Longitudinal parametric response mapping on CT in assessing functional small airway disease and emphysema in COPD

This study evaluated the progression of functional small airway disease (fSAD) and emphysema in patients with COPD using longitudinal parametric response mapping (PRM) on CT. In 197 patients, analysis of baseline and follow-up CT scans demonstrated that both PRM-fSAD and PRM-emphysema increased over time. An increase in PRM-fSAD was significantly associated with a decline in FEV1, and higher baseline PRM-fSAD values predicted faster deterioration in lung function. In contrast, changes in PRM-emphysema were not significantly associated with lung function decline. CT images were analyzed and PRM maps were generated using AVIEWⓇ software (Coreline Soft). These findings suggest that longitudinal PRM is a valuable tool for monitoring COPD progression, with fSAD serving as a stronger predictor of lung function decline than emphysema.