DaTscan Findings in Patients with Mild Cognitive Impairment, Alzheimer's Disease and Dementia with Lewy Bodies (IN3-1.008)

OBJECTIVE: To compare the findings on DaTscan between patients with mild cognitive impairment (MCI), Alzheimer9s disease (AD) and dementia with Lewy bodies (DLB). BACKGROUND: Reduced striatonigral uptake on DaTscan reflects dopamine deficiency, and this finding is typical of DLB. One would predict that MCI patients with negligible parkinsonism but who have other features suggesting underlying Lewy body disease (LBD) pathology [eg, REM sleep behavior disorder or (RBD) and/or nonamnestic MCI (naMCI)] will have reduced striatonigral uptake compared to those with AD or amnestic MCI (aMCI), but uptake in AD and MCI will be greater than in DLB. DESIGN/METHODS: DaTscan imaging was performed 3-6 hours after injection of 3-5 mCI of 123 I Ioflupane (DaTscan). ROIs were placed over the right and left putamen of each subject. Identical ROIs were placed over ipsilateral occipital cortical tissue. The means of the right and left putamen to occipital ratios (mPOR) of uptake for each patient were analyzed. RESULTS: 25 subjects (mean age 71 years, 23 male) have undergone DaTscan. UPDRS scores are higher in DLB compared to MCI and AD. The mPOR ± SD for each syndrome is MCI (n=8): 2.00 ± 0.53 [aMCI (n=3): 2.33 ± 0.24, naMCI (n=5): 1.80 ± 0.57], AD (n=5): 2.59 ± 0.57, and DLB (n=12): 1.27 ± 0.27. All naMCI and DLB subjects and 1 aMCI had RBD. Using a mPOR of 2.1, all RBD cases but 1 had values CONCLUSIONS: As predicted, the striatonigral uptake is lowest in DLB and highest in AD. Uptake in those with naMCI and/or RBD is more similar to DLB while those with aMCI and/or absence of RBD is more similar to AD. Further work in much larger numbers of MCI subjects (with an adequate number of females) will determine the potential utility of DaTscan in differentiating underlying LBD from AD in those with MCI. Supported by: GE Healthcare, NIA grants P50 AG016574 and RO1 AG015866, the Mangurian Foundation, and the Robert H. and Clarice Smith and Abigail Van Buren Alzheimer9s Disease Research Program of the Mayo Foundation. Disclosure: Dr. Boeve has received research support from Cephalon, Inc.; Allon Therapeutics; and GE Healthcare. Dr. Lowe received personal compensation for consulting from Bayer Pharmaceuticals. Dr. Lowe received research grants from GE Health Care, Siemens Molecular Imaging, and AVID Radiopharmaceuticals, Inc. Dr. Kantarci has received compensation from Takeda Global Research & Development Center for serving as an advisory board member for research support. Dr. Ferman has nothing to disclose. Dr. Silber has nothing to disclose. Dr. St. Louis has receieved personal compensation for activities with Inspire, Inc. for serving as a member of Adverse Events Adjudication Committee. Dr. Smith has nothing to disclose. Dr. Ivnik has nothing to disclose. Dr. Knopman has received personal compensation for activities with Eli Lilly & Company. Dr. Knopman has received personal compensation in an editorial capacity for Neurology. Dr. Knopman has received research support from TauRx. Dr. Jack has received personal compensation for activities with Janssen, Eisai Inc., General Electric, Johnson & Johnson, and Eli Lilly & Company. Dr. Jack has received research support from Pfizer Inc, Allon, and Baxter. Dr. Jack has received research support from Allon and Baxter. Dr. Petersen has received personal compensation for activities with Pfizer, Inc., Janssen Alzheimer9s Immunotherapy, Elan Pharmaceuticals, GE Healthcare, and Novartis.