Bronchial Atresia



Bronchial Atresia


Jud W. Gurney, MD, FACR










Coronal graphic shows bronchial atresia image with branching bronchocele image in the apical segment left upper lobe.






Coronal CECT shows focal lucency image from bronchial atresia and central mucus-filled bronchocele image in this patient with segmental bronchial atresia.


TERMINOLOGY


Abbreviations and Synonyms



  • Mucocele


Definitions



  • Congenital atresia of segmental bronchus with normal distal architecture


IMAGING FINDINGS


General Features



  • Best diagnostic clue: Round, sharply-defined, perihilar mass with distal hyperinflation


  • Patient position/location



    • Apicoposterior segment left upper lobe (50%)



      • Followed by right upper lobe (20%), lower lobes (15% each) and rarely right middle lobe (< 5%)


  • Size: Bronchocele usually > 1 cm in diameter


  • Morphology: Atretic bronchus usually segmental but may be lobar or distally in subsegmental airways


CT Findings



  • Triad: Bronchocele and hyperlucent and hypoperfused segment diagnostic of bronchial atresia


  • Bronchocele



    • May be of lower attenuation due to mucoid material


    • May contain calcium


    • No enhancement


    • Shape: Tubular, spherical, branching


    • Bronchocele aligned along central axis of affected segment


    • Bronchocele located medial to hyperinflated lung


    • Wedge-shaped hyperinflated lung surrounds bronchocele


  • Rare systemic arterial supply (bronchoarterial malinosculation)


Radiographic Findings



  • Radiography



    • Typical triad



      • Central nodule or mass representing mucoid impaction distal to atretic bronchus (bronchocele)


      • Hyperlucency of affected segment



      • Hypoperfusion of affected segment with paucity of vessels


    • Bronchocele



      • Sharply defined rounded or tubular branching opacities adjacent to the hilum (teardrops, grape-like clusters, gloved-finger appearance)


      • Bronchocele points towards hilum


      • Blunt horn-like protrusions distal to mass (mucoid impaction in bronchiectatic bronchi)


      • Occasionally have air-fluid level


    • Hyperlucent lobe



      • Neonates: Lobe or segment distal to atretic bronchus fluid-filled, gradually replaced by air


      • Resorption of fluid occurs within 1st week of life


      • Ventilation from collateral air drift via intraalveolar pores of Kohn and bronchoalveolar channels of Lambert across incomplete intrapulmonary fissures


    • Boomerang sign



      • Parabolic curve: Junction of hyperinflated segment with adjacent normal lung


    • Associated findings



      • Hypoplastic ribs, pectus excavatum


Ultrasonographic Findings



  • Can be detected in utero


  • Fluid-filled upper lobe



    • Differential



      • Cystic adenomatoid malformation


      • Congenital diaphragmatic hernia


      • Bronchopulmonary foregut malformations


      • Congenital lobar emphysema


Nuclear Medicine Findings



  • V/Q scan



    • Hypoperfusion of affected segment


    • Delayed ventilation of affected segment with delayed washout (air-trapping)


Imaging Recommendations



  • Best imaging tool: CT procedure of choice to characterize bronchocele, airway anatomy, and distal hyperinflated lung and other associated anomalies


  • Protocol advice



    • Expiratory CT demonstrates accentuated hyperinflation of affected segments


    • Multidetector CT useful in demonstrating anatomy of atretic bronchus


DIFFERENTIAL DIAGNOSIS


Mucoid Impaction with Hyperinflation



  • Bronchial atresia


  • Intralobar sequestration


  • Intrapulmonary bronchogenic cyst


Congenital Lobar Emphysema



  • No bronchocele


  • Left upper lobe also most commonly affected


  • Hyperinflated lobe causes mass effect with shift of mediastinum away from affected lobe


  • Usually diagnosed in infancy with respiratory distress


Intralobar Pulmonary Sequestration



  • May have distal hyperinflation


  • Abnormal systemic arterial supply, usually from aorta


  • Most common location is left lower lobe in paravertebral angle


Intrapulmonary Bronchogenic Cyst



  • Usually located in medial 1/3 of lung in lower lobes


  • May have distal hyperinflation


  • Cyst may be fluid-filled, air-filled, or both (air-fluid level)


Arteriovenous Malformation



  • Abnormal feeding artery and draining vein


  • Nodule will enhance with contrast administration


  • No bronchial obstruction, no hyperlucency or hyperinflation


Mucoid Impaction Associated Conditions



  • Endobronchial lesion



    • Bronchogenic carcinoma


    • Extrinsic compression


    • Foreign body



  • Inflammatory



    • Tuberculosis


    • Cystic fibrosis


    • Asthma


    • Allergic bronchopulmonary aspergillosis


Allergic Bronchopulmonary Aspergillosis



  • Central bronchiectasis with mucoid impaction


  • Diffuse, not localized


  • Primarily affects upper lung zones


  • Distal lung usually abnormal



    • Small airways disease: Tubular branching opacities, hyperinflation


Cystic Fibrosis

Sep 20, 2016 | Posted by in RESPIRATORY IMAGING | Comments Off on Bronchial Atresia
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