Srinivasan G, Kitsiou A N, Bacharach S L, Bartlett M L, Miller-Davis C, Dilsizian V
Cardiology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1650, USA.
Circulation. 1998 Mar 10;97(9):843-50. doi: 10.1161/01.cir.97.9.843.
New high-energy collimators for single photon emission computed tomography (SPECT) cameras have made imaging of positron-emitting tracers, such as [18F]fluorodeoxyglucose (18FDG), possible. We examined differences between SPECT and PET technologies and between 18FDG and thallium tracers to determine whether 18FDG SPECT could be adopted for assessment of myocardial viability.
Twenty-eight patients with chronic coronary artery disease (mean left ventricular ejection fraction [LVEF]=33+/-15% at rest) underwent 18FDG SPECT, 18FDG PET, and thallium SPECT studies. Receiver operating characteristic curves showed overall good concordance between SPECT and PET technologies and thallium and 18FDG tracers for assessing viability regardless of the level of 18FDG PET cutoff used (40% to 60%). However, in the subgroup of patients with LVEF< or =25%, at 60% 18FDG PET threshold value, thallium tended to underestimate myocardial viability. In a subgroup of regions with severe asynergy, there were considerably more thallium/18FDG discordances in the inferior wall than elsewhere (73% versus 27%, P<.001), supporting attenuation of thallium as a potential explanation for the discordant observations. When uptake of 18FDG by SPECT and PET was compared in 137 segments exhibiting severely irreversible thallium defects (scarred by thallium), 59 (43%) were viable by 18FDG PET, of which 52 (88%) were also viable by 18FDG SPECT. However, of the 78 segments confirmed to be nonviable by 18FDG PET, 57 (73%) were nonviable by 18FDG SPECT (P<.001).
Although 18FDG SPECT significantly increases the sensitivity for detection of viable myocardium in tissue declared nonviable by thallium (to 88% of the sensitivity achievable by PET), it will occasionally (27% of the time) result in falsely identifying as viable tissue that has been identified as nonviable by both PET and thallium.
用于单光子发射计算机断层扫描（SPECT）相机的新型高能准直器已使对正电子发射示踪剂（如[18F]氟脱氧葡萄糖（18FDG））进行成像成为可能。我们研究了SPECT和PET技术之间以及18FDG与铊示踪剂之间的差异，以确定18FDG SPECT是否可用于评估心肌活力。
28例慢性冠状动脉疾病患者（静息时平均左心室射血分数[LVEF]=33±15%）接受了18FDG SPECT、18FDG PET和铊SPECT检查。受试者操作特征曲线显示，无论使用何种18FDG PET截断水平（40%至60%），SPECT和PET技术以及铊和18FDG示踪剂在评估心肌活力方面总体具有良好的一致性。然而，在LVEF≤25%的患者亚组中，在18FDG PET阈值为60%时，铊倾向于低估心肌活力。在严重运动不协调区域的亚组中，下壁的铊/18FDG不一致情况比其他部位多得多（73%对27%，P<0.001），这支持铊摄取减少是观察到不一致情况的一个潜在解释。当比较137个显示严重不可逆铊缺损（铊瘢痕化）节段的18FDG SPECT和PET摄取情况时，18FDG PET显示59个（43%）节段存活，其中52个（88%）节段通过18FDG SPECT也显示存活。然而，在18FDG PET证实为无活力的78个节段中，57个（73%）节段通过18FDG SPECT也显示无活力（P<0.001）。
尽管18FDG SPECT显著提高了在铊显示为无活力的组织中检测存活心肌的敏感性（达到PET可实现敏感性的88%），但它偶尔（27%的时间）会导致将PET和铊均显示为无活力的组织错误地识别为存活组织。
