正常肺叶不同体位呼吸气薄层螺旋CT观察

目的探讨呼气相CT上肺内低密度区产生的原因。方法15例正常青年志愿者,年龄21~23岁,平均22岁。在右中肺门区,做仰卧与俯卧位深吸气屏气及深呼气屏气薄层螺旋CT扫描。对仰卧及俯卧位呼吸气相上中肺门区解剖结构相同的层面,进行肺叶面积及密度测量。计算肺叶吸气较呼气面积增加百分率及密度增加值。结果当右下叶处于下垂位,同层面肺叶膨胀性及密度改变均大于非下垂位,肺叶膨胀性与密度变化呈现高度相关(P<0.005)。结论呼气CT上肺内低密度区产生的因素有多种,其中肺内血流变化可直接影响肺密度,同时对肺叶膨胀性也有一定影响。

Spiral CT Observation of Normal Lung Lobes in Respiration on Different Position

Objective The study the formative causes of low dense area in lung on CT images during expiration.Methods This group included 15 young volunteers,mean age was 22 years.Thin sections of spiral CT at right middle hilum were scanned at suspended deep inspiration and deep expiration on both supine and prone positions.The density and area of lobes on matching structural images in the middle hilum at deep inhalation and exhalation were measured on the supine and prone.The increasing rate in area and absolute increasing value in attenuation as full inhalation comparing to full exhalation were calculated.Results Changes of distention and density in the same section of the right lower lobe on dependent position were greater than that on nondependent one.Correlation between distention and density of the lobes was high(P< 0.005).Conclusion There are several factors for local lower density of the lobe on expiratory CT.Changes of the lobes blood volume not only contribute to lung density,but also to the distension of the lobes somewhat.