Presentation
Chronic smoker with ischemic heart disease and severe tricuspid regurgitation.
Patient Data
HRCT shows bilateral upper lobe paraseptal emphysema. Homogenous ground-glass opacity; bilateral and fairly symmetric with a peribronchovascular distribution. Bilateral subpleural and peribronchovascular reticulation with traction bronchiectasis. No honeycombing. The lung volumes are preserved. Pulmonary artery is dilated and there is cardiomegaly.
Case Discussion
The exact radiographic features of hypersensitivity pneumonitis (HP) depend on subtypes (acute/inflammatory or chronic/fibrotic).
HRCT features for acute onset include diffuse ground-glass opacities (GGO), centrilobular nodules, air trapping and head cheese sign.
The chronic features are reticulation, peribronchovascular interstitial thickening, architectural distortion, honeycombing, air trapping, and ill-defined centrilobular GGO.
The radiographic findings may mimic those of UIP or NSIP. In such cases, the CT findings that are most suggestive of HP are centrilobular opacities and air trapping.