Determination of regional ventilation and perfusion in the lung using xenon and computed tomography
Determination of regional ventilation and perfusion in the lung using xenon and computed tomography
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DOI：
10.1152/jappl.2001.91.4.1741
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发表时间：
2001-10-01
影响因子：
3.3
通讯作者：
Hlastala, MP
中科院分区：
文献类型：
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作者：
Kreck, TC;Krueger, MA;Hlastala, MP
我们提出了一个既能测量局部通气量(V)又能测量局部血流量(Q)的模型。在该模型中，氙气(Xe)洗涤时肺的局部放射性密度(Rd)是局部(V)/Dot(增加Rd)和(Q)/Dot(减少Rd)的函数。我们研究了5只麻醉、麻痹、机械通风、仰卧的绵羊。同时采集4个2.5 mm厚的CT图像，在每次Xe呼吸3min的末次吸气时，立即头侧至横隔膜。利用Xe洗涤过程中观察到的RD变化来确定区域(V)和(Q)Over Dot。对于16 mm(3)，(Q)/点(V)/点的变异系数(CV(Q)/点)=1.58+/-0.23，(V)/点(V)/点(CV(V)/点)=0.46+/-0.07，CV(Q)/点/CV(V)/点的比率=3.5+/-1.1。在1000 mm(3)尺度下，CV(Q)/点(1.21+/-0.37)和CV(Q)/点/CV(V)/点(2.4+/-1.2)的比率较小，而CV(V)/点(0.53+/-0.09)则不是很小。(V)点/(Q)点上的分布也具有尺度依赖性：16 mm(3)和1,000 mm(3)区域的(V)和(Q)点上的对数SD分别为0.79±/-0.05和0.85+/-0.10。用CT和Xe进行的(V)Over Dot和(Q)Over Dot测量也显示出垂直方向和等重力的不均一性，这是用其他方法描述的。CT扫描获得的Xe呼吸序列图像具有较高的空间分辨率，可以无创性地确定点上区域(V)和点上(Q)。
We propose a model to measure both regional ventilation ((V) over dot) and perfusion ((Q) over dot) in which the regional radiodensity (RD) in the lung during xenon (Xe) washin is a function of regional (V) over dot (increasing RD) and (Q) over dot (decreasing RD). We studied five anesthetized, paralyzed, mechanically ventilated, supine sheep. Four 2.5-mm-thick computed tomography (CT) images were simultaneously acquired immediately cephalad to the diaphragm at end inspiration for each breath during 3 min of Xe breathing. Observed changes in RD during Xe washin were used to determine regional (V) over dot and (Q) over dot. For 16 mm(3), displayed more variance than (V) over dot: the coefficient of variance of (Q) over dot (CV(Q) over dot) = 1.58 +/- 0.23, the CV of (V) over dot (CV(V) over dot) = 0.46 +/- 0.07, and the ratio of CV(Q) over dot to CV(V) over dot = 3.5 +/- 1.1. CV(Q) over dot (1.21 +/- 0.37) and the ratio of CV(Q) over dot to CV(V) over dot (2.4 +/- 1.2) were smaller at 1,000-mm(3) scale, but CV(V) over dot (0.53 +/- 0.09) was not, (V) over dot/(Q) over dot distributions also displayed scale dependence: log SD of (V) over dot and log SD of (Q) over dot were 0.79 +/- 0.05 and 0.85 +/- 0.10 for 16-mm(3) and 0.69 +/- 0.20 and 0.67 +/- 0.10 for 1,000-mm(3) regions of lung, respectively. (V) over dot and (Q) over dot measurements made with CT and Xe also demonstrate vertically oriented and isogravitational heterogeneity, which are described using other methodologies. Sequential images acquired by CT during Xe breathing can be used to determine both regional (V) over dot and (Q) over dot noninvasively with high spatial resolution.