Poster Presentation 23rd International Society of Magnetic Resonance Conference 2023

Lung Compliance Imaging with Hyperpolarized 129Xe MRI (#317)

Ming Zhang 1 2 , Haidong Li 1 2 , Hongchuang Li 1 2 , Xiaoling Liu 1 2 , Xiuchao Zhao 1 2 , Yu Zheng 1 2 , Yeqing Han 1 2 , Fumin Guo 1 2 , Xianping Sun 1 2 , Chaohui Ye 1 2 , Xin Zhou 1 2
  1. 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, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China
  2. University of Chinese Academy of Sciences, Beijing, China

Lung compliance (LC) refers to the ability of the lungs to stretch and expand, and is defined as the changes in lung volume caused by changes in unit pressure. LC is generally measured globally in clinic. Image modalities could provide a way to measure the regional LC. Hyperpolarized 129Xe MRI has been regarded as a promising lung functional imaging modality for assessing regional lung microstructure and gas exchange function. Hyperpolarized 129Xe MRI could image the distribution of inhaled gas in alveoli and distal airway, allowing the accurate measurement of lung volume. This study was intended to demonstrate the feasibility of using hyperpolarized 129Xe MRI to measure regional lung compliance.

Twenty Sprague-Dawley rats were divided into two groups (n = 10) randomly. The fibrosis group was intratracheally instilled with with 0.4 mL solution of bleomycin (2.5 U/kg body weight), while the control group was treated with an equivalent volume of normal saline. Pulmonary function tests (PFTs), 129Xe MRI, and computerized tomography (CT) were performed on day 21 to day 24 after treatment. 3D Lung compliance images were derived from 129Xe MRI by registering the ventilation images to that with minimal pressure using Advanced Normalization Toolkits. 3D lung compliance images were also obtained using CT imaging as a cross-validation.

The measured quasi-static compliance (Cqs) with PFTs for healthy rats and fibrosis rats were 0.89 ± 0.08 and 0.48 ± 0.12 ml/cm H2O, respectively (p < 0.001). The measured lung compliance with 129Xe MRI was 0.47 ± 0.05 mL/cm H2O for the healthy group and 0.39 ± 0.07 mL/cm H2O for the fibrosis group. Both image-derived global and regional lung compliance by 129Xe MRI correlates well with Cqs (Global, r = 0.891; Regional, r = 0.873). Moreover, direction-dependencies of lung compliance were observed for the first time with 129Xe MRI and weakened direction-dependencies of lung compliance were found in the fibrosis group.

Our results demonstrate the feasibility of imaging lung compliance using hyperpolarized 129Xe MRI, and the potential of such a method for characterizing lung diseases that are related to elastic dysfunction.