Characterizing chronic obstructive pulmonary disease using quantitative MRI biomarkers.

Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung disease that occurs due to structural changes to the parenchyma, airways and pulmonary vasculature, and consequent functional impairments to ventilation and perfusion. Although computed tomography (CT) imaging is the standard for assessing structural lung changes in COPD, it requires ionizing radiation and is unable to provide functional information without contrast agents. Conversely, there have been numerous developments for MRI of the lungs in the last several decades, allowing for the quantification of structural and functional abnormalities without ionizing radiation. Various quantitative MR (qMR) imaging biomarkers have been developed that describe parenchymal and airway structure as well as ventilation and perfusion within the lungs. These qMR imaging biomarkers have been investigated in individuals with COPD, reporting both cross-sectional and longitudinal associations with important outcomes. Therefore, the aim of this article is to briefly review some commonly used MRI techniques that have been investigated for lung imaging and discuss commonly implemented qMR imaging biomarkers and their application in COPD. Additionally, this review will focus on gaps in the literature that should be addressed to allow for future widespread implementation of qMR imaging biomarkers in COPD-related research.