The fourth pattern includes abnormalities that result in decreased lung attenuation or air-filled lesions. These include: - Emphysema - Lung cysts (LAM, LIP, Langerhans cell histiocytosis) - Bronchiectasis - Honeycombing Most diseases with a low attenuation pattern can be readily distinguished on the basis of HRCT findings. #Diagnosis #Radiology #Pulmonary #CTChest #LowAttenuation #Differential #Diagram #Comparison #Honeycombing #TractionBronchiectasis #Cysts #Emphysema #SignetRing #RadiologyAssistant
