Unilateral hypertransradiant hemithorax (mnemonic)

Unilateral hypertransradiancy is the correct term for the chest radiograph appearance of increased blackness affecting one lung. Hyperlucency is a commonly used alternative but is inaccurate; the chest is not penetrated by light!

A logical approach begins by checking for:

• technical factors

• patient rotation

• chest wall abnormalities

• ipsilateral pneumothorax

• contralateral pleural opacity

• primary decrease in lung perfusion

• secondary decrease in lung perfusion due to air-trapping

Mnemonics for a unilateral hypertransradiant hemithorax include:

• CRAWLS

• SAFE POEM

• ACROSSS

Mnemonics

CRAWLS

• C: contralateral lung increased density (e.g. supine pleural effusion)

• R: rotation

• A: air (pneumothorax)

• W: wall (chest wall mass, mastectomy, polio, Poland syndrome, surgical removal of the pectoralis major muscle)

• L: lungs (airway obstruction, emphysema, Swyer-James syndrome, unilateral large bullae, large pulmonary embolus)

• S: scoliosis

SAFE POEM

• S: Swyer-James syndrome

• A: agenesis (pulmonary)

• F: fibrosis (mediastinal)

• E: effusion (pleural effusion on the contralateral side) 

• P: pneumonectomy/pneumothorax 

• O: obstruction (airway)

• E: embolus (pulmonary)

• M: mucous plug

ACROSSS

• A: air (pneumothorax), artery (pulmonary aplasia or hypoplasia)

• C: chest wall (mastectomy, polio, Poland syndrome)

• R: rotation

• O: obstructive causes (airway obstruction, foreign body, unilateral emphysema, large embolus)

• S: scoliosis

• S: surrounding (increased density in contralateral lung, e.g. pleural effusion in the opposite lung in a recumbent patient)

• S: Swyer-James syndrome

See also

• unilateral hyperlucent hemithorax