Related Experiment Video
Updated: Dec 12, 2025
Multi-modal Pulmonary Imaging: Using Complementary Information from CT and Hyperpolarized 129Xe MRI to Evaluate Lung Structure-Function
Published on: April 12, 2024
Emphysema Index Based on Hyperpolarized 3He or 129Xe Diffusion MRI: Performance and Comparison with Quantitative CT
Sina Tafti1, William J Garrison1, John P Mugler1
1From the Departments of Physics (S.T., G.D.C.), Biomedical Engineering (W.J.G., J.P.M., G.W.M.), Radiology and Medical Imaging (J.P.M., J.F.M., E.E.d.L., A.M.R., G.W.M.), and Medicine (Y.M.S.), University of Virginia, Box 801339, Charlottesville, VA 22908; Department of Radiology, University of Missouri, Columbia, Mo (T.A.A.); and Department of Science and Engineering, University of Nottingham, Ningbo, China (C.W.).
A new emphysema index using hyperpolarized gas MRI offers a repeatable and accurate method for assessing emphysema burden in COPD patients. This quantitative metric shows diagnostic performance comparable to CT scans and pulmonary function tests.
Area of Science:
- Radiology
- Pulmonary Medicine
- Medical Imaging
Background:
- Apparent diffusion coefficient (ADC) maps from hyperpolarized gas MRI show potential for emphysema characterization in COPD.
- A need exists for a quantitative metric beyond mean and standard deviation for emphysema assessment.
- Current methods lack easily interpretable quantitative measures for emphysema burden.
Purpose of the Study:
- Introduce a quantitative framework to characterize emphysema burden using hyperpolarized helium-3 (3He) and xenon-129 (129Xe) ADC maps.
- Compare the diagnostic performance of this new ADC-based metric with CT-based emphysema metrics and pulmonary function tests (PFTs).
Main Methods:
- Retrospective study of 27 COPD patients and 13 healthy controls.
- Acquired CT, 3He and 129Xe MRI (multiple b values), and PFTs.
- Computed ADC-based emphysema index as the fraction of lung voxels with ADC values exceeding the healthy 99th percentile.
Main Results:
- ADC-based emphysema index demonstrated high repeatability (ICC > 0.99).
- Strong correlations were found between ADC index and quantitative CT (r=0.86 for 3He, r=0.85 for 129Xe).
- High diagnostic performance (AUC ≥ 0.93) and correlations with PFTs (e.g., DLCO, RV/TLC) were observed.
Conclusions:
- Emphysema index derived from hyperpolarized gas diffusion MRI is a repeatable measure of emphysema burden.
- This metric is independent of the specific gas (3He or 129Xe) or b value used.
- Diagnostic performance is comparable to quantitative CT and pulmonary function metrics.
