中央气道吸气相-呼气相的多层螺旋CT研究

目的 探讨呼吸运动对中央气道径线值的影响及其临床意义。方法 2016年3—7月郑州大学第一附属医院放射介入科招募60名健康成人志愿者进行前瞻性研究。其中男32例,女28例,年龄25~54(34.0±9.1)岁。志愿者均行胸部多层螺旋CT(MSCT)检查,于深吸气末、深呼气末分别扫描全肺,薄层图像结合多平面重建技术(MPR),使用特殊纵隔窗(窗宽500 HU,窗位-100 HU) 在吸气末、呼气末时测量中央气道横截面积,计算塌陷指数,测量左主支气管-右主支气管夹角(隆突角,∠C)、右上叶-中间支气管夹角(∠RI)、右中叶-右下叶支气管夹角(∠RMI)及左上叶-左下叶支气管夹角(∠LUI),并观察吸气末、呼气末时中央气道的形态改变。结果 深呼气末,中央气道横截面积均少于吸气末相,差异均有统计学意义(P值均<0.01)。气管塌陷指数为19.7%±8.6%;右主支气管、中间支气管、右上叶支气管、右中叶支气管和右下叶支气管塌陷指数分别为21.4%±9.6%、14.7%±6.2%、15.5%±5.7%、10.1%±3.6%、24.5%±9.1%;左主支气管、左上叶支气管、左下叶支气管塌陷指数分别为24.0%±9.4%、15.1%±5.0%、27.6%±10.7%。左侧中央气道中,各级支气管塌陷指数比较,差异有统计学意义(F=32.696, P<0.05);其中左主支气管、左下叶支气管的塌陷指数较大,与左上叶支气管塌陷指数比较,差异均有统计学意义(P值均<0.05)。右侧中央气道中,各级支气管塌陷指数比较,差异有统计学意义(F=38.154, P<0.05);其中右主支气管、右下叶支气管的塌陷指数较大,分别与右上叶支气管、中间支气管、右中叶支气管塌陷指数比较,差异均有统计学意义(P值均<0.05)。呼气末与吸气末时比较,∠C增大,∠RI、∠RMI、∠LUI均减小,差异均有统计学意义(P值均<0.01),其中∠LUI吸气-呼气差值最大。深吸气末时,中央气道的轴位横断面多为类圆形或卵圆形。深呼气末时,气管85%(51/60)、左主支气管70%(42/60)、右主支气管82%(49/60)呈后膜变平或轻度前弓形态。叶支气管断面形态改变不明显。结论 MSCT为观察和测量中央气道径线的有效手段,根据不同呼吸时相的气管及各级支气管的横截面积和夹角变化程度不同,有利于指导临床选择合适型号的气道支架,也有助于探讨和研发更具有生理适应性的气道支架。

Imaging study of inspiratory phase and expiratory phase of the central airway based on multi-slice spiral CT

Objective To explore the influence of respiratory motion on central airway values and its clinical significance.Methods Sixty healthy volunteers were selected and multi-slice spiral CT(MSCT) was used to scan the whole lung at the end of deep inspiration and at the end of expiration. There were 32 males and 28 females with an age ranged from 25 to 54 years, with an average age of (34±9.1) years. We used multiplanar reconstruction technique and used (window width 500 Hu, window level -100 Hu) to measure the cross-sectional area of the central airway at the end of inspiration and at the end of expiration. We calculated the collapse index and measured left principal bronchus-right principal bronchus (the angle of carina, ∠C), right upper lobe-intermediate bronchial angle (∠RI), right middle lobar bronchus-right inferior lobar bronchus angle (∠RMI), left upper lobe bronchus-left inferior lobar bronchus angle(∠LUI), respectively.Results At the end of expiration, the cross sectional areas of the central airway were reduced, the differences were statistically significant (all P values<0.05). The collapse index of tracheal is 19.7%±8.6%; Right principal bronchus, intermediate bronchus, right upper lobe bronchus, right middle lobar bronchus and right inferior lobar bronchus's collapse index was 21.4%±9.6%, 14.7%±6.2%, 15.5%±5.7%, 10.1%±3.6%, 24.5%±9.1%, respectively; Left principal bronchus, left upper lobe bronchus and left inferior lobar bronchus's collapse index was 24.0%±9.4%, 15.1%±5.0%, 27.6±10.7%, respectively. In the left central airway, there were significant differences in bronchial collapse index at different levels (F=32.696, P<0.05); The collapse index of the left principal bronchus and the left lower lobe bronchus was larger, and the difference was statistically significant compared with the left upper lobe bronchial collapse index (all P values<0.05); In the right central airway, there were significant differences in bronchial collapse index at different levels (F=38.154, P<0.05); The collapsible index of the right principal bronchus and right lower lobe bronchus were larger, and the difference was statistically significant compared with the right upper lobe bronchus, middle bronchus and right middle lobe bronchus (all P values <0.05). At the end of expiration, ∠C was increased, ∠RI, ∠RMI and ∠LUI was decreased, and the differences were statistically significant (all P values<0.01). Among them, ∠LUI had the greatest change. At the end of deep inspiration, the axial section of the central airway was mostly round or oval. At the end of expiratory, 51 cases (85%, 51/60) of trachea, 42 cases of left principal bronchus (70%, 42/60), 49 cases of right principal bronchus (82%, 49/60) showed posterior membrane flattening or slight anterior arch shape. The morphological change of lobar bronchus was not obvious.Conclusions MSCT is an effective tool for the observation and measurement of the central airway. The degree of change in the cross-sectional area and the angle of the central airway is different, it is helpful to guide the clinical selection of the appropriate type of airway stent, and also beneficial to explore and develop airway stents with more physiological adaptability.