vom Dahl J, Muzik O, Wolfe E R, Allman C, Hutchins G, Schwaiger M
Department of Internal Medicine, University of Michigan, Ann Arbor, USA.
Circulation. 1996 Jan 15;93(2):238-45. doi: 10.1161/01.cir.93.2.238.
Recent reports have demonstrated the clinical use of rubidium-82 chloride (Rb-82) in combination with positron emission tomography (PET) not only as a tracer of myocardial blood flow but also as a marker of cell membrane integrity using static imaging early and late after tracer injection. The purpose of this study was to compare myocardial Rb-82 kinetics assessed by dynamic PET imaging as a marker for tissue viability with regional fluorine-18 fluorodeoxyglucose (FDG) uptake in patients with coronary artery disease.
Twenty-seven patients with angiographically proven coronary artery disease and 5 subjects with a low likelihood for coronary artery disease underwent dynamic PET imaging under resting conditions using Rb-82 and FDG. Both image sequences served as input data for a semiautomated regional analysis program. This program generated polar maps representing Rb-82 tissue half-life and FDG utilization assessed by Patlak's approach. Myocardial tissue viability was visually determined from static Rb-82 and FDG images. Regions were categorized as normal, ischemically compromised, and scar tissue. Their coordinates were subsequently copied to the functional polar maps for further analyses. In normal subjects, Rb-82 tissue half-life was homogeneous throughout the left ventricle (90 +/- 11 seconds). In coronary patients, differences between Rb-82 tissue half-lives in normal and scar tissue were highly significant (95 +/- 10 and 57 +/- 15 seconds, respectively; P < .0001). FDG uptake in these two tissue groups was 78 +/- 12% and 40 +/- 13%, respectively (P < .0001). Ischemically compromised tissue with reduced perfusion but maintained FDG uptake displayed an Rb-82 half-life of 75 +/- 9 seconds, indicating active cellular tracer retention, which was significantly different from scar tissue. Overall agreement of tissue categorization as either viable or scar was 86% between Rb-82 kinetics and FDG utilization. In a subgroup of 11 patients with all three tissue types within one image set, Rb-82 tissue half-life discriminated between normal, ischemic, and scar tissue (97 +/- 9, 75 +/- 9, and 60 +/- 15 seconds, respectively; P < .01).
This study demonstrated a significant relationship between cell membrane integrity as assessed by dynamic Rb-82 PET imaging and myocardial glucose utilization as a marker for tissue viability. In regions with reduced perfusion, Rb-82 kinetics was different in compromised but metabolically active and irreversibly injured myocardium. The predictive value of this approach must be evaluated in follow-up studies.
最近的报告表明，氯化铷-82（Rb-82）与正电子发射断层扫描（PET）联合使用，不仅可作为心肌血流示踪剂，还可在示踪剂注射后的早期和晚期静态成像中作为细胞膜完整性的标志物。本研究的目的是比较通过动态PET成像评估的心肌Rb-82动力学作为组织存活标志物与冠状动脉疾病患者局部氟-18氟脱氧葡萄糖（FDG）摄取情况。
27例经血管造影证实患有冠状动脉疾病的患者和5例冠状动脉疾病可能性较低的受试者在静息状态下使用Rb-82和FDG进行了动态PET成像。两个图像序列均作为半自动区域分析程序的输入数据。该程序生成了代表Rb-82组织半衰期和通过Patlak方法评估的FDG利用率的极坐标图。从静态Rb-82和FDG图像中直观地确定心肌组织存活情况。区域被分类为正常、缺血受损和瘢痕组织。随后将它们的坐标复制到功能极坐标图中进行进一步分析。在正常受试者中，整个左心室的Rb-82组织半衰期均匀（90±11秒）。在冠心病患者中，正常组织和瘢痕组织的Rb-82组织半衰期差异非常显著（分别为95±10秒和57±15秒；P<.0001）。这两个组织组中的FDG摄取分别为78±12%和40±13%（P<.0001）。灌注减少但FDG摄取保持的缺血受损组织显示Rb-82半衰期为75±9秒，表明有活性细胞示踪剂滞留，这与瘢痕组织有显著差异。Rb-82动力学和FDG利用率之间将组织分类为存活或瘢痕的总体一致性为86%。在一个图像集中包含所有三种组织类型的11例患者亚组中，Rb-82组织半衰期区分了正常、缺血和瘢痕组织（分别为97±9秒、75±9秒和60±15秒；P<.01）。
本研究表明，通过动态Rb-82 PET成像评估的细胞膜完整性与作为组织存活标志物的心肌葡萄糖利用之间存在显著关系。在灌注减少的区域，Rb-82动力学在受损但代谢活跃和不可逆损伤的心肌中有所不同。这种方法的预测价值必须在后续研究中进行评估。
