Left Lower Lobe – Anatomy
Review Densities
Compare Tissue Attenuation
On x-rays because air is less dense and therefore shows up radiolucent (black), increasing amounts of soft tissue or less air shows up more radio-opaque or white. Similarly a “line” on an x-ray signifies air is present on both sides of the line, while an “interface” describes a separation of structures of differing densities.
Pneumothorax – Sulcus Sign
2. Evaluate for Pneumothorax – Sulcus Sign
Left Image: Depicts the deep sulcus sign.
Right Image: Lateral decubitis view of the pneumothorax. The pleural air will rise above the lung in this view.
Pneumothorax – Mediastinal Shift
3. Evaluate for Pneumothorax – Mediastinal Shift
Large pleural effusions may cause a mass effect, shifting the mediastinum and trachea to the opposite side, and/or causing atelectasis of the adjacent lung.
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Pneumothorax – Lung and Air Contrast
1. Evaulate for Pneumothorax – Lung/Air Contrast
A pneumothorax allows visualization of the viscerla pleura as a curvilinear line, paralleling the chest wall, separating the partially collapsed lung from pleural air.
Left Image: Pneumothorax on inspiration.
Right Image: Pneumothorax on expiration.
Parietal and Visceral Pleura
Identify: Parietal & Visceral Pleura
The Pleura lubricates and prevents friction during respiration.
The partial pleura lines the chest wall, mediastinal and diaphragmatic surfaces, while the visceral pleura lines the lungs and fissures.
Evaluate for Appearance
Evaluate for Appearance – Thickening
Thickening of the pleura is usually a result of inflammation.
Evaluate for Appearance – Calcifications
Calcification is a result of a previous emphysema or pneumothorax.
Evaluate for Appearance – Mass
Pleural and extra pleural masses form an obtuse angle with adjacent pleura, while parenchymal and pulmonary masses usually form an actue angle
Effusion Mediastinal Shift
4. Evaluate for Effusion Mediastinal Shift
A mediastinal shift can occur if there is tension. In this image, notice the collapsed right lung. This patient requires a chest tube to relieve the pressure.
Effusion – Meniscus
1. Evaulate for Effusion – Meniscus
In an uncomplicated effusion, fluid is usually higher laterally than medially, thus forming a meniscus with the pleura. A horizontal fluid line will be seen only with a mixture of air and water in the pleura space (hydropneumothorax).
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Effusion – Fluid Pooling
3. Evaluate for Effusion – Fluid Pooling
Pooling of fluid can first be seen posteriorly. If there is enough it will then move laterally.
This is why the lateral film is most sensitive for pleural effusion. A lateral decubitis view will show the effusion in a dependent position if it is not loculated.
Right image depicts a lateral decubitis view with a small effusion
