Single Photon Emission Computed Tomography (SPECT) Imaging Study to Develop a Biomarker for Alzheimer's Disease

The adaptation of imaging agents like 123-I MNI-388 and 123-I MNI-390 as biomarkers of β-amyloid deposition in AD patients for assessing disease requires human validation studies. The purpose of this study is to develop and characterize 123-I MNI-388 and 123-I MNI-390 as objective biomarkers in AD. The significance of this work lies in applying state-of-art quantitative neuroimaging tools to develop a relevant biomarker in living AD patients. In this context we propose to investigate the feasibility of applying this technique as an imaging biomarker of disease in AD patients. Informed consent will be obtained for all subjects. All subjects will undergo a screening evaluation including baseline clinical laboratory testing, a baseline physical and neurological evaluation and baseline cognitive evaluations. Subjects will be given a bolus injection of 123-I MNI-388 and MNI 390 in an antecubital vein. Subjects will undergo serial SPECT imaging scans and serial venous plasma sampling for measurement of 123-I MNI-388 and MNI 390 in plasma (both protein bound and free) over a period of up to 8 hours. The quantitative and visual imaging analyses will be performed by an image-processing specialist who will remain blinded to any clinical information.including diagnosis. The primary imaging outcome measure will be the brain regional distribution volumes expressed as a brain tissue to plasma ratio of the radioligand, 123-I MNI-388 and MNI-390. Time to the peak uptake and amplitude of the peak uptake will be evaluated for all brain regions and the results for the AD patients and controls will be compared.