Lautamäki Riikka, George Richard T, Kitagawa Kakuya, Higuchi Takahiro, Merrill Jennifer, Voicu Corina, DiPaula Anthony, Nekolla Stephan G, Lima João A C, Lardo Albert C, Bengel Frank M
Department of Radiology, Division of Nuclear Medicine, Johns Hopkins Medical Institutions, Baltimore, MD 21210, USA.
Eur J Nucl Med Mol Imaging. 2009 Apr;36(4):576-86. doi: 10.1007/s00259-008-0972-1. Epub 2008 Nov 5.
Absolute quantification of myocardial blood flow expands the diagnostic potential of PET for assessment of coronary artery disease. (82)Rb has significantly contributed to increasing utilization of PET; however, clinical studies are still mostly analysed qualitatively. The aim of this study was to reevaluate the feasibility of (82)Rb for flow quantification, using hybrid PET-CT in an animal model of coronary stenosis.
Nine dogs were prepared with experimental coronary artery stenosis. Dynamic PET was performed for 8 min after (82)Rb(1480-1850 MBq) injection during adenosine-induced vasodilation. Microspheres were injected simultaneously for reference flow measurements. CT angiography was used to determine the myocardial regions related to the stenotic vessel. Two methods for flow calculation were employed: a two-compartment model including a spill-over term, and a simplified retention index.
The two-compartment model data were in good agreement with microsphere flow (y = 0.84x + 0.20; r = 0.92, p<0.0001), although there was variability in the physiological flow range <3 ml/g per minute (y = 0.54x + 0.53; r = 0.53, p = 0.042). Results from the retention index also correlated well with microsphere flow (y = 0.47x + 0.52; r = 0.75, p = 0.0004). Error increased with higher flow, but the correlation was good in the physiological range (y = 0.62x + 0.29; r = 0.84, p = 0.0001).
Using current state-of-the-art PET-CT systems, quantification of myocardial blood flow is feasible with (82)Rb. A simplified approach based on tracer retention is practicable in the physiological flow range. These results encourage further testing of the robustness and usefulness in the clinical context of cardiac hybrid imaging.
心肌血流量的绝对定量扩展了PET在评估冠状动脉疾病方面的诊断潜力。（82）铷对PET应用的增加有显著贡献；然而，临床研究大多仍采用定性分析。本研究的目的是在冠状动脉狭窄动物模型中，使用PET-CT混合成像重新评估（82）铷进行血流量定量的可行性。
对9只犬制备实验性冠状动脉狭窄。在腺苷诱导血管扩张期间，注射（82）铷（1480 - 1850 MBq）后进行8分钟的动态PET检查。同时注射微球用于参考血流量测量。CT血管造影用于确定与狭窄血管相关的心肌区域。采用两种血流量计算方法：一种包含溢出项的双室模型，以及一种简化的滞留指数。
双室模型数据与微球血流量高度一致（y = 0.84x + 0.20；r = 0.92，p<0.0001），尽管在生理血流量范围<3 ml/g每分钟时存在变异性（y = 0.54x + 0.53；r = 0.53，p = 0.042）。滞留指数的结果也与微球血流量具有良好的相关性（y = 0.47x + 0.52；r = 0.75，p = 0.0004）。误差随血流量增加而增大，但在生理范围内相关性良好（y = 0.62x + 0.29；r = 0.84，p = 0.0001）。
使用当前最先进的PET-CT系统，用（82）铷进行心肌血流量定量是可行的。基于示踪剂滞留的简化方法在生理血流量范围内是可行的。这些结果鼓励在心脏混合成像的临床环境中进一步测试其稳健性和实用性。
