Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wis 53705, USA.
J Allergy Clin Immunol. 2013 Feb;131(2):369-76.e1-5. doi: 10.1016/j.jaci.2012.10.032. Epub 2012 Dec 11.
Magnetic resonance imaging (MRI) with (3)He does not require ionizing radiation and has been shown to detect regional abnormalities in lung ventilation and structure in adults with asthma, but the method has not been extended to children with asthma. Measurements of regional lung ventilation and microstructure in subjects with childhood asthma could advance our understanding of disease mechanisms.
We sought to determine whether (3)He MRI in children can identify abnormalities related to the diagnosis of asthma or prior history of respiratory illness.
Forty-four children aged 9 to 10 years were recruited from a birth cohort at increased risk of asthma and allergic diseases. For each subject, a time-resolved 3-dimensional image series and a 3-dimensional diffusion-weighted image were acquired in separate breathing maneuvers. The numbers and sizes of ventilation defects were scored, and regional maps and statistics of average (3)He diffusion lengths were calculated.
Children with mild-to-moderate asthma had lower average root-mean-square diffusion length (X(rms)) values (P = .004), increased regional SD of diffusion length values (P = .03), and higher defect scores (P = .03) than those without asthma. Children with histories of wheezing illness with rhinovirus infection before the third birthday had lower X(rms) values (P = .01) and higher defect scores (P = .05).
MRI with (3)He detected more and larger regions of ventilation defect and a greater degree of restricted gas diffusion in children with asthma compared with those seen in children without asthma. These measures are consistent with regional obstruction and smaller and more regionally variable dimensions of the peripheral airways and alveolar spaces.
（3）氦磁共振成像（MRI）不使用电离辐射，已被证明可检测成人哮喘患者的肺通气和结构的区域性异常，但该方法尚未扩展到儿童哮喘患者。对儿童哮喘患者的区域性肺通气和微结构进行测量，可能会促进我们对疾病机制的理解。
我们试图确定（3）氦 MRI 是否可以识别与哮喘诊断或既往呼吸道疾病史相关的异常。
从一个具有较高哮喘和过敏性疾病风险的出生队列中招募了 44 名 9 至 10 岁的儿童。对于每个受试者，分别在不同的呼吸动作中采集时间分辨的 3 维图像序列和 3 维扩散加权图像。对通气缺陷的数量和大小进行评分，并计算区域性平均（3）氦扩散长度的图谱和统计数据。
轻度至中度哮喘患儿的平均均方根扩散长度（X（rms））值较低（P =.004），扩散长度值的区域标准差较高（P =.03），缺陷评分较高（P =.03），而无哮喘患儿的 X（rms）值较高（P =.004），扩散长度值的区域标准差较低（P =.03），缺陷评分较低（P =.03）。在三岁生日前曾因呼吸道合胞病毒感染而出现喘息性疾病的患儿的 X（rms）值较低（P =.01），缺陷评分较高（P =.05）。
与无哮喘患儿相比，（3）氦 MRI 检测到哮喘患儿有更多和更大的通气缺陷区域，以及更严重的气体扩散受限。这些指标与区域性阻塞以及外周气道和肺泡空间的更小且更具区域性变化的维度一致。
