Premature infants often require mechanical ventilation and oxygen therapy which can result in bronchopulmonary dysplasia (BPD), characterized by developmental arrest and impaired lung function. Conventional clinical methods for assessing the prenatal lung are not adequate for the detection and assessment of long-term health risks in infants with BPD, highlighting the need for a non-invasive tool for the characterization of lung microstructure and function. Theoretical diffusion models, like the Model of Xenon Exchange (MOXE), interrogate alveolar gas exchange by predicting the uptake of inert Hyperpolarized (HP) ¹²⁹Xe gas measured with HP ¹²⁹Xe magnetic resonance spectroscopy (MRS). To investigate HP ¹²⁹Xe MRS as a tool for non-invasive characterization of pulmonary microstructural and functional changes in vivo, HP ¹²⁹Xe gas exchange data were acquired in an oxygen exposure rat model of BPD that recapitulates the fewer and larger distal airways and pulmonary vascular stunting characteristics of BPD. Gas exchange parameters from MOXE, including airspace mean chord length (L­_m), apparent hematocrit in the pulmonary capillaries (HCT), and pulmonary capillary transit time (t_x), were compared with airspace mean axis length and area density (MAL and ρ­_A) and percentage area of tissue and air (PTA and PAA) from histology. L­_m was significantly larger in the exposed rats (p=0.003) and correlated with MAL, ρ­_A,PTA, and PAA (0.59<|ρ|<0.66 and p<0.05). Observed increase in HCT (p=0.012) and changes in t_x are also discussed. These findings support the use of HP ¹²⁹Xe MRS for detecting fewer, enlarged distal airways in this rat model of BPD, and potentially in humans.

中文翻译：

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支气管肺发育不良大鼠模型中的超极化 129Xe 磁共振光谱

早产儿通常需要机械通气和氧疗，这会导致支气管肺发育不良 (BPD)，其特征是发育停滞和肺功能受损。用于评估产前肺的常规临床方法不足以检测和评估 BPD 婴儿的长期健康风险，这突出了对肺微观结构和功能表征的非侵入性工具的需求。理论扩散模型，如氙气交换模型 (MOXE)，通过预测惰性超极化 (HP) ¹²⁹ Xe 气体的吸收，用 HP ¹²⁹ Xe 磁共振波谱 (MRS)测量来询问肺泡气体交换。调查 HP ¹²⁹Xe MRS 作为一种非侵入性表征体内肺微观结构和功能变化的工具，在 BPD 的氧气暴露大鼠模型中获得了HP ¹²⁹ Xe 气体交换数据，该模型概括了 BPD 较少和较大的远端气道和肺血管发育不良特征. 从MOXE气体交换的参数，包括空域平均弦长（L-_米），在肺毛细血管表观比容（HCT），和肺毛细血管过境时间（t _X），用空域平均轴线长度和面积密度（MAL和ρ-相比_A ) 和来自组织学的组织和空气面积百分比（PTA 和 PAA）。L-_米是在暴露大鼠显著更大（p值= 0.003），并用MAL，ρ相关_一，PTA 和 PAA（0.59<|ρ|<0.66 和 p<0.05）。还讨论了观察到的 HCT 增加 (p=0.012) 和 t _{x 的}变化。这些发现支持使用 HP ¹²⁹ Xe MRS 检测 BPD 大鼠模型中更少、扩大的远端气道，并可能在人类中检测到。