Chest X-ray

ID

• name
• age
• date
• modality

Marker

• Right or Left

Position

• Medial ends of the clavicles should be equidistant from the spinous processes at the midline to rule out rotation

Quality

• Penetration
  • thoracic disc spaces should be just visible through the heart
    • overexposure → too dark
    • underexposure → too white

Respiration

• good inspiration → 6th anterior, 10th posterior ribs at MCL
• right hemidiaphragm at 6th anterior rib
• poor inspiration:
  • poor aeration, vascular crowding, widened central shadow

Hardware

• Comment on any lines, lead placements, tubing, etc.

Bones

• C-spine, T-spine → alignment, disc space spacing, lytic or blastic lesions
• shoulder girdle, ribs, humerus, sternum → fractures, osteopenia, deformities
• vertebra OA (lateral view)
  • subchondral (beneath the cartilage) sclerosis
  • subchondral cysts
  • narrowing of joint space
  • osteophytes

Extrathoracic soft tissue

• breast shadow, nipple
• supra-clavicular, axillary areas → masses
• subcutaneous emphysema

Mediastinum

• size, shape
• mainstem and segmental bronchi, lymph nodes
• great vessles
• hila → relationship, size

Trachea

• position (centered, some rightward shift at level of carina)
  • shift - pneumothorax, mass
  • carina widened - LA enlargement, subcarinal node

Heart Shadow

• cardiothoracic ratio (only on full inspiration PA views)
  • should be < 50%
• enlarged chambers
  • LA - double shadow on right border
  • RA - ↑ width of right hemidiaphragm
  • LV - ↑ heart width
  • RV - lateral view: retrosternal space ↓
• calcifications
• aortic knuckle - unfolded due to age

Chest Wall

• follow pleura for signs of pneumothorax
  • loss of lung markings in the periphery
  • line of visceral pleura seen on expiration view
• pleural thickening
  • ↑ width of white line along inside of ribcage, esp. near diaphragm
• costophrenic angles → pleural effusion
  • small effusions (< 100 mL) may be only seen in the lateral view

Diaphragms

• compare hemidiaphragms
  • obscured → lower lobe pneumonia, pleural effusion
  • flattened → hyperinflation, tension pneumothorax
  • elevated → phrenic nerve paralysis, hepatomegaly
  • air under diaphragms → perforated GI tract

Lung Fields

• compare lung fields in the ICS on L vs. R, up vs. down

Air Space Disease

• cardinal features:
  • air bronchogram
  • fluffy, patchy poorly marginated appearance
  • lobar or segmental distribution
• ddx:
  • pus (pneumonia)
  • fluid (pulmonary edema)
  • blood

Interstitial Disease

• pathology involves the interlobular connective tissue
• cardial features:
  • linear densities - Kerley B lines (< 2 cm long, 1 mm thick, reach lung edge)
  • reticular pattern (thin, well defined linear densities, honeycomb arrangement)
  • nodular pattern
• ddx: pulmonary edema, collagen disease (fibrosis), sarcoidosis, viral pneumonia

Pulmonary Edema

• edema initially collects in the interstitium
  • loss of definition of pulmonary vasculature
  • peribronchial cuffing
    • bronchi seen end-on appear as white rings
• in CHF, the normally thin-walled bronchi become framed in interstitial fluid
  • best seen in vicinity of hila
• Kerley B lines
• reticulonodular pattern
• thickening of interlobar fissures
• with progression, fluid begins to collect in the alveoli, causing diffuse air space disease (bat wing or butterfly pattern), tend to spare the intermost lung fields
• ddx: cardiogenic, renal failure

Atelectasis

• cardinal signs:
  • deviation of a fissure
  • crowding of vessels
  • hilar, mediastinum shift
• common causes: obstructive, compressive
• in absence of a known etiology, bronchogenic carcinoma must be ruled out

Lymphadenopathy

• lymph node groups: paratracheal, hilar, aorto-pulmonary window, subcarinal
• hilar, AP window → widen mediastinum, flatten AP window contour
  • lung cancer, lymphoma, sarcoidosis, and tuberculosis
• subcarinal - ↑ angle of tracheal bifurcation to 90°

Abdomen

• liver size
• spleen size
• stomach (gastric bubble)
• colon (bowel gas)

- free air under diaphragm - pneumoperitoneum

Misc

CHF

• upper lobe redistribution of vessels
• Kerley B-lines (usually seen near diaphragm)
• right effusion at base
• perivascular cuffing
• pulmonary edema (interstitial, then airspace consolidation)
• venous engorgement
  • normally extend 2/3 of the distance to periphery
  • vessels seen to extend farther than normal

Unilateral Left Sided Effusion

• trauma, infection, SLE, PE, malignancy

Mediastinal Mass

• anterior mediastinum
  • thyroid masses, thymomas, teratomas, lymphomas
• middle mediastinum
  • lymphadenopathy, lymphoma, aortic aneurysm
• posterior mediastinum
  • aneurysm of descending aorta, esophageal masses, hiatus hernia
• lateral view
  • RVH
  • effusion → accentuation of lines of major and minor fissures