The effect of different regions of interest on the quantitative evaluation in amyloid PET images.

1814 Purpose: The quantitative analysis of amyloid positron emission tomography (PET) images can be used to determine the amyloid β (Aβ) deposition in the cerebral cortex, which is used for the diagnosis of Alzheimer’s disease (AD). However, the appropriate regions of interest (ROIs) and reference area on the images must be assessed in order to calculate the quantitative values. These values depend on the setting methods of the ROIs. The purpose of this study was to examine the effect of different ROIs on the quantitative evaluation in amyloid PET images. Methods: One hundred and sixty-six patients including 58 normal controls (NCs), 62 cases of mild cognitive impairment (MCI), and 46 cases of early AD were retrospectively investigated. They underwent amyloid PET at Japanese Alzheimer’s disease neuroimaging initiative (J-ADNI). Clinical data were obtained by the National Bioscience Database Center (NBDC). ROIs were placed using an Automatic-anatomic-labeling region of interest (AAL-ROI) based on the anatomical brain region and an Empirically PiB-prone ROI (EPP-ROI) specialized for Aβ deposition. We evaluated the mean cortical standardized uptake value ratio (mcSUVR), which was calculated by averaging the five ROIs (posterior cingulate gyrus and precuneus, frontal lobe, temporal lobe lateral side, parietal lobe lateral side, occipital lobe). The reference region was the cerebellar cortex. Results: The mcSUVR of NCs, MCI and AD were 1.39±0.34, 1.82±0.50, and 2.11±0.47 for EPP-ROI and 1.24±0.27, 1.56±0.38, and 1.78±0.37 for AAL-ROI, respectively. Significant differences were observed among these groups (P<0.05). The mcSUVR of EPP-ROI was significantly higher than that of AAL-ROI by 11.6%±3.47%, 15.5%±4.51%, and 18.2±3.09% for NCs, MCI and AD, respectively. In addition, the mcSUVR of EPP-ROI was higher than that of AAL-ROI by 10.3%±2.53%, 13.2%±2.55%, and 18.7±1.92% for negative, equivocal and positive, respectively. Conclusions: This study suggested that the ROI influenced the quantitative values. The EPP-ROI result in higher SUVR values than the AAL-ROI between negative and positive. These results implied that the EPP-ROI can distinguish disease rather than AAL-ROI.