Miller D G, Gilmour R F, Grossman Z D, Mallov S, Wistow B W, Rohner R F
J Nucl Med. 1977 Oct;18(10):1005-9.
The cardiac uptake of Tc-99m tagged skeletal agents was studied after myocardial injury produced by subcutaneous catecholamine injection and random foot-shock stress. Rats stressed for 2 hr developed microfocal myocardial injury, without gross change, whereas those stressed for 12 hr sustained more confluent and sometimes grossly visible damage. Tc-99m MDP and Tc-99m PPi concentrations in these hearts were significantly above control (undamaged) heart levels, producing positive gamma-camera images. Subcutaneous epinephrine injections resulted in grossly visible lesions, with tracer concentrations higher than those previously reported in vasoocclusive infarcts. We postulate that the stress-induced scattered microfocal lesions may accumulate radiopharmaceutical on a per-gram basis in the same way as the larger catecholamine-induced lesions, since tracer delivery to the injured areas in each case is probably less impeded than in frankly vasoocclusive models. Such microfoci, then, could provide an explanation for some of the "false positive" myocardial scans observed clinically.
在通过皮下注射儿茶酚胺和随机足部电击应激产生心肌损伤后，研究了锝-99m标记的骨显像剂的心脏摄取情况。应激2小时的大鼠出现微灶性心肌损伤，无肉眼可见变化，而应激12小时的大鼠则出现更融合且有时肉眼可见的损伤。这些心脏中的锝-99m亚甲基二膦酸盐（MDP）和锝-99m焦磷酸盐（PPi）浓度显著高于对照（未受损）心脏水平，产生阳性γ相机图像。皮下注射肾上腺素导致肉眼可见的病变，示踪剂浓度高于先前在血管闭塞性梗死中报道的浓度。我们推测，应激诱导的散在微灶性病变可能与较大的儿茶酚胺诱导病变一样，以每克为基础积累放射性药物，因为在每种情况下，示踪剂向损伤区域的输送可能比在明显血管闭塞模型中受到的阻碍更小。那么，这种微灶可能为临床上观察到的一些“假阳性”心肌扫描提供解释。
