Chilvers E R, Peters A M, George P, Hughes J M, Allison D J
Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London.
Clin Radiol. 1988 Nov;39(6):611-4. doi: 10.1016/s0009-9260(88)80065-5.
Calculation of the right-to-left shunt through pulmonary arteriovenous malformations (PAVMs) is important in assessing the effect of therapeutic embolisation or surgical resection. Previously, complicated physiological techniques using radiolabelled inert gases or the 100% oxygen breathing method were required. We describe a new method for quantitating the systemic uptake of intravenously injected 99Tcm albumin microspheres (99Tcm MS) which reflects shunt fraction since these particles do not normally traverse the pulmonary capillary bed. Seven patients with PAVMs were studied and shunt values obtained using 99Tcm MS were validated by simultaneous measurement of shunt fraction using the 100% oxygen method. By comparing radioactive counts in the injection dose to subsequent counts in the right kidney, which was taken as an index of systemic activity, accurate quantification of right-to-left shunt over a wide range of values was obtained (correlation coefficient against 100% oxygen method r = 0.993). The comparison of right kidney counts with total lung counts and total lung counts with injected dose counts, also indicators of shunt fraction, correlated less well with the oxygen method (r = 0.942 and r = 0.88 respectively). Use of 99Tcm labelled microspheres allows simple and precise measurement of right-to-left shunt in patients with PAVMs during routine isotope lung scanning.
计算经肺动静脉畸形（PAVM）的右向左分流对于评估治疗性栓塞或手术切除的效果很重要。以前，需要使用放射性标记惰性气体或100%氧气呼吸法等复杂的生理学技术。我们描述了一种定量静脉注射99锝标记白蛋白微球（99Tcm MS）全身摄取量的新方法，由于这些颗粒通常不会穿过肺毛细血管床，所以该方法能反映分流分数。对7例PAVM患者进行了研究，并通过使用100%氧气法同时测量分流分数来验证使用99Tcm MS获得的分流值。通过比较注射剂量中的放射性计数与随后右肾中的计数（将右肾计数作为全身活性指标），在很宽的值范围内获得了右向左分流的准确量化结果（与100%氧气法的相关系数r = 0.993）。右肾计数与全肺计数的比较以及全肺计数与注射剂量计数的比较（也是分流分数的指标），与氧气法的相关性较差（分别为r = 0.942和r = 0.88）。使用99Tcm标记的微球可在常规同位素肺扫描期间对PAVM患者的右向左分流进行简单而精确的测量。
