Wang Ke, Pan Ting, Yang Hao, Ruan Weiwei, Zhong Jianping, Wu Guangyao, Zhou Xin
Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China.
Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China.
J Thorac Dis. 2017 Aug;9(8):2572-2578. doi: 10.21037/jtd.2017.08.39.
The purpose of this study was to explore the feasibility of hyperpolarized Xe diffusion-weighted imaging (DWI) for the evaluation of pulmonary microstructural changes in the presence of pancreatic porcine elastase (PPE)-induced pulmonary emphysema rat model.
Sixteen male Sprague-Dawley (SD) rats were randomly divided into two groups, the emphysema model group and control group. Experimental emphysematous models were made by instilling elastase into rat lungs of model group, the control group were instilled with isodose saline. Hyperpolarized Xe magnetic resonance imaging (MRI) and histology were performed in all 16 rats after 30 days. DWIs were performed on a Bruker 7.0 T micro MRI, and the apparent diffusion coefficients (ADCs) were measured in all rats. Mean linear intercepts (MLIs) of pulmonary alveoli were measured on histology. The statistical analyses were performed about the correlation between the mean ADC of hyperpolarized Xe in the whole lung and MLI of pulmonary histology metric.
The pulmonary emphysematous model was successfully confirmed by the histology and all scans were also successful. The ADC value of Xe in the model group (0.0313±0.0005 cm/s) was significantly increased compared with that of the control group (0.0288±0.0007 cm/s, P<0.0001). Morphological differences such as MLI of pulmonary alveoli were observed between the two groups, the MLI of pulmonary alveoli in model group significantly increased (91±5 µm) than that of control group (50±3 µm, P<0.0001). Furthermore, the ADCs was moderately correlated with MLIs (r=0.724, P<0.01).
These results indicate that Xe ADC value can quantitatively reflect the alveolar space enlargement and it is a promising biomarker for the detection of pulmonary emphysema.
本研究旨在探讨超极化氙扩散加权成像（DWI）在评估猪胰腺弹性蛋白酶（PPE）诱导的肺气肿大鼠模型中肺微结构变化的可行性。
16只雄性Sprague-Dawley（SD）大鼠随机分为两组，即肺气肿模型组和对照组。通过向模型组大鼠肺内注入弹性蛋白酶建立实验性肺气肿模型，对照组注入等剂量生理盐水。30天后对所有16只大鼠进行超极化氙磁共振成像（MRI）和组织学检查。在Bruker 7.0 T微型MRI上进行DWI，并测量所有大鼠的表观扩散系数（ADC）。在组织学上测量肺泡的平均线性截距（MLI）。对全肺超极化氙的平均ADC与肺组织学指标MLI之间的相关性进行统计分析。
组织学成功证实了肺气肿模型，所有扫描也均成功。模型组氙的ADC值（0.0313±0.0005 cm/s）与对照组（0.0288±0.0007 cm/s，P<0.0001）相比显著升高。两组间观察到肺泡MLI等形态学差异，模型组肺泡MLI显著增加（91±5 µm），高于对照组（50±3 µm，P<0.0001）。此外，ADC与MLI呈中度相关（r=0.724，P<0.01）。
这些结果表明，氙ADC值可定量反映肺泡腔扩大，是检测肺气肿的一个有前景的生物标志物。
