Graebe Martin, Borgwardt Lise, Højgaard Liselotte, Sillesen Henrik, Kjaer Andreas
Department of Vascular Surgery, Rigshospitalet, University of Copenhagen, Denmark.
Nucl Med Commun. 2010 Sep;31(9):773-9. doi: 10.1097/MNM.0b013e32833c365e.
Quantification of 18-fluorodeoxyglucose (FDG) uptake in inflamed high-risk carotid atherosclerotic plaques is challenged by the spatial resolution of positron emission tomography (PET) and luminal blood activity. Late acquisition protocols have been used to overcome these challenges to enhance the contrast between the plaque and blood-pool FDG activity. However, for prospective studies the late acquisition is inconvenient for the patient and staff, and most retrospective studies of plaque uptake use data from early acquisition protocols. The objective was to evaluate changes in the quantification methods of FDG uptake in carotid artery plaques between early and late PET scans.
FDG uptake 1 and 3 h after tracer injection was compared in 19 carotid artery plaques. The average plaque maximum standardized uptake value (SUVmax) and a target to background ratio (TBR), using venous blood-pool activity as background, were evaluated at the two time points. These methods have been shown earlier to quantitate the degree of inflammation in late hour scans.
A good individual plaque FDG uptake consistency was found between the two time points for SUVmax, r²=0.86. In contrast, the ratio method did not conserve the results between the two time points: TBR r²=0.34. For both methods, absolute values changed over time. TBR values generally increased as blood pool activity decreased, whereas the individual plaque SUVmax values showed both increases and decreases over time.
Identification of carotid plaque inflammation with PET can be performed 1 h after FDG injection using SUVmax for plaque FDG uptake quantification.
炎症性高危颈动脉粥样硬化斑块中18-氟脱氧葡萄糖（FDG）摄取的定量分析受到正电子发射断层扫描（PET）空间分辨率和管腔内血液活性的挑战。后期采集方案已被用于克服这些挑战，以增强斑块与血池FDG活性之间的对比度。然而，对于前瞻性研究而言，后期采集对患者和工作人员都不方便，并且大多数关于斑块摄取的回顾性研究使用的是早期采集方案的数据。目的是评估早期和晚期PET扫描之间颈动脉斑块中FDG摄取定量方法的变化。
比较了19个颈动脉斑块在注射示踪剂后1小时和3小时的FDG摄取情况。在这两个时间点评估了平均斑块最大标准化摄取值（SUVmax）以及以静脉血池活性为背景的靶本比（TBR）。这些方法先前已被证明可在后期扫描中定量炎症程度。
两个时间点之间，SUVmax的个体斑块FDG摄取一致性良好，r² = 0.86。相比之下，比值法在两个时间点之间的结果不一致：TBR r² = 0.34。对于这两种方法，绝对值均随时间变化。TBR值通常随着血池活性降低而增加，而个体斑块SUVmax值随时间既有增加也有降低。
使用SUVmax对斑块FDG摄取进行定量分析时，FDG注射后1小时即可通过PET识别颈动脉斑块炎症。
