Emphysema: Imaging for Endoscopic Lung Volume Reduction.

UNLABELLED: Chronic obstructive pulmonary disease (COPD) is characterized by two entities, the more airway-predominant type ("bronchitis") on the one hand, and emphysema-predominant type on the other. Imaging via high-resolution computed tomography plays an important role in phenotyping COPD. For patients with advanced lung emphysema, new endoscopic lung volume reduction therapies (ELVR) have been developed. Proper selection of suitable patients requires thin-section reconstruction of volumetric CT image data sets also in coronal and sagittal orientation are required. In the current manuscript we will describe emphysema subtypes (centrilobular, paraseptal, panlobular), options for quantifying emphysema and this importance of regional distribution (homogeneous or heterogeneous, target area) as this is crucial for patient selection. Analysis of the interlobular fissures is obligatory despite the lack of standardization, as incomplete fissures indicate collateral ventilation (CV) via parenchymal bridges, which is an important criterion in choosing endoscopic methods of LVR. Every radiologist should be familiar with modern LVR therapies such as valves and coils, and furthermore should know what a lung doctor expects from radiologic evaluation (before and after ELVR). Finally we present a checklist as a quick reference for all steps concerning imaging for ELVR.

KEY POINTS: • High-resolution computed tomography with 3 D reconstructions becomes increasingly important in phenotyping COPD and diagnosing emphysema. • Patient selection is crucial for modern techniques of lung volume reduction, such as valves or coils. • Radiology plays a key role for fissural analysis and identifying a target area. • Success of this therapy depends on experience and multidisciplinary cooperation.