Cohen Judith, Douma W Rob, van Ooijen Peter M A, Willems Tineke P, Dicken Volker, Kuhnigk Jan-Martin, ten Hacken Nick H T, Postma Dirkje S, Oudkerk Matthijs
Department of Pulmonology, University Medical Center Groningen, University of Groningen, the Netherlands.
J Comput Assist Tomogr. 2008 Jul-Aug;32(4):562-9. doi: 10.1097/RCT.0b013e31815f2bb0.
To assess the feasibility of volumetric and densitometric software to localize and quantify signs of regional air trapping after methacholine bronchoprovocations in asthma.
Eight atopic subjects with mild-to-moderate asthma using short-acting beta2-agonists only, with hyperresponsiveness to methacholine, were evaluated. Low-dose baseline expiratory 16-slice multidetector computed tomography scans before and after a methacholine bronchoprovocation were acquired. MeVisPULMO3D software (Bremen, Germany) was applied to the scans, providing quantitative information on volume and density measures of the total lung and each lobe.
After methacholine, the expiratory scan showed a median (interquartile range) increase in volume of 534 mL (357-1279 mL), a decrease in lung density (mean and 15th percentile) of 52 Hounsfield Units (HU) (116-39 HU) and 34 HU (78-25 HU), respectively, and an increase in percentage low attenuation areas of 3% (2%-6%) for the total lung, with similar patterns in individual lung lobes. The right and left lower lung lobes showed the largest increases in air trapping, 211 mL (117-363 mL) and 229 mL (155-315 mL), respectively, versus a volume increase of 70 mL (20-249 mL), 26 mL (-16-92 mL), and 91 mL (-28-241 mL) for the right upper, middle, and left upper lobes, respectively. Volume changes in the lower lobes were associated with baseline forced expiratory flow between 25% and 75% of forced vital capacity, whereas low attenuation areas changes in the lower lobes were not.
This study suggests that multidetector computed tomography scans are able to localize and quantify regional air trapping in asthma after methacholine bronchoprovocations. Volumetric measurements of the lobes as compared to densitometric measurements are superior in detecting local air trapping in gravity-dependent areas of the lung.
评估容积和密度测定软件在哮喘患者乙酰甲胆碱支气管激发试验后定位和量化局部空气潴留征象的可行性。
对8名仅使用短效β2受体激动剂、对乙酰甲胆碱反应性高的轻至中度哮喘特应性受试者进行评估。在乙酰甲胆碱支气管激发试验前后进行低剂量基线呼气期16层多排螺旋计算机断层扫描。将MeVisPULMO3D软件（德国不来梅）应用于扫描图像，以提供关于全肺及各肺叶容积和密度测量的定量信息。
乙酰甲胆碱激发试验后，呼气期扫描显示，容积中位数（四分位间距）增加534 mL（357 - 1279 mL），肺密度（平均值和第15百分位数）分别降低52亨氏单位（HU）（116 - 39 HU）和34 HU（78 - 25 HU），全肺低衰减区百分比增加3%（2% - 6%），各肺叶有相似表现。右肺下叶和左肺下叶空气潴留增加最多，分别为211 mL（117 - 363 mL）和229 mL（155 - 315 mL），而右上叶、中叶和左上叶容积增加分别为70 mL（20 - 249 mL）、26 mL（-16 - 92 mL）和91 mL（-28 - 241 mL）。下叶容积变化与基线用力肺活量25%至75%时的用力呼气流量相关，而下叶低衰减区变化与之无关。
本研究表明，多排螺旋计算机断层扫描能够在乙酰甲胆碱支气管激发试验后定位和量化哮喘患者的局部空气潴留。与密度测量相比，肺叶容积测量在检测肺重力依赖区的局部空气潴留方面更具优势。
