COLLAPSE AND CONSOLIDATION OF

LUNGSDr Neelam AsharNishtar hospital Radiology Department

•Collapse is diminished

volume of air in the lung with associated reduction of lung volume and in consolidation there is diminished volume of air in the lung associated with normal lung volume

• MECHANISMS OF COLLAPSE

• 1)Relaxation or passive collapse

• 2)Cicatrization collapse

• 3)Adhesive collapse

• 4)Resorrption collapse

RADIOLOGICAL SIGNS OF COLLAPSE

• Direct signs of collapse• 1)Displacement of interlobar fissure

• 2)Loss of aeration

• 3)Vascular and bronchial signs

• Indirect signs of collapse• 1)Elevation of hemidiaphragm

• 2)Mediastinal displacement

• 3)Hilar displacement

• 4)Compensatory hyperinflation

• Patterns of lung collapse• 1)Complete collapse of a lung

• 2)Lobar collapse

1)COMPLETE COLLAPSE

• Causes opaque hemithorax with displacement of mediastinum to the affected side with compensatory hyperinflation of opposite lung often with herniation across midline.

• Herniation mostly occurs in retrosternal space but may occur posterior to heart or under aortic arch

LOBAR COLLAPSE

•RUL collapse• Horizontal fissure displaced upward,The

upper half of oblique fissure moves anteriorly.

• Hilum is elevated

• Tracheal deviation to right• Compensatory hyperinflation of right middle

and lower lobes may be seen

RUL collapse

• Golden‘s (reverse S) sign. a. Chest X-ray of a patient with a centrally located mass. The reverse S sign due to right upper lobe atelectasis is clearly depicted. The lateral portion of the ‘S’ is formed by the superiorly displaced minor fissure and the medial portion by the mass (arrows). b. Golden S.

• Juxtaphrenic peak sign• The juxtaphrenic peak sign, which occurs in upper lobe

atelectasis, describes the triangular opacity projecting superiorly at the medial half of the diaphragm (Fig. 13). It is most commonly related to the presence of an inferior accessory fissure[7]. The mechanism is not known with certainty; according to one theory, the negative pressure of upper lobe atelectasis causes upward retraction of the visceral pleura, and protrusion of extrapleural fat into the recess of the fissure is responsible[15]. The juxtaphrenic sign can also be seen in combined right upper and middle lobe volume loss or even with middle lobe collapse only.

• 2)RML collapse• Horizontal fissure and oblique fissure move

towards one another• Obscuration of right heart border• Lordotic AP projection best for middle lobe

collapse• Volume of this lobe is small so indirect signs

rarely present.

RML

increased opacity of lobeloss of visualisation of right heart borderright hemidiaphragm visualisation unaffectedairbronchogram (consolidation)

Posteroanterior (PA) (left) and lateral chest (right) radiographs. A right middle lobe collapse obliterates the

right heart border on the PA image and projects as a wedge-shaped opacity on the lateral view.

• 3)RLL collapse• Depression of horizontal fissure• Increase opacity of collapse lower lobe • In case of complete collapse of lower lobe it may

be so small that it merges with mediastinum and produce a thin wedge shape shadow.

• Mediastinal parts and adjacent diaphragm obscured

• Hila depressed• Diaphragm elevation is not usual

RLL

The lateral view is usually definitive- there will be postero-inferior movement of the oblique fissure whilst maintaining the same slopeThe lower lobes collapsedownwardmedially toward the spine andposteriorly

right lower lobe collapse that results in volume loss, obliteration of the right side of the diaphragm,

and a posterior opacity.

collapse on USG

• Sonography of the chest was done in this patient. Images reveal a large, clear, hypoechoic fluid collection in the left pleural space. The left lung has collapsed into a small mass of tissue compressed by the effusion. A small fibrotic band is seen traversing the fluid. These ultrasound images are diagnostic of pleuraleffusion

• 4)LUL collapse• Anterior displacement of entire oblique

fissure

• Ill defined hazy opacity in upper,mid and sometimes lower zone

• Hila elevated

• Aortic knuckle obscured.

• With increasing collapse upper lobe retracts posteriorly and loses contact with anterior chest wall.

• The space between the collapsed lung and sternum is occupied by either hyperinflatedleft lower lobe or herniated right upper lobe.

• When complete collapse occurs LUL lose contact with chest wall and diaphragm and retract medially against the mediastinum

• On lateral film therefore LUL collapse appears as an elongated opacity extending from apex and almost reaching diaphragm,anterior to hilum and is bounded by displaced oblique fissure posteriorly and by hyperinflated lower lobe anteriorly

• The lateral view is usually definitive and often highly characteristic.

• As the LUL collapses, the fissure moves forward pivoting at its lowest point

• The lateral view demonstrates the highly characteristic collapsed lobe which now lies parallel to the sternum

lul

• The PA view will show an area of increased opacity in the left upper lobe with an ill-defined margin.

• The PA view will shows an area of increased opacity in the left upper lobe with an ill-defined margin.

• Note the loss of the heart shadow/mediastinum and the mediastinal shift

• Luftsichel sign• The word “Luftsichel” in German means “air

crescent”. This sign is seen in severe left upper lobe collapse. Due to the lack of a minor fissure on the left side, upper lobe collapse causes vertical positioning and anterior and medial displacement of the major fissure. The superior segment of the left lower lobe migrates superior and anteriorly between the arch of the aorta and the atelectatic lobe. The crescent-shaped radiolucency around the aortic arch is called the Luftsichel sign

• Left upper lobe collapse. This radiograph shows an opacity that is contiguous with the aortic knob, a smaller left hemithorax, and a mediastinal shift. The luftsichel sign involves hyperextension of the superior segment of the left lower lobe, which then occupies the left apex

left upper lobe collapsing anteriorly

• 5)LINGULA COLLAPSE• often involved with LUL collapse may

collaspe alone

• Anterior displacement of lower half of oblique fissure

• Increase opacity

• Obscuration of left heart border

• LLL collapse• Oblique fissure moves posteriorly

• The PA view will show a triangular area of increased opacity behind the left heart shadow.

• There may be loss of visualisation of the left hemi-diaphragm behind the heart

• The lower lobes collapse• downward• medially toward the spine

and• posteriorly

• In the lateral view a triangular opacity will be seen at the base of the lung with a sharply defined anterior margin formed by the oblique fissure

left a lower lobe collapse. The opacity is in a posteroinferior location.

Computed tomography scan demonstrating rounded atelectasis in a patient exposed to asbestos. This image shows a peripheral pleural-based opacity with crowding of the bronchovascular structures in the

comet-tail sign.

CONSOLIDATION• Replacement of air in one or more acini by

fluid or solid material

• Smallest unit of consolidated lung is acinus casts 7mm diameter shadow

• Confluence occurs

• Causes of consolidationAcute inflammatory exudate like

pneumoniaCardiogenic pulmonary edemaNon cardiogenic pulmonary edemaHemorrhageAspirationAlveolar cell carcinomaAlveloar proteinosis

• When consolidation is associated with

patent conducting airway an air bronchogram seen.It is produced by contrast between the column of air in the airway and surrounding opaque acini

• If consolidation is secondary to bronchial obstruction affected area is of unifrorm density with no air bronchograms.

• VOLUME OF THE LUNG IS NORMAL UNLIKE COLLAPSE

• RUL consolidationConfined by horizontal fissure inferiorly and upper half of oblique fissure posteriorly ,may obscue right upper mediastinum

• RML consolidation• limited by horizontal fissure

above and lower half of obliue fissure posteriorly ,may obscure right heart border

• Lower lobe consolidation• It is limited by oblique fissure anteriorly

and may obscure diaphragm

• LUL and lingula consolidation• These are limited by oblique fissure

posteriorly ,lingular consolidation may obscure left heart border,consolidation of upper lobe may obscure aortic knuckle.

rul consolidation

lingular consolidation

RLL consolidation

• Air bronchogram sign. a. Chest X-ray of a patient who had radiotherapy for breast cancer. Consolidation with air bronchograms (arrows) due to radiation pneumonitis at the upper lobe of the right lung. b. Air bronchogram sign on CT. c. Illustration of air bronchogram sign.

USG consolidation• Sonography of the left lung reveals

loss of normal aeration of the lung parenchyma with echogencity and texture similar to that of the spleen below. The echogenic left dome of diaphragm is seen separating the lower lobe of the lung from the spleen. The normal aerated lung surface would reflect all the sound waves producing a strong shadow. These ultrasound images suggest consolidation of the lung. Image courtesy of Dr. Gunjan Puri, Surat, India. Image taken using a Toshiba Xario, ultrasound and color doppler machine.

OPACITY WITH AIR BRONCHGRAMS