ADNI-GO: 18F-AV-45 as an imaging bio-marker for Alzheimer’s disease

Objectives Alzheimer’s disease is the most common form of dementia and the need for pathological diagnosis in living subjects is important. Postmortem Alzheimer’s disease can be characterized by accumulation of amyloid plaque in the brain. The purpose of the ADNI-GO study was to evaluate the new radiopharmaceutical 18F-AV-45 (AV45) and its effectiveness as an imaging biomarker for amyloid plaque accumulation in subjects with cognitive impairment that may be attributed to the presence of Alzheimer’s disease.

Methods Four subjects have been enrolled in this study at Northwestern Memorial Hospital thus far. Two of the subjects were identified as having early mild cognitive impairment (eMCI) and two were enrolled as normal controls. Subjects underwent a 18F-FDG (FDG) study and subsequent imaging with AV45. A Siemens BioGraph 40 TruePoint PET/CT scanner was used. PET/CT images were acquired 30 minutes after administration of 5 mCi of FDG and 50 minutes after administration of 9 mCi of AV45. Prior to imaging, patients were positioned, marked and assessed to determine if patient motion occurred. Reconstruction of the images was performed per the ADNI-GO protocol, as defined by the LONI Laboratory. For the purpose of this investigation, reconstructions were performed per the department’s clinical PET brain protocol, reviewed and compared to published AV45 results.

Results The AV45 images of the eMCI subjects were significantly different from normal controls, demonstrating increased accumulation of AV45. When compared to previously published literature, the two eMCI brain images were strikingly similar.

Conclusions As demonstrated in published literature, AV45 is an effective radiopharmaceutical in identifying subjects with eMCI. AV45 accumulation, as a marker for beta-amyloid plaque buildup, was prominently seen in subjects with eMCI. Ideally, these four subjects would continue to be followed in the ADNI 2 protocol, which is designed to image subjects over the next five years