A brief look at the lateral CXR Key points• There should be adecrease in densityfrom superior toinferior in theposterior mediastinum.• The retrosternalairspace should beof the same densityas the retrocardiacairspace.
Identify the oblique fissure• (pass obliquely downwards from the T4/T5 vertebrae through the hilum ending at the anterior third of the diaphragm)
Identify the horizontal fissure• (pass horizontally from the midpoint of the hilum to the anterior chest wall)
If the lesion lies posterior to the oblique fissure it must lie within the lower lobe
If the lesion lies anterior to the oblique fissure it may be in the upper or middle lobe
If the lesion is below the horizontal fissure it is in the middle lobe
If the lesion is above the horizontal fissure it is in the upper lobe
POSITION PA AP QUALITY ROTATION PENETRATION INSPIRATION LESION Homo HeterogenousDensityinfiltration necrotic Zone Centralperipheral Silhouet sign MEDIASTINAL Central deviasionwided COSTO-PHRENIC ANGEL Freeoblitern OTHER Bone soft tissuediaphragm
POSITION •AP CXRQUALITY •Poor Technical Quality •homogeneous density in the right upper zoneLESION , elevation of the transverse fissure •Central trachea and mediasteinalMEDIASTINAL •Free costo-phrenic angelsANGELS •NOOTHER
S sign• homogeneous density in the right upper zone• elevation of the transverse fissure ( Instead of the transverse fissure being straight)• there is a bulge at the medial end giving it an inverted S shape.• Golden described this sign and the explanation for it is that the upper lobe collapse is due to a right hilar mass which accounts for the medial bulge
Homogenous Atelectasis Right Upper Lobe density right upper lung field.Mediastinal shift to right.Loss of silhouette of ascending aorta.Movement of oblique and transverse fissures.
POSITION •PA CXRQUALITY •Poor Technical Quality •(poor penetration). •hazy, veil-like opacificationLESION •in the left upper zone,obscured aortic arc,from hilar to peripheral •Central trachea and mediasteinalMEDIASTINAL •Obscured left costo-phrenic angelsANGELS •Elevate left hemidiaphragm •NOOTHER
Illustration• The CXR shows evidence of left upper lobe collapse.• There is a hazy, veil-like opacification in the left upper lobe, which does not have a sharp inferior margin unlike right upper lobe collapse.• This is because there is usually no left transverse fissure and the lobe collapses anteriorly..• There is also volume loss in the left hemithorax as evidenced by an elevated left hemidiaphragm and crowding of the left upper ribs.• Sometimes the trachea may also be deviated to the same side and the aortic knuckle may be obscured by the collapse
Mediastinal shift to left.Density left upper lung field.Loss of aortic knob and left hilar silhouettes. Atelectasis Left Upper Lobe
A:Forwardmovementof obliquefissureC:AtelectaticLULB:Herniatedright lung Atelectasis Left Upper Lobe
Bowing sign•LUL atelectasis or following resection•The oblique fissure bows forwards