Inglese Eugenio, Leva Lucia, Matheoud Roberta, Sacchetti Gianmauro, Secco Chiara, Gandolfo Patrizia, Brambilla Marco, Sambuceti Gianmario
Nuclear Medicine Department, University of Eastern Piedmont, Azienda Ospedaliera Maggiore della Carità, Novara, Italy, USA.
J Nucl Med. 2007 Oct;48(10):1662-9. doi: 10.2967/jnumed.107.041574. Epub 2007 Sep 14.
Imaging of cardiac (18)F-FDG uptake is used in the diagnostic evaluation of residual viable myocardium. Although, originally, hibernating myocardium was identified by a mismatch between perfusion defect and relatively preserved (18)F-FDG uptake, at present several studies propose that (18)F-FDG distribution can also be used alone for this purpose. Nevertheless, even severe myocardial (18)F-FDG uptake defects are frequently observed in cancer patients without any cardiac disease. The aim of this study was to retrospectively analyze global and regional (18)F-FDG cardiac images of 49 consecutive cancer patients free of cardiac diseases who submitted to 3 PET scans under fasting conditions.
Images were acquired with a high-resolution PET/CT scanner. Three-dimensional regions of interest were drawn on the fused PET/CT images to measure the maximal standardized uptake value of the left ventricular myocardium (SUV(Myo)) as well as the average SUV of the left ventricular blood (SUV(LV)) and of the liver (SUV(Liver)). Analysis of regional myocardial (18)F-FDG uptake was performed on a subsample of 26 patients by an automatic recognition of endocardial and epicardial borders and subdividing the left ventricle in 20 segments. Regional (18)F-FDG distribution was defined as the percentage of SUV(Myo) in each region.
SUV(Myo) as well as SUV(LV) and SUV(Liver) did not change on average throughout the studies. This stability was not caused by a persistent pattern of myocardial (18-)FDG distribution. Rather, it was associated with important variations in both directions over time. Regional (18)F-FDG distribution was largely heterogeneous in all 3 studies, with a variation coefficient in each patient of 18% +/- 7%, 18% +/- 5%, and 17% +/- 5%, respectively. An (18)F-FDG uptake of <50% occurred in 78, 102, and 69 of 468 segments, although it disappeared in 55% of instances at subsequent examinations. Regional temporal variability was also marked: The absolute value of the difference in percent uptake was 10.1% +/- 7.3% from test 1 to test 2, 8.0% +/- 7.0% from test 1 to test 3, and 9.2% +/- 6.9% from test 2 to test 3. Overall from one test to another, uptake increased or decreased by >10% in 76 and in 116 of 468 segments, respectively.
The large spatial and temporal heterogeneity of the myocardial metabolic pattern, in cancer patients free of any disease, suggests a word of caution on the use of (18)F-FDG alone as a diagnostic tool for myocardial viability.
心脏（18）F-FDG摄取成像用于评估存活心肌的诊断。最初，冬眠心肌通过灌注缺损与相对保留的（18）F-FDG摄取之间的不匹配来识别，目前一些研究提出（18）F-FDG分布也可单独用于此目的。然而，在没有任何心脏疾病的癌症患者中也经常观察到严重的心肌（18）F-FDG摄取缺陷。本研究的目的是回顾性分析49例连续无心脏疾病的癌症患者在禁食条件下接受3次PET扫描的整体和局部（18）F-FDG心脏图像。
使用高分辨率PET/CT扫描仪采集图像。在融合的PET/CT图像上绘制三维感兴趣区，以测量左心室心肌的最大标准化摄取值（SUV(Myo)）以及左心室血液（SUV(LV)）和肝脏（SUV(Liver)）的平均SUV。通过自动识别心内膜和心外膜边界并将左心室分为20个节段，对26例患者的子样本进行局部心肌（18）F-FDG摄取分析。局部（18）F-FDG分布定义为每个区域中SUV(Myo)的百分比。
在整个研究过程中，SUV(Myo)以及SUV(LV)和SUV(Liver)平均没有变化。这种稳定性不是由心肌（18-）FDG分布的持续模式引起的。相反，它与随时间在两个方向上的重要变化有关。在所有3项研究中，局部（18）F-FDG分布在很大程度上是异质性的，每位患者的变异系数分别为18%±7%、18%±5%和17%±5%。在468个节段中的78个、102个和69个节段中出现（18）F-FDG摄取<50%，尽管在随后的检查中55%的情况消失了。局部时间变异性也很明显：从测试1到测试2，摄取百分比差异的绝对值为10.1%±7.3%，从测试1到测试3为8.0%±7.
