Buckberg G D
Division of Thoracic Surgery, UCLA School of Medicine 90024.
Ann Thorac Surg. 1975 Jul;20(1):46-51. doi: 10.1016/s0003-4975(10)63850-7.
Radioactive microspheres accurately measure total coronary blood flow (+/- 10%) if the heart contains at least 400 spheres. Precision of the microsphere method depends upon the number of spheres in the region of interest and the reference sample, not on the radioactivity. Reliable flow can be calculated from reference samples collected from any vessel (carotid or femoral artery or aorta) in the beating, working heart and during cardiopulmonary bypass if the sample contains a minimum of 400 spheres. Spheres of 9 mu are distributed in the heart like diffusible indicators, while spheres greater than 9 mu preferentially stream to the endocardium, causing subendocardial flow to be overestimated. This overestimate is lessened with 15 mu spheres and can be readily taken into account. The microsphere method provides information about flow (ml/100 gm tissue/min) and allows comparisons with other regions (endocardial/epicardial flow ratios) but does not provide information about the adequacy of regional flow or its distribution; this must be assessed by biochemical, histochemical, and functional analysis.
如果心脏中至少含有400个微球，放射性微球可精确测量总冠状动脉血流量（误差在±10%以内）。微球法的精确度取决于感兴趣区域和参考样本中的微球数量，而非放射性。如果样本中至少含有400个微球，那么在跳动的、工作的心脏以及体外循环期间，从任何血管（颈动脉、股动脉或主动脉）采集的参考样本都能够计算出可靠的血流量。9微米的微球像可扩散指示剂一样分布在心脏中，而大于9微米的微球则优先流向心内膜，导致心内膜下血流被高估。使用15微米的微球可减少这种高估，并且能够很容易地加以考虑。微球法可提供血流量信息（毫升/100克组织/分钟），并能与其他区域进行比较（心内膜/心外膜血流比率），但无法提供区域血流充足性或其分布的信息；这必须通过生化、组织化学和功能分析来评估。
