or bilateral parieto-temporal, including posterior cingulate and precuneus hypometabolism that was taken as a pattern suggestive of progression to AD on FDG PET. Both visual and voxel-based cortex id were used for defining this pattern. The sensitivity and specificity of FDG PET visual assesment for a diagnosis of all types of dementias was 86.9 (66.4 -97.2 %) and 93.7 % (84.7-98.2 %) and for AD it was 100 % (82.3-100.0 %) and 94.1 % (85.6-98.7%). Significantly lower cortical glucose metabolism was found in MCI-C relative to MCI-NC in the AD-related regions on Cortex ID. There were 3 patients with marked cerebral atrophy on CT and FDG uptake was commensurate with atrophy, all three patients were subsequently diagnosed as vascular dementia. 28 patients (32 %) had hypometabolism in unilateral parietal (3), temporal (6), frontal (1), occipital (1) or bilateral parietal (1), temporal (13), parieto-occipital (1) and insular (2) l cortices. Commonest being bilateral followed by unilateral temporal hypometabolism-none of these patients had progression in cognitive decline however. Conclusions: Hypometabolism in the posterior cingulate & precuneus in addition to parieto-temporal cortices is a reliable indicator for progression to AD. Marked cerebral atrophy may be a potential marker for VD. Unilateral or even bilateral temporal hypometabolism may not suggest progression to AD.