Radiological Features of Pulmonary Emphysema and Fibrosis

Pulmonary Emphysema

Emphysema appears as areas of decreased attenuation without visible walls, representing destruction of alveolar walls, and is characterized by reduced lung markings and hyperinflation 1
Visual scoring of emphysema is used to determine whether it spans ≥15% of total lung volume, which is associated with increased risk of complications 1

Fibrosis is confidently recognized when traction bronchiectasis/bronchiolectasis and/or honeycombing are identified, and predominantly affects basal and subpleural regions of the lungs 2
Key findings include honeycombing, traction bronchiectasis, and reticular opacities, which represent end-stage fibrosis and fibrotic thickening of interlobular septa 2
Ground-glass opacities, when associated with architectural distortion, suggest active inflammation or fine fibrosis 1, 2

High-resolution CT (HRCT) is the diagnostic procedure of choice for both conditions, and multi-planar reconstruction on sagittal and coronal planes should be evaluated to increase diagnostic confidence 1, 3
For fibrosis assessment, the extent is determined by visually estimating the percentage of parenchymal involvement 1

The presence of traction bronchiectasis in a probable UIP pattern on HRCT increases the likelihood of IPF diagnosis 3
Extent of emphysema >15% must be reported as it is associated with comorbidities and disease progression 1
The UIP pattern is a hallmark of IPF but can also be seen in fibrotic hypersensitivity pneumonitis and connective tissue disease 2
Identification of the correct pattern guides treatment decisions: antifibrotic therapy for fibrosis versus bronchodilators for emphysema 4