Lobar Collapse

Lung Anatomy (1) aortic arch (2) pulmonary trunk (3) left atrial appendage (4) left ventricle (5) right atrium (6) superior vena cava (7 & 8) diaphragm (9) transverse fissure Transverse fissure – 6th rib laterally Does not estend beyond pulm artery medially Visible in 50%

Lung Anatomy (1) oblique fissure (2) transverse fissure (3) retrocardiac space (4) retrosternal space Oblique fissure from t4 posteriorly Propeller shaped Differentiation between sides- left is more vertical, has more posterior junction with the diaphragm= does not intersect transverse fissure Left diaphragm is lower and possesses stomach bubble by 2.5cm in 94% population

Lobar Extent T4 – upper portion faces forwards amd laterally Lower portion faces posteriorly and laterally

Lobar Extent

Silhouette Sign If two soft tissue densities lie in apposition, then they will not be visible separately If they are separated by air, the boundaries of both will be seen

Uses of Silhouette Localisation without a lateral view Loss of clarity of a structure suggests there is adjacent soft tissue shadowing even when the abnormality itself is not clearly visualised. This is particularly valuable in some cases of lobar collapse.

Lobar Collapse Partial or complete loss of lung volume Air resorption Atelectasis

Common causes of lobar collapse Proximal stenosing bronchogenic carcinoma. Middle aged or elderly, almost always smokers. Asthma due to mucous plugging Young adult or older child ,responds to physiotherapy. Inhaled foreign body Infants , such as a peanut. Retention of secretions Any age, frequent cause of post operative collapse. Ventilation Endotracheal tube is inserted too far, entering one main bronchus and occluding the other.

Signs of Lobar Collapse Shift of fissures Crowding of vessels (increased opacity) Extra lobar Hemi diaphragm elevation Mediastinal shift towards side of collapse Hilar shift and distortion Compensatory hyperinflation Rib approximation Shift of other structures e.g. granuloma

Right upper lobe collapse Minor fissure pivots and bows Right hilar elevation May simulate mediastinal widening Deviation of trachea Both fissures concave superiorly

Right upper lobe collapse

Golden’s S sign

Golden’s S sign

Right Lower lobe collapse Posterior and medial collapse Obliteration of the right hemi diaphragm Heart border clearly seen Transverse fissure pulled inferiorly

Right Lower lobe collapse

Right Middle Lobe Collapse Right horizontal and oblique fissure move towards each other often subtle blur the normally sharp right-heart border (silhouette sign)

Right Middle lobe Collapse

Left lower lobe collapse Posterior and medial collapse triangular opacity – sail sign hemidiaphragm may be obscured

Left Lower lobe collapse

Left Upper Lobe Collapse veil like opacity aortic knuckle, left hilum, and left-heart border initially ill defined but may progress to become sharp almost vertical oblique fissure

Left Upper Lobe Collapse

Left Upper Lobe Collapse ‘Luftsichel’

Complete Collapse

Summary Right Right Upper lobe Right middle lobe Right Lower Lobe

Summary Left Left upper lobe Left lower lobe