Altes Talissa A, Mata Jaime, de Lange Eduard E, Brookeman James R, Mugler John P
Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.
J Magn Reson Imaging. 2006 Dec;24(6):1277-83. doi: 10.1002/jmri.20723.
To determine whether hyperpolarized helium-3 (HHe) diffusion MR can detect the expected enlargement of alveoli that occurs with lung growth during childhood.
A total of 29 normal subjects aged four to 30 years underwent HHe diffusion MR imaging with the b-value pair 0, 1.6 second/cm(2). A second acquisition during a separate breathhold was performed using the b-value pair 0, 4 second/cm(2) to evaluate the dependence on b-value. The mean apparent diffusion coefficient (ADC) and lung volume for each acquisition and each subject was determined.
Subjects as young as four years of age were able to cooperate with the imaging procedure. The mean ADC increased with increasing subject age (r = 0.8; P < 0.001), with a 55% increase in mean ADC from the youngest to oldest subject. Lung volumes measured on MR were highly repeatable for the two HHe MR acquisitions (r = 0.980, P < 0.001). The mean ADC values measured with the two different b-value pairs were highly correlated (r = 0.975; P < 0.001), but the higher b-value pair resulted in slightly lower mean ADCs (P < 0.001).
HHe diffusion MR appears to detect the expected increase in alveolar size during childhood, and thus HHe MR may be a noninvasive method to assess development of the lung microstructure.
确定超极化氦-3（HHe）扩散磁共振成像（MR）能否检测出儿童期肺生长过程中预期出现的肺泡增大。
共有29名年龄在4至30岁的正常受试者接受了b值为0、1.6秒/厘米²的HHe扩散MR成像检查。在单独的屏气期间进行了第二次采集，使用b值为0、4秒/厘米²来评估对b值的依赖性。确定了每次采集和每个受试者的平均表观扩散系数（ADC）和肺容积。
年仅4岁的受试者就能配合成像程序。平均ADC随受试者年龄的增加而增加（r = 0.8；P < 0.001），从最年幼到最年长的受试者，平均ADC增加了55%。在两次HHe MR采集中，MR测量的肺容积具有高度可重复性（r = \alpha980，P < 0.001）。用两种不同b值对测量的平均ADC值高度相关（r = 0.975；P < 0.001），但较高b值对导致平均ADC略低（P < 0.001）。
HHe扩散MR似乎能检测出儿童期肺泡大小的预期增加，因此HHe MR可能是一种评估肺微结构发育的非侵入性方法。
