Emphysema, Centrilobular



Emphysema, Centrilobular


Jud W. Gurney, MD, FACR










Axial HRCT shows low-attenuation foci of centrilobular emphysema within the outlines of a secondary pulmonary lobule image.






Gross pathology shows early centrilobular emphysema image from the destruction of a respiratory bronchiole. The septa image outline the edge of the secondary pulmonary lobule.


TERMINOLOGY


Abbreviations and Synonyms



  • Centrilobular emphysema (CLE), centriacinar emphysema (CAE), chronic obstructive pulmonary disease (COPD), proximal acinar emphysema, vanishing lung


Definitions



  • Emphysema: Abnormal permanent enlargement of any or all parts of acinus, accompanied by destruction of alveolar tissue but without fibrosis



    • CLE: Enlargement and destruction of respiratory bronchioles within secondary pulmonary lobule (SPL)


  • COPD: Presence of airflow obstruction caused by chronic bronchitis or emphysema



    • Airflow obstruction is generally progressive; may be accompanied by airway hyper-reactivity and may be partially reversible


    • Includes asthma, chronic bronchitis, emphysema, and bronchiectasis


    • CLE most common form of emphysema associated with symptomatic or fatal chronic airway obstruction


IMAGING FINDINGS


General Features



  • Best diagnostic clue: Well-defined holes in centrilobular portion of SPL


  • Patient position/location: Predominantly involves upper lung zones


CT Findings



  • Morphology



    • Small localized rounded areas of low attenuation within centrilobular region of SPL


    • Centrilobular artery may be identified in emphysematous lung


    • Wall is indiscernible; thin walls may be seen in larger emphysematous spaces, probably secondary to relaxation atelectasis of adjacent lung


    • Borders of SPL are preserved in mild disease


    • Bulla: Emphysematous space, commonly subpleural, > 1 cm diameter



  • Distribution



    • Upper lung zones show predominant disease


    • Axial plane: CLE more severe centrally than in peripheral lung


  • Quantification of extent of emphysema either subjective or objective



    • Subjective usually sufficient for clinical practice


  • Subjective visual grading



    • Normal, trivial (< 5% lung affected)


    • Mild emphysema (5-25%), moderate (26-50%), marked (51-75%), severe (> 75%)


  • Objective: Pixel density (density mask)

Sep 20, 2016 | Posted by in RESPIRATORY IMAGING | Comments Off on Emphysema, Centrilobular
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