Centrilobular pulmonary emphysema
Centrilobular pulmonary emphysema is the most common morphological subtype of pulmonary emphysema.
It may be found in up to one-half of adult smokers at autopsy 1.
The pathological process of centrilobular emphysema typically begins near the center of the secondary pulmonary lobule in the region of the proximal respiratory bronchiole. Selective lung destruction results in the characteristic apposition of normal and emphysematous lung. The resulting area of destruction surrounded by normal tissue allows appreciation of key structural lesion evident to the naked eye ”emphysematous space".
- cigarette smoking
- there is usually an upper lobe predilection
HRCT - CT chest
Early centrilobular emphysema is usually seen as small round black (low attenuating) evenly distributed holes with ill defined borders that may appear in the central portion of the secondary pulmonary nodule around the centrilobular artery.
As emphysematous process progresses, the low-attenuation areas become confluent and inseparable.
With enlargement of the dilated airspace, the surrounding lung parenchyma is compressed, which enables observation of a clear border between the emphysematous area and the normal lung. Since the disease progresses from the centrilobular portion, normal lung parenchyma in the perilobular portion tends to be preserved 2.
The pulmonary vessels in areas of severe emphysema are small, with shunting of blood flow to lung parenchyma that can better exchange air to maintain matched ventilation and perfusion.