de Lange Eduard E, Altes Talissa A, Patrie James T, Parmar Jaywant, Brookeman James R, Mugler John P, Platts-Mills Thomas A E
Department of Radiology, University of Virginia, Charlottesville, VA 22908, USA.
J Allergy Clin Immunol. 2007 May;119(5):1072-8. doi: 10.1016/j.jaci.2006.12.659. Epub 2007 Mar 13.
It is unknown whether focal changes of airflow obstruction within the lungs of patients with asthma vary or are fixed in location with time or repeated bronchoconstriction. With hyperpolarized helium-3 magnetic resonance (H(3)HeMR) imaging, the airspaces are depicted and focal areas of airflow obstruction are shown as "ventilation defects."
To investigate the regional changes of airflow obstruction with time and repeated bronchoconstriction.
H(3)HeMR and spirometry were performed before (pre) and immediately after (post) methacholine challenge in 10 young patients with asthma on 2 days that were 7-476 days (mean, 185.3 +/- 37.2 days) apart. Pair-wise image comparisons were performed to determine the change in location of ventilation defects within the lung and their change in size.
When comparing premethacholine versus premethacholine and postmethacholine versus post-methacholine images of the 2 days, 41% +/- 10% and 69% +/- 5% (P = .017) of defects, respectively, were in the same location, and of those, 69% +/- 12% and 43% +/- 5% (P = .022), respectively, did not change size. Comparing premethacholine versus postmethacholine images, 58% +/- 9% of defects were in the same location on day 1 and 73% +/- 7% (P = .088) on day 2. On both days, the percent increase in defect number from premethacholine to postmethacholine was much greater than the percent decrease in spirometric values (P < .001).
Many of the ventilation defects persisted or recurred in the same location with time or repeated bronchoconstriction, suggesting that the regional changes of airflow obstruction are relatively fixed within the lung.
The findings give new insight into the regional airflow variability within the lungs of patients with asthma.
哮喘患者肺部气流阻塞的局灶性变化是否会随时间、反复支气管收缩而改变或固定在某一位置尚不清楚。通过超极化氦-3磁共振（H(3)HeMR）成像，可以描绘出气道空间，气流阻塞的局灶性区域表现为“通气缺陷”。
研究气流阻塞的区域变化随时间及反复支气管收缩的情况。
对10名年轻哮喘患者在相隔7 - 476天（平均185.3±37.2天）的2天内，于乙酰甲胆碱激发试验前（预）和激发后即刻（后）进行H(3)HeMR和肺功能测定。进行两两图像比较，以确定肺内通气缺陷位置的变化及其大小的变化。
比较两天的乙酰甲胆碱激发试验前与激发试验前、激发试验后与激发试验后的图像，分别有41%±10%和69%±5%（P = 0.017）的缺陷位于相同位置，其中分别有69%±12%和43%±5%（P = 0.022）的缺陷大小未改变。比较乙酰甲胆碱激发试验前与激发试验后的图像，第1天有58%±9%的缺陷位于相同位置，第2天为73%±7%（P = 0.088）。在这两天中，从乙酰甲胆碱激发试验前到激发试验后缺陷数量的增加百分比远大于肺功能测定值的降低百分比（P < 0.001）。
许多通气缺陷随时间或反复支气管收缩在相同位置持续存在或复发，提示气流阻塞的区域变化在肺内相对固定。
这些发现为哮喘患者肺内区域气流变异性提供了新的见解。
