Abstract
Purpose: To assess the ability of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to quantify pulmonary capillary permeability, leakage space and blood volume in asthmatic patients.
Methods: Consenting volunteers (10 healthy, 20 asthmatic) underwent pulmonary function tests and DCE-MRI at 1.5 Tesla within 7 days. The extended Kety model was fitted to the contrast agent concentration-time curves to extract transfer constant (Ktrans), fractional leakage volume (ve) and the fractional blood plasma volume (vp). Parameters were summarized using median values over the lungs.
Results: Median ve was significantly higher in asthmatics (0.30 ± 0.06 ml/ml tissue) than in healthy subjects (0.23 ± 0.02 ml/ml tissue, P = 0.001) but was not different between mild and severe asthmatics, indicating the increased extravascular leakage space in asthmatic lungs. While median Ktrans did not differ between patients and healthy subjects, there was a difference between mild and severe asthmatics (0.19 ± 0.07 vs 0.28 ± 0.07 ml/min/ml tissue, P = 0.040), implying increased vascular permeability and/or blood flow in more severe disease. Median vp was not different between groups.
Conclusion: Quantitative DCE-MRI parameters are promising biomarkers of pulmonary inflammation in asthma, with ve sensitive to the presence of asthma and Ktrans sensitive to asthma severity.
Acknowledgement: Dorothy Hodgkin Postgraduate Award from AstraZeneca and RCUK for funds.
- © 2014 ERS