Physiological Gas Exchange Mapping of Hyperpolarized Xe Using Spiral-IDEAL and MOXE in a Model of Regional Radiation-induced Lung Injury
Overview
Affiliations
Purpose: To map physiological gas exchange parameters using dissolved hyperpolarized (HP) Xe in a rat model of regional radiation-induced lung injury (RILI) with spiral-IDEAL and the model of xenon exchange (MOXE). Results are compared to quantitative histology of pulmonary tissue and red blood cell (RBC) distribution.
Methods: Two cohorts (n = 6 each) of age-matched rats were used. One was irradiated in the right-medial lung, producing regional injury. Gas exchange was mapped 4 weeks postirradiation by imaging dissolved-phase HP Xe using spiral-IDEAL at five gas exchange timepoints using a clinical 1.5 T scanner. Physiological lung parameters were extracted regionally on a voxel-wise basis using MOXE. Mean gas exchange parameters, specifically air-capillary barrier thickness (δ) and hematocrit (HCT) in the right-medial lung were compared to the contralateral lung as well as nonirradiated control animals. Whole-lung spectroscopic analysis of gas exchange was also performed.
Results: δ was significantly increased (1.43 ± 0.12 μm from 1.07 ± 0.09 μm) and HCT was significantly decreased (17.2 ± 1.2% from 23.6 ± 1.9%) in the right-medial lung (i.e., irradiated region) compared to the contralateral lung of the irradiated rats. These changes were not observed in healthy controls. δ and HCT correlated with histologically measured increases in pulmonary tissue heterogeneity (r = 0.77) and decreases in RBC distribution (r = 0.91), respectively. No changes were observed using whole-lung analysis.
Conclusion: This work demonstrates the feasibility of mapping gas exchange using HP Xe in an animal model of RILI 4 weeks postirradiation. Spatially resolved gas exchange mapping is sensitive to regional injury between cohorts that was undetected with whole-lung gas exchange analysis, in agreement with histology. Gas exchange mapping holds promise for assessing regional lung function in RILI and other pulmonary diseases.
Doganay O, Kim M, Gleeson F Eur Radiol. 2022; 33(5):3322-3331.
PMID: 36547671 DOI: 10.1007/s00330-022-09343-9.
Preclinical MRI Using Hyperpolarized Xe.
Kadlecek S, Friedlander Y, Virgincar R Molecules. 2022; 27(23).
PMID: 36500430 PMC: 9738892. DOI: 10.3390/molecules27238338.
In vivo methods and applications of xenon-129 magnetic resonance.
Marshall H, Stewart N, Chan H, Rao M, Norquay G, Wild J Prog Nucl Magn Reson Spectrosc. 2021; 122:42-62.
PMID: 33632417 PMC: 7933823. DOI: 10.1016/j.pnmrs.2020.11.002.
Ruppert K, Amzajerdian F, Xin Y, Hamedani H, Loza L, Achekzai T Magn Reson Med. 2020; 84(6):3027-3039.
PMID: 32557808 PMC: 8088830. DOI: 10.1002/mrm.28329.
Virgincar R, Nouls J, Wang Z, Degan S, Qi Y, Xiong X Sci Rep. 2020; 10(1):7385.
PMID: 32355256 PMC: 7193602. DOI: 10.1038/s41598-020-64361-1.