Avid Radiopharmaceuticals, Philadelphia, PA, USA.
Departments of Neurology and Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Alzheimers Dement. 2018 Dec;14(12):1565-1571. doi: 10.1016/j.jalz.2018.06.1353. Epub 2018 Jul 11.
Klunk et al. recently proposed a means of standardizing quantitation of amyloid burden from positron emission tomography scans to a common Centiloid scale, and we have applied that method to florbetapir.
Florbetapir and Pittsburgh compound B scans were acquired for 46 mixed clinical presentation subjects within 18 ± 20 days. Florbetapir and Pittsburgh compound B cortical standardized uptake value ratio (SUVr) values were well correlated for both standard Centiloid (R = 0.894) and Avid (R = 0.901) volume of interests (VOIs). The methods of Klunk et al. were applied to establish a conversion first from florbetapir SUVr values obtained using standard Centiloid VOIs to Centiloids and then from Avid VOIs (Joshi et al.) to Centiloids.
The equation for conversion of florbetapir SUVr from Avid VOIs to the Centiloid scale was as follows: Florbetapir Centiloids = 183 × SUVr - 177. The threshold that discriminated neuropathologically verified none or sparse versus moderate to frequent plaques in autopsy-confirmed data is 24.1 Centiloids.
These findings may allow improved tracer-independent amyloid quantitation.
Klunk 等人最近提出了一种标准化正电子发射断层扫描（PET）扫描中淀粉样蛋白负担定量的方法，将其转化为常见的百分位标度，并将该方法应用于 florbetapir。
在 18±20 天内，对 46 名混合临床表现的患者进行了 florbetapir 和匹兹堡化合物 B 扫描。对于标准 Centiloid（R=0.894）和 Avid（R=0.901）体积感兴趣区（VOI），florbetapir 和匹兹堡化合物 B 皮质标准化摄取值比（SUVr）值均具有良好的相关性。Klunk 等人的方法被应用于建立从使用标准 Centiloid VOI 的 florbetapir SUVr 值到 Centiloids 的转换，然后从 Avid VOI（Joshi 等人）到 Centiloids 的转换。
从 Avid VOI 将 florbetapir SUVr 转换为百分位标度的方程如下：florbetapir Centiloids=183×SUVr-177。在尸检证实数据中，区分神经病理学证实无或稀疏斑块与中度至频繁斑块的阈值为 24.1 Centiloids。
这些发现可能允许改进与示踪剂无关的淀粉样蛋白定量。
