Atelectasis Radiology Report by Dr. Gian Hao

AtelectasisGiankarlo Hao MD

Definition:

• Ateles (incomplete) and ektasis (stretching)

• Loss of lung volume

• Collapse is often used synonymously with atelectasis it should be reserved for complete atelectasis

Physiologic Division of Atelectasis

Obstructive Non- obstructive

most common type

results from reabsorption of gas from the alveoli when communication between the alveoli and the trachea is obstructed.

caused by loss of contact between the parietal and visceral pleurae, compression, loss of surfactant, and replacement of parenchymal tissue by scarring or infiltrative disease

Mechanisms of Atelectasis

Resorptive (obstructive)

Passive (compressive)

Adhesive (subsegmental)

Cicatrization (scarring)



General considerations:

Air will disappear from healthy,obstructed lobe in 18-24 hours

Oxygen much more readily absorbedthan air

Will become apparent within an hour if highpO2

Bronchogenic carcinoma

Bronchial obstruction from metastatic neoplasm

Inflammatory etiology (eg, tuberculosis, fungal infection)

Aspirated foreign body

Mucous plug

Malpositioned endotracheal tube

Extrinsic compression of an airway by neoplasm, lymphadenopathy, aortic aneurysm, or cardiac enlargement






Collapse 2° space-occupying lesion• Pneumothorax• Hydrothorax

Density of the collapsed lung doesn’tincrease until lung reaches 1/10 normalvolume

>Air bronchograms may be seenbecause bronchi do not collapse

>Round atelectasis is form of passiveatelectasis






surfactant deficiency

Seen in patients:

• Are post-op• Have closed chest trauma• Have pleuritic chest pain






Underlying pathology is fibrosis

Localized form• Characterized by scarring in the upper lobefrom TB

Generalized form• May occur in diffuse interstitial fibrosis

Indirect

Radiologic Signs of Atelectasis

Direct Displacement of interlobar fissures

Crowding of vessels and bronchi (“crowded air-bronchogram”)

Indirect

Radiologic Signs of Atelectasis

Direct Displacement of interlobar fissures

Crowding of vessels and bronchi (“crowded air-bronchogram”)

Local opacityDiaphragmatic elevationMediastinal shiftApproximation of ribsCompensatory overinflationDisplacement of the hilumAbsence of an air bronchogramMiscellaneous signs: shifting granuloma/mass

Patterns of Atelectasis

Total Pulmonary Atelectasis

Lobar Atelectasis

Combined Lobar Atelectasis

Segmental Atelectasis

Linear (Plate-like) Atelectasis



Lobar Atelectasis




Mediastinum most affected

• Mediastinal shift toward the side of atelectasis

elevation of the hemidiaphragm

Usually secondary to obstruction of the main bronchus



Lobar Atelectasis




RUL Atelectasis

> Collapsed RUL shifts medially and superiorly elevation of the right hilum and the minor fissure> Tenting of the diaphragmatic pleura juxtaphrenic peak

RUL Atelectasis

> Collapsed RUL shifts medially and superiorly elevation of the right hilum and the minor fissure> Tenting of the diaphragmatic pleura juxtaphrenic peak


Lobar Atelectasis

LUL Atelectasis Major fissure moves forward• Superior segment of lower lobe creeps over apical segment“Luftsichel” (air crescent) sign

LUL Atelectasis

LATERAL: forward and medial displacement of the major fissureBroad linear opacity contiguous and parallel to the anterior chest wall


Lobar Atelectasis

LUL Atelectasis

LATERAL: forward and medial displacement of the major fissureBroad linear opacity contiguous and parallel to the anterior chest wall

Lobar Atelectasis


RML Atelectasis Easy on lateral Most difficult on PA

> Approximation of the lower half of major fissure and minor fissure> Obliteration of right cadiac border (silhouette sign)

Lobar Atelectasis


RML Atelectasis Easy on lateral Most difficult on PA

> Approximation of the lower half of major fissure and minor fissure> Obliteration of right cadiac border (silhouette sign)

Lingular Atelectasis

Basically follows the same pattern as RML atelectasis



Lobar Atelectasis






RUL – RML AtelectasisRML – RLL AtelectasisRUL – RLL Atelectasis

** Silhoutte sign

Homogenous opacity conforms to the anatomic distribution of a bronchopulmonary segment

Common in post op patients



Homogenous opacity conforms to the anatomic distribution of a bronchopulmonary segment

Common in post op patients

Segmental AtelectasisLinear (Plate-like) Atelectasis

Plate-like / Discoid Atelectasis, Fleischner lines

1-3 mm in thickness, 4-10 cm in length

Associated with diminished diaphragmatic excursion

“You will not grow if you sit in a beautiful flower garden, but you will if you are sick, in pain, experience losses and if you do not put your head in the sand but take the pain and learn to accept it, not as a curse or punishment but as a gift to you with a very, very specific purpose.”

Atelectasis Radiology Report by Dr. Gian Hao

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