Helen Wills Neuroscience Institute, University of California, Berkeley, 118 Barker Hall MC #3190, Berkeley, CA, 94720-3190, USA,
Eur J Nucl Med Mol Imaging. 2014 Jul;41(7):1398-407. doi: 10.1007/s00259-014-2753-3. Epub 2014 Mar 20.
The increasing use of amyloid PET in Alzheimer's disease research and clinical trials has motivated efforts to standardize methodology. We compared retention of the (11)C radiotracer Pittsburgh Compound B (PiB) and that of two (18)F amyloid radiotracers (florbetapir and flutemetamol) using two study populations. We also examined the feasibility of converting between tracer-specific measures, using PiB as the common link between the two (18)F tracers.
One group of 40 subjects underwent PiB and flutemetamol imaging sessions and a separate group of 32 subjects underwent PiB and florbetapir imaging sessions. We compared cortical and white matter retention for each (18)F tracer relative to that of PiB, as well as retention in several reference regions and image analysis methods. Correlations between tracer pairs were used to convert tracer-specific threshold values for amyloid positivity between tracers.
Cortical retention for each pair of tracers was strongly correlated regardless of reference region (PiB-flutemetamol, ρ = 0.84-0.99; PiB-florbetapir, ρ = 0.83-0.97) and analysis method (ρ = 0.90-0.99). Compared to PiB, flutemetamol had higher white matter retention, while florbetapir had lower cortical retention. Two previously established independent thresholds for amyloid positivity were highly consistent when values were converted between tracer pairs.
Despite differing white and grey matter retention characteristics, cortical retention for each (18)F tracer was highly correlated with that of PiB, enabling conversion of thresholds across tracer measurement scales with a high level of internal consistency. Standardization of analysis methods and measurement scales may facilitate the comparison of amyloid PET data obtained using different tracers.
由于淀粉样蛋白 PET 在阿尔茨海默病研究和临床试验中的应用日益增多，因此努力促使方法标准化。我们使用两种研究人群比较了（11）C 放射性示踪剂匹兹堡化合物 B（PiB）和两种（18）F 淀粉样蛋白放射性示踪剂（florbetapir 和 flutemetamol）的保留情况。我们还研究了使用 PiB 作为两种（18）F 示踪剂之间的共同联系在示踪剂特异性测量之间转换的可行性。
一组 40 名受试者接受 PiB 和 flutemetamol 成像检查，另一组 32 名受试者接受 PiB 和 florbetapir 成像检查。我们比较了每种（18）F 示踪剂相对于 PiB 的皮质和白质保留情况，以及几个参考区域和图像分析方法的保留情况。示踪剂对之间的相关性用于在示踪剂之间转换示踪剂特异性的淀粉样蛋白阳性的阈值。
无论参考区域（PiB-flutemetamol，ρ=0.84-0.99；PiB-florbetapir，ρ=0.83-0.97）和分析方法（ρ=0.90-0.99）如何，每对示踪剂的皮质保留都高度相关。与 PiB 相比，flutemetamol 的白质保留更高，而 florbetapir 的皮质保留更低。当在示踪剂对之间转换值时，两种先前建立的独立淀粉样蛋白阳性阈值高度一致。
尽管存在不同的白质和灰质保留特征，但每种（18）F 示踪剂的皮质保留与 PiB 高度相关，能够在示踪剂测量尺度之间转换阈值，具有高度的内部一致性。分析方法和测量尺度的标准化可能有助于比较使用不同示踪剂获得的淀粉样蛋白 PET 数据。
