What CT finding is characteristic of bronchiectasis?

What CT finding is characteristic of bronchiectasis?

• A. Ground-glass opacity
• B. Tram-tracking or signet ring sign
• C. Lobar collapse
• D. Interstitial edema

Answer: (B)

Bronchiectasis shows dilated airways with thick bronchial walls that fail to taper as they extend toward the periphery. On CT, the classic clues are a signet ring appearance and tram-tracking. The signet ring sign comes from a dilated bronchus seen beside its adjacent pulmonary artery, forming a ring-like image. Tram-tracking occurs when thickened, inflamed bronchial walls run parallel as linear densities on axial images. Together with a bronchoarterial ratio greater than one and lack of tapering, these findings are characteristic of bronchiectasis. Ground-glass opacity, lobar collapse, and interstitial edema point to other processes and don’t define bronchiectasis.

Bronchiectasis shows dilated airways with thick bronchial walls that fail to taper as they extend toward the periphery. On CT, the classic clues are a signet ring appearance and tram-tracking. The signet ring sign comes from a dilated bronchus seen beside its adjacent pulmonary artery, forming a ring-like image. Tram-tracking occurs when thickened, inflamed bronchial walls run parallel as linear densities on axial images. Together with a bronchoarterial ratio greater than one and lack of tapering, these findings are characteristic of bronchiectasis. Ground-glass opacity, lobar collapse, and interstitial edema point to other processes and don’t define bronchiectasis.