A 60-year-old woman with rheumatoid arthritis presents with a flu-like illness and nonproductive cough. Her symptoms have not responded to an appropriate course of antibiotics. An HRCT is performed and demonstrates widespread mosaic perfusion. Which additional CT finding would suggest a diagnosis of obliterative bronchiolitis rather than diffuse pulmonary haemorrhage?
Increased calibre pulmonary vessels in the hyperattenuated area
Increased calibre pulmonary vessels in the hypoattenuated area
Normal calibre pulmonary vessels in the hyperattenuated area
Reduced calibre pulmonary vessels in the hypoattenuated area
Obliterative bronchiolitis describes bronchiolar and peribronchiolar inflammation affecting the membranous and respiratory bronchioles. Affected areas display decreased attenuation as a result of air trapping and decreased perfusion relative to normal areas.