Medical Imaging

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.

Review Densities

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 – 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

Effusion - Fluid Pooling