Madar Igal, Ravert Hayden, Dipaula Antony, Du Yong, Dannals Robert F, Becker Lewis
Division of Nuclear Medicine, The Russell H. Morgan Department of Radiology, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
J Nucl Med. 2007 Jun;48(6):1021-30. doi: 10.2967/jnumed.106.038778. Epub 2007 May 15.
Myocardial perfusion imaging plays an important role in clinical management of coronary artery disease, but the most commonly used radionuclides significantly underestimate the severity of coronary artery stenosis. The objective of this study was to evaluate the potential clinical utility of the PET compound (18)F-fluorobenzyl triphenyl phosphonium ((18)F-FBnTP) and characterize its capacity to assess the severity of coronary artery stenosis in a canine model in vivo and ex vivo.
(18)F-FBnTP myocardial uptake was measured in 17 dogs with various degrees of stenosis of the left anterior descending (LAD) or circumflex (LCx) coronary arteries during adenosine vasodilation, using dynamic PET and gamma-well counting. True myocardial blood flow in ischemic (IS) and nonischemic (NIS) beds of the left ventricle was determined with radioactive microspheres. (18)F-FBnTP and (99m)Tc-tetrofosmin activities were compared in 8 dogs ex vivo.
The quantitative assessment of the perfusion defect was significantly (P < 0.03) more accurate with (18)F-FBnTP than with (99m)Tc-tetrofosmin, in mild (IS/NIS; 0.72 +/- 0.08, 0.93 +/- 0.07, respectively, mean +/- SE) and severe stenosis (0.42 +/- 0.05, 0.64 +/- 0.08, respectively), compared with microsphere flow (mild, 0.43 +/- 0.06; severe, 0.22 +/- 0.04). The IS/NIS ratio of both radionuclides correlated linearly with microsphere flow disparity with a similar slope. Flow defect contrast was 2.7 times greater for (18)F-FBnTP than for (99m)Tc-tetrofosmin, as inferred from the regression line intercept (0.14 vs. 0.38, respectively). The (18)F-FBnTP PET IS/NIS ratio (mild, 0.70 +/- 0.04; severe, 0.46 +/- 0.02), did not differ statistically (P >or= 0.330) from that measured ex vivo. A nearly identical qualitative and quantitative estimate of stenosis severity was obtained by early, short (5-15-min) and delayed, prolonged (30-60-min) (18)F-FBnTP PET scans. The stenotic area measured by PET was 16% smaller than that defined by tissue staining.
(18)F-FBnTP PET is a promising new technology for rapid noninvasive detection and assessment of perfusion defect severity in the myocardium.
心肌灌注成像在冠状动脉疾病的临床管理中发挥着重要作用，但最常用的放射性核素会显著低估冠状动脉狭窄的严重程度。本研究的目的是评估正电子发射断层显像（PET）化合物（18）F-氟苄基三苯基鏻（（18）F-FBnTP）的潜在临床效用，并在犬体内和体外模型中表征其评估冠状动脉狭窄严重程度的能力。
在腺苷血管扩张期间，使用动态PET和γ井计数法，测量了17只左前降支（LAD）或回旋支（LCx）冠状动脉有不同程度狭窄的犬的（18）F-FBnTP心肌摄取量。用放射性微球测定左心室缺血（IS）和非缺血（NIS）区域的真实心肌血流量。在8只犬体外比较了（18）F-FBnTP和（99m）锝-替曲膦的活性。
在轻度（IS/NIS；分别为0.72±0.08、0.93±0.07，平均值±标准误）和重度狭窄（分别为0.42±0.05、0.64±0.08）时，与微球血流（轻度，0.43±0.06；重度，0.22±0.04）相比，（18）F-FBnTP对灌注缺损的定量评估比（99m）锝-替曲膦更准确（P<0.03）。两种放射性核素的IS/NIS比值与微球血流差异呈线性相关，斜率相似。从回归线截距推断，（18）F-FBnTP的血流缺损对比度比（99m）锝-替曲膦大2.7倍（分别为0.14和0.38）。（18）F-FBnTP PET的IS/NIS比值（轻度，0.70±0.04；重度，0.46±0.02）与体外测量值无统计学差异（P≥0.330）。通过早期、短时间（5 - 15分钟）和延迟、长时间（30 - 60分钟）的（18）F-FBnTP PET扫描，对狭窄严重程度获得了几乎相同的定性和定量估计。PET测量的狭窄面积比组织染色定义的面积小16%。
（18）F-FBnTP PET是一种有前景的新技术，可用于快速无创检测和评估心肌灌注缺损的严重程度。
