Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Poongnap-dong, Songpa-gu, Seoul 138-736, Korea.
Radiology. 2010 Jun;255(3):790-8. doi: 10.1148/radiol.10090947.
To determine the feasibility of the use of xenon-enhanced dynamic dual-energy computed tomography (CT) for visualization and quantitative assessment of collateral ventilation in a canine model with bronchial obstruction.
This study was approved by the institutional animal care and use committee. One segmental bronchus was occluded in nine dogs (weight range, 20-25 kg). Dynamic dual-energy CT scanning was performed by using dual-source CT during the wash-in-washout study of xenon inhalation via mechanical ventilation. Imaging parameters were 14 x 1.2-mm collimation, 40 mAs (effective) at 140 kV and 170 mAs (effective) at 80 kV, pitch of 0.45, and 0.33-second rotation time. By using dual-energy software, CT images and xenon maps were reconstructed. CT attenuation values were measured in the airways proximal to obstruction (AW(PROX)) and airways distal to obstruction (AW(DIST)) and at the parenchyma with patent airways (P(PATE)) and parenchyma with obstructed airways (P(OBST)). CT attenuation values on dynamic xenon maps were plotted with exponential function; ventilation parameters, including velocity of ventilation (K value), magnitude of ventilation (A value), and time of arrival (TOA), were calculated on the basis of the Kety model.
In all animals, delayed and weaker xenon enhancement was identified at the airway and parenchyma distal to obstruction. For the A value, in the wash-in study, the differences between AW(PROX) and AW(DIST) and between P(PATE) and P(OBST) were significant (71.80 and 57.64, P = .05; 51.86 and 37.52 HU, P = .02). The K value of P(OBST) was lower than that of P(PATE) in the wash-in study (0.006 and 0 .010, P = .06). Mean and standard deviation for TOA were observed in the following increasing order: AW(PROX) ([3.50 +/- 7.70] x 10(-6) sec), P(PATE) (4.58 +/- 2.83), AW(DIST) (9.20 +/- 6.87), and P(OBST) (21.00 +/- 13.44).
Collateral ventilation in a canine model with bronchial obstruction can be quantitatively assessed by using xenon-enhanced dynamic dual-energy CT.
通过使用氙气增强动态双能 CT 来观察和定量评估犬支气管阻塞模型中的侧支通气。
本研究经机构动物护理和使用委员会批准。通过机械通气吸入氙气进行洗脱研究，使用双源 CT 在 9 只犬（体重范围，20-25kg）中对一个节段性支气管进行阻塞。成像参数为 14x1.2mm 准直器，140kV 时 40mAs（有效）和 80kV 时 170mAs（有效），螺距为 0.45，旋转时间为 0.33 秒。通过使用双能软件，重建 CT 图像和氙气图。在阻塞近端气道（AW(PROX)）、阻塞远端气道（AW(DIST)）、通气正常的肺实质（P(PATE)）和通气异常的肺实质（P(OBST)）测量 CT 衰减值。用指数函数绘制动态氙气图上的 CT 衰减值；基于 Kety 模型计算通气参数，包括通气速度（K 值）、通气幅度（A 值）和到达时间（TOA）。
在所有动物中，均在阻塞的气道和肺实质远端发现延迟和较弱的氙气增强。在吸入研究中，A 值在 AW(PROX)和 AW(DIST)之间以及 P(PATE)和 P(OBST)之间存在显著差异（71.80 和 57.64，P=0.05；51.86 和 37.52HU，P=0.02）。在吸入研究中，P(OBST)的 K 值低于 P(PATE)（0.006 和 0.010，P=0.06）。TOA 的平均值和标准差依次为：AW(PROX)（[3.50+/-7.70]x10(-6)sec）、P(PATE)（4.58+/-2.83）、AW(DIST)（9.20+/-6.87）和 P(OBST)（21.00+/-13.44）。
通过使用氙气增强动态双能 CT 可以定量评估犬支气管阻塞模型中的侧支通气。
