Department of Radiology, Rochester, Minnesota;
Department of Radiology, Rochester, Minnesota.
J Nucl Med. 2022 Nov;63(11):1748-1753. doi: 10.2967/jnumed.121.263136. Epub 2022 Mar 17.
In tau PET, a reliable method to detect early tau accumulation in the brain is crucial. Noise, artifacts, and off-target uptake impede detection of subtle true-positive ligand binding. We hypothesize that identifying voxels with stable activity over time can enhance detection of true-positive tau. In total, 339 participants in the clinical spectrum ranging from clinically unimpaired to Alzheimer disease dementia underwent at least 2 serial tau PET scans with flortaucipir. The overlap index (OI) method was proposed to detect spatially identical, voxelwise SUV ratio (SUVR) elevation when seen sequentially in serial tau PET scans. The association of OI with tau accumulation, clinical diagnosis, and cognitive findings was evaluated. OI showed good dynamic range in the low-SUVR window. Only OI was able to identify subgroups with increasing tau PET signal in low-SUVR meta-region-of-interest (ROI) groups. OI showed improved association with early clinical disease progression and cognitive scores versus meta-ROI SUVR measures. OI was more sensitive to tau signal elevation and longitudinal change than standard ROI measures, suggesting it is a more sensitive method for detecting early, subtle deposition of neurofibrillary tangles.
在 tau PET 中，可靠的方法来检测大脑中早期 tau 的积累至关重要。噪声、伪影和非靶标摄取会阻碍对微妙的真正阳性配体结合的检测。我们假设，确定随时间稳定活动的体素可以增强对真正阳性 tau 的检测。共有 339 名参与者在临床范围内，从临床无症状到阿尔茨海默病痴呆，接受了至少 2 次 flortaucipir 的 tau PET 扫描。提出了重叠指数 (OI) 方法来检测当在连续 tau PET 扫描中依次看到时空间相同的体素 SUV 比 (SUVR) 升高。评估了 OI 与 tau 积累、临床诊断和认知发现的相关性。OI 在低 SUVR 窗口中显示出良好的动态范围。只有 OI 能够识别在低 SUVR 元感兴趣区 (ROI) 组中tau PET 信号增加的亚组。与 meta-ROI SUVR 测量相比，OI 与早期临床疾病进展和认知评分的相关性更好。OI 比标准 ROI 测量更能敏感地检测到 tau 信号的升高和纵向变化，表明它是一种更敏感的方法，用于检测早期、微妙的神经纤维缠结沉积。
