Verbanck S, Koneru S, Cohen M, Clarke S W, Agnew J E
Medical Physics Department, Royal Free Hospital and School of Medicine, London, United Kingdom.
J Nucl Med. 1993 Nov;34(11):1859-65.
Interregional sequential filling potentially affects lung ventilation imaging, depending on the distribution of the tracer within the inspired volume. We investigated its importance quantitatively under near tidal breathing conditions in the upright lung using a short-lived radioactive tracer. Ten normal volunteers performed two runs of 900-ml breaths (from functional residual capacity) in which 100 ml of 81mKr boli were delivered "early" or "late" in inspiration, i.e., 50 ml or 450 ml volumetric depth. Apex-to-base gradients in the vertical profile were -106 +/- 22 (s.e.) counts/cm (early) and -187 +/- 24 (s.e.) counts/cm (late). Ratios of upper-to-lower regional ventilation (U/L) were 0.88 +/- 0.01 (s.e.) (early) and 0.81 +/- 0.01 (s.e.) (late). Simulations with a compartment model show that a simple pattern of sequential filling can by itself account for the experimental results observed. Control over 81mKr delivery can be important to physiologically accurate assessment of ventilation-perfusion matching. Controlled delivery techniques could also modify effectiveness and targeting of other inhaled agents including therapeutic aerosols.
区域间的顺序填充可能会影响肺通气成像，这取决于示踪剂在吸入容积内的分布。我们使用一种短寿命放射性示踪剂，在近潮式呼吸条件下对直立肺中其重要性进行了定量研究。十名正常志愿者进行了两次900毫升呼吸（从功能残气量开始），其中100毫升81mKr团注在吸气“早期”或“晚期”注入，即容积深度为50毫升或450毫升。垂直剖面的尖部到基部梯度在早期为-106±22（标准误）计数/厘米，晚期为-187±24（标准误）计数/厘米。上区域与下区域通气（U/L）比值在早期为0.88±0.01（标准误），晚期为0.81±0.01（标准误）。用房室模型进行的模拟表明，简单的顺序填充模式本身就能解释所观察到的实验结果。对81mKr注入的控制对于通气-灌注匹配的生理准确评估可能很重要。受控注入技术还可能改变包括治疗性气雾剂在内的其他吸入剂的有效性和靶向性。
