Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark.
Department of Cardiology, The Heart Center, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark.
J Nucl Cardiol. 2019 Jun;26(3):798-809. doi: 10.1007/s12350-017-0994-9. Epub 2017 Jul 18.
Small-animal myocardial infarct models are frequently used in the assessment of new cardioprotective strategies. A validated quantification of perfusion using a non-cyclotron-dependent PET tracer would be of importance in monitoring response to therapy. We tested whether myocardial PET perfusion imaging is feasible with Rubidium-82 (Rb) in a small-animal scanner using a rat myocardial infarct model.
18 Sprague-Dawley rats underwent permanent coronary artery ligation (infarct group), and 11 rats underwent ischemia-reperfusion (reperfusion group) procedure. Rb-PET and magnetic resonance imaging (MRI) were conducted before and after the intervention. Perfusion was compared to both left ventricle ejection fraction (LVEF) and infarct size assessed by MRI.
Follow-up global Rb-uptake correlated significantly with infarct size (infarct group: r = -0.81, P < 0.001 and reperfusion group: r = -0.61, P = 0.04). Only Rb-uptake in the infarct group correlated with LVEF. At follow-up, a higher segmental Rb-uptake in the infarct group was associated with better wall motion (β = 0.034, CI [0.028;0.039], P < 0.001, R = 0.30), and inversely associated with scar transmurality (β = -2.4 [-2.6; -2.2], P < 0.001, R = 0.59). The associations were similar for the reperfusion group.
Rb-PET is feasible in small animal scanners despite the long positron range and enables fast and time-efficient myocardial perfusion imaging in rat models.
小动物心肌梗死模型常用于评估新的心脏保护策略。使用非回旋加速器依赖性 PET 示踪剂进行灌注的验证量化对于监测治疗反应非常重要。我们测试了使用小型动物扫描仪中的铷-82（Rb）进行心肌 PET 灌注成像是否可行，该扫描仪使用大鼠心肌梗死模型。
18 只斯普拉格-道利大鼠接受永久性冠状动脉结扎（梗死组），11 只大鼠接受缺血再灌注（再灌注组）手术。在干预前后进行 Rb-PET 和磁共振成像（MRI）。灌注与左心室射血分数（LVEF）和 MRI 评估的梗死面积进行比较。
随访的整体 Rb 摄取与梗死面积显著相关（梗死组：r=-0.81，P<0.001；再灌注组：r=-0.61，P=0.04）。只有梗死组的 Rb 摄取与 LVEF 相关。在随访时，梗死组较高的节段性 Rb 摄取与更好的壁运动相关（β=0.034，CI [0.028;0.039]，P<0.001，R=0.30），并与瘢痕透壁性呈负相关（β=-2.4 [-2.6; -2.2]，P<0.001，R=0.59）。再灌注组也存在类似的关联。
尽管正电子射程较长，但 Rb-PET 在小型动物扫描仪中是可行的，并且能够在大鼠模型中快速有效地进行心肌灌注成像。
