Mod 3 - chest radiography

indications for CXR

• to detect alterations in lungs caused by pathologic processes

• to determine appropriate therapy

• to determine position of tubes &/or catheters

• to observe progress of lung disease

indications for chest CT

• evaluation of nodules &/or masses

• fluid collection

• vascular disease

• airway disease

chest MRI

pretty poor image of lungs

• vascular imaging

• mediastinal masses

• chest wall masses

• spine & neurological masses 

CXR positioning & routine views

• posterior-anterior projection

• left lateral decubitus 

• supine AP view

basic X-ray principles

• dense objects block rays → whiteness on film

• less dense objects let rays through → dark on film

• objects closer to film appear sharper

• silhouette sign

  • when 2 structures of the same density are adjacent to e/o

  • border b/w them is lost

5 basic densities on X-ray

darkest to whitest

1. air

2. fat

3. soft tissue & fluids

4. bone

5. metal

CXR evaluation criteria

• sternum equal distance from vertebral column

• trachea @ midline

• scaps positioned outside lung field

• costophrenic angles

reading CXR

• PA is gold standard

• penetration

  • look @ intervertebral discs & spinous processes

• inspiration

  • count ribs (should see 8-10 posterior ribs w/ good inspiration)

• rotation

  • spinous processes should be equidistant from medial ends of clavicles

• diaphragm

  • trace cardiophrenic & costophrenic angles

    • should be sharp w/ no air under diaphragm

• lung fields

  • opacities, fissures blood vessels

  • compare R to L

• bones

• mediastinal structures