Kaufmann P A, Gnecchi-Ruscone T, Yap J T, Rimoldi O, Camici P G
Medical Research Council Cyclotron Unit, Imperial College School of Medicine, Hammersmith Hospital, London, United Kingdom.
J Nucl Med. 1999 Nov;40(11):1848-56.
PET with 15O-labeled water allows noninvasive quantification of myocardial blood flow (MBF) at baseline and during pharmacologically induced hyperemia to assess the coronary vasodilator reserve (CVR = hyperemic/baseline MBF). Despite widespread use of PET, its reproducibility during one study session has not been tested. Intravenous adenosine (Ado), a powerful coronary vasodilator with a very short decay time, is commonly used for the induction of hyperemia. However, it is not known whether Ado can induce tachyphylaxis after short-term repetitive administration. In this study, we aimed to test the reproducibility of PET assessment of CVR during Ado-induced hyperemia.
In 21 healthy volunteer men, baseline and Ado MBF were measured twice using PET with 15O-labeled water to obtain two CVR assessments within 1 h.
There was no significant difference between the two baselines (0.89 +/- 0.14 versus 0.99 +/- 0.15 mL/min/g, mean difference 13% +/- 11%) or between the two hyperemic MBFs (3.51 +/- 0.45 versus 3.83 +/- 0.49 mL/min/g, mean difference 10% +/- 14%), resulting in comparable values of CVR (4.05 +/- 0.75 versus 3.93 +/- 0.72, mean difference 2% +/- 15%). The repeatability coefficient for MBF was 0.17 mL/min/g at baseline and 0.94 mL/min/g during hyperemia. The repeatability coefficient of the rate pressure product (RPP) was lower at baseline (1,304 mm Hg x beat/min) than during hyperemia (3,448 mm Hg x beat/min).
Repeated measurements of MBF and CVR during the same study session were not significantly different, demonstrating the validity of the technique. The larger variability of hyperemic flow, as indicated by the larger repeatability coefficient, was paralleled by a greater variability of the RPP. This could mean that the greater variability of MBF during stress is more likely due to a variable response to Ado rather than to a measurement error.
使用(^{15}O)标记水的正电子发射断层扫描（PET）可在基线状态及药物诱导充血期间对心肌血流量（MBF）进行无创定量，以评估冠状动脉扩张储备（CVR = 充血期MBF/基线期MBF）。尽管PET已广泛应用，但其在一次研究过程中的可重复性尚未得到检验。静脉注射腺苷（Ado）是一种强效冠状动脉扩张剂，半衰期很短，常用于诱导充血。然而，尚不清楚短期重复给药后Ado是否会引起快速耐受性。在本研究中，我们旨在检验PET评估Ado诱导充血期间CVR的可重复性。
在21名健康男性志愿者中，使用(^{15}O)标记水的PET两次测量基线期和Ado诱导充血期的MBF，以在1小时内获得两次CVR评估值。
两次基线期MBF之间（分别为0.89±0.14与0.99±0.15 mL/min/g，平均差异13%±11%）或两次充血期MBF之间（分别为3.51±0.45与3.83±0.49 mL/min/g，平均差异10%±14%）均无显著差异，导致CVR值相当（分别为4.05±0.75与3.93±0.72，平均差异2%±15%）。MBF的重复性系数在基线期为0.17 mL/min/g，充血期为0.94 mL/min/g。心率血压乘积（RPP）的重复性系数在基线期（1304 mmHg×次/分钟）低于充血期（3448 mmHg×次/分钟）。
在同一研究过程中对MBF和CVR进行重复测量无显著差异，证明了该技术的有效性。如重复性系数较大所示，充血期血流量变异性更大，同时RPP变异性也更大。这可能意味着应激期间MBF变异性更大更可能是由于对Ado的反应可变，而非测量误差所致。
