Spector Z Z, Emami K, Fischer M C, Zhu J, Ishii M, Yu J, Kadlecek S, Driehuys B, Panettieri R A, Lipson D A, Gefter W, Shrager J, Rizi R R
Department of Radiology, University of Pennsylvania School of Medicine, Stellar-Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA 19104, USA.
Acad Radiol. 2004 Oct;11(10):1171-9. doi: 10.1016/j.acra.2004.08.001.
The aim of this study was to establish a standardized procedure for the measurement of regional fractional ventilation in a healthy rat model as a baseline for further studies of pulmonary disorder models.
The lungs of five healthy male Sprague-Dawley rats were imaged using hyperpolarized helium-3 magnetic resonance imaging. From these images, regional fractional ventilation was calculated and maps generated detailing the distribution of fractional ventilation in the lung. The 1.56 mm x 1.56 mm x 4 mm regions of interest were assigned on 5 cm x 5 cm field of view lung maps. Histograms were also generated showing the frequency distribution of fractional ventilation values. To compare fractional ventilation values between animals, the ventilation procedure was standardized to results from individual pulmonary function tests. Each animal's spontaneous tidal volume, respiratory rate, and inspiration percentage (percent of total respiratory cycle in inspiration) were used in their mechanical ventilation settings.
Results were similar among all five healthy rats based on examination of ventilation distribution maps and frequency distribution histograms. Mean (0.13) and standard deviation (0.07) were calculated for fractional ventilation in each animal. However, these values were determined to be influenced by slice selection, and therefore the maps and histograms were favored in analysis of results.
This study shows consistent results in healthy rat lungs and will serve as a baseline study for future measurements in emphysematous rat lungs.
本研究的目的是在健康大鼠模型中建立一种标准化程序，用于测量局部肺通气分数，作为进一步研究肺部疾病模型的基线。
使用超极化氦-3磁共振成像对五只健康雄性Sprague-Dawley大鼠的肺部进行成像。从这些图像中计算局部肺通气分数，并生成详细显示肺内通气分数分布的图谱。在5 cm×5 cm视野的肺图谱上指定1.56 mm×1.56 mm×4 mm的感兴趣区域。还生成了直方图，显示通气分数值的频率分布。为了比较不同动物之间的通气分数值，将通气程序标准化为个体肺功能测试的结果。在机械通气设置中使用每只动物的自发潮气量、呼吸频率和吸气百分比（吸气占总呼吸周期的百分比）。
根据通气分布图和频率分布直方图检查，所有五只健康大鼠的结果相似。计算每只动物通气分数的平均值（0.13）和标准差（0.07）。然而，这些值被确定受切片选择的影响，因此在结果分析中更倾向于使用图谱和直方图。
本研究在健康大鼠肺中显示出一致的结果，并将作为未来对肺气肿大鼠肺进行测量的基线研究。
