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Updated: Dec 29, 2025
Quantitative Mapping of Specific Ventilation in the Human Lung using Proton Magnetic Resonance Imaging and Oxygen as a Contrast Agent
Published on: June 5, 2019
Relative Regional Air Volume Change Maps at the Acinar Scale Reflect Variable Ventilation in Low Lung Attenuation of
Kum Ju Chae1, Jiwoong Choi2, Gong Yong Jin1
1Department of Radiology, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, South Korea.
Objectives:
The purpose of this study was to investigate regional air volume changes at the acinar scale of the lung in chronic obstructive pulmonary disease (COPD) patients using an image registration technique.
Materials And Methods:
Thirty-four emphysema patients and 24 subjects with normal chest CT and pulmonary function test (PFT) results were included in this retrospective study for which informed consent was waived by the institutional review board. After lung segmentation, a mass-preserving image registration technique was used to compute relative regional air volume changes (RRAVCs) between inspiration and expiration CT scans. After determining the appropriate thresholds of RRAVCs for low ventilation areas (LVAs), they were displayed and analyzed using color maps on the background inspiration CT image, and compared with the low attenuation area (LAA) map. Correlations between quantitative CT parameters and PFTs were assessed using Pearson's correlation test, and parameters were compared between emphysema and normal-CT patients using the Student's t-test.
Results:
LVA percentage with an RRAVC threshold of 0.5 (%LVA0.5) showed the strongest correlations with FEV1/FVC (r = -0.566), FEV1 (r = -0.534), %LAA-950insp (r = 0.712), and %LAA-856exp (r = 0.775). %LVA0.5 was significantly higher (P < 0.001) in COPD patients than normal subjects. Despite the identical appearance of emphysematous lesions on the LAA-950insp map, the RRAVC map depicted a wide range of ventilation differences between these LAA clusters.
Conclusion:
RRAVC-based %LVA0.5 correlated well with FEV1/FVC, FEV1, %LAA-950insp and %LAA-856exp. RRAVC holds the potential for providing additional acinar scale functional information for emphysematous LAAs in inspiratory CT images, providing the basis for a novel set for emphysematous phenotypes.
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