Basic Interpretation

of Chest

RadiographyBy Dr. Chia Kok King

Five Radiographic Opacities

Air Fat Soft tissue BoneMetal

least opaque to most opaquemost lucent to least lucentBlack to White

Radiographic Opacities & Contrasts

Air Air

Fat Mineral oil

Water Water

Bone Tums

Metal ???

Film Quality

1. PA or AP view.2. Upright/Erect or Supine3. Breath : Inspiration or Expiration4. X-ray penetration : Under- or Over-5. Rotation

PA vs AP views

PA view• Scapula is seen in

periphery of thorax• Clavicles project over

lung fields• Posterior ribs are

distinct• Position of markers

AP view• Scapulae are over

lung fields• Clavicles are above

the apex of lung fields• Position of markers• Anterior ribs are

distinct

Inspiration vs Expiration

Penetration With correct exposure you should barely see

the intervertebral disc through the heart

• If you see them very clearly the film is overpenetrated

• If you do not see them it is underpenetrated

Penetration

Rotation

Pitfalls to Chest X-ray Interpretation

• Poor inspiration• Over or under penetration• Rotation• Forgetting the path of the x-ray beam

Normal Chest X-ray

• Cardiac Structures– Position

• More central in younger infants and children• More on the L side in older infants and teens

– Size• CARDIO-THORACIC RATIO!• Cardiac diameter :

– normal individuals < 15.5 cm in males; <14.5 cm in females.– A change in diameter of greater than 1.5 cm between two

X-rays is significant.

Cardio-thoracic ratio

• seen on postero-anterior (PA) view only

• >50% is considered abnormal in an adult; more than 66% in a neonate.

• Possible causes of a ratio greater than 50% include:– cardiac failure– pericardial effusion– left or right ventricular hypertrophy

*AP views make heart appear larger than it actually is.*

Normal Chest X-ray

• 1. Soft tissue structures– Shadows, most commonly, breast

• 2. Bony structures– Count the ribs– 8 – 10 ribs should be visible on inspiration– Clavicle placement at 2-3 intercostal space (if not,

may be rotated)

Normal Chest X-ray

• 3. Diaphragm– Contour– Rounded with sharp pointed costophrenic and

costocardiac angles– Right diaphragm is usually 1-2 cm higher

Normal Chest X-ray

• 4. Lungs– Start at the top and compare the R and L– Trachea should be midline over the thoracic

vertebrae and air filled– Lung parenchyma becomes lighter as you go down

the lung. If not, it may indicate a lower lobe or pleural effusion

Anatomy

Anatomy

Lobes

• Right upper lobe:

• Right middle lobe:

• Right lower lobe:

• Left lower lobe:

• Left upper lobe with Lingula:

• Lingula:

• Left upper lobe - upper division:

Abnormal Chest X-ray• Radiopacity (whiteness) = increased density• Radiotranslucency (blackness) = decreased density

RadiopacityAlveolar Pattern Interstitial Pattern Vascular pattern

• Fluffy, soft, poorly demarcated opacifications < 1cm in diameter

• Possible causes:1. Pulmonary

edema2. Viral pneumonia3. Pneumocystis4. Alveolar cell

carcinoma

• Consolidation of interstitial tissue

• Looks like branching lines radiating toward the periphery of the lung

• Possible causes:1. Interstitial

pneumonitis2. Pulmonary

fibrosis

• If there is an increase in size of the pulmonary arteries as they extend out into lung – pulmonary hypertension

• If there is a decrease in size, truncation, or obliteration of a pulmonary artery – embolus

• Lack of vascular marking in the periphery – pneumothorax

• Lobar consolidation:– Alveolar space filled with

inflammatory exudate– Interstitium and

architecture remain intact

– The airway is patent– Radiologically:

• A density corresponding to a segment or lobe

• Air bronchogram, and• No significant loss of lung

volume

Consolidation

Consolidation

Atelectasis

• Loss of air• Obstructive atelectasis:

– No ventilation to the lobe beyond obstruction

– Radiologically:• Density corresponding to a

segment or lobe• Significant loss of volume• Compensatory

hyperinflation of normal lungs

• No ventilation to lobe beyond the obstruction

• Trapped air absorbed by pulmonary circulation

• Segmental/lobar density• Compensatory hyper-inflation

of normal lungs.

Atelectasis

Congestive Heart Failure• Increased heart size:

cardiothoracic ratio >0.5 Large hila with

indistinct markings Fluid in interlobar

fissures Pleural effusions,

alveolar edema

Congestive Heart Failure

Alveolar edema (Bat’s wings)

Kerley B lines (Interstitial edema)

Cardiomegaly Dilated prominent

upper lobe vessels Pleural effusion

ARDS

• Congestion• Interstitial and

alveolar edema• Collapsed or

distended alveoli• Bilateral

Pneumothorax

Right side tension

pneumothorax

Left Sided Pneumothorax

Pleural effusion

Right Side

Pleural Effusio

n

RLL Pneumonia

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Fracture of posterior rib #7

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A single, 3cm relatively thin-walled cavity is noted in the left midlung. This finding is most typical of squamous cell carcinoma (SCC). One-third of SCC masses show cavitation

Right Squamou

s Cell Carcinom

a

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Right Middle and Left Upper Lobe Pneumonia

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Cavitation : cystic changes in the area of consolidation due to the bacterial destruction of lung tissue. Notice air fluid level.

Cavitation

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Tuberculosis

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COPD: increase in heart diameter, flattening of the diaphragm, and increase in the size of the retrosternal air space. In addition the upper lobes will become hyperlucent due to destruction of the lung tissue.

Chronic emphysema effect on the lungs

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CHF:a great deal of accentuated interstitial markings, Curly lines, and an enlarged heart. Normally indistinct upper lobe vessels are prominent but are also masked by interstitial edema.

24 hours after diuretic therapy

Chest wall lesion: arising off the chest wall and not the lung

Pleural effusion: Note loss of left hemidiaphragm. Fluid drained via thoracentesis

Lung Mass

The Enlarged Hila

Causes:

1. Adenopathies (neoplasia, infection)

2. Primary Tumor

3. Vascular

4. Sarcoidosis

Small Pneumothorax : LUL

Right Middle Lobe Pneumothorax: complete lobar collapse

Post chest tube insertion and re-expansion

Metastatic Lung Cancer: multiple nodules seen

Tuberculosis

Pleural Effusion

Pulmonary Fibrosis

Cavitating lesion

Miliary shadowing

5. 65 yo male admitted for sepsis. CHF or ARDS?

12. Is the central line correctly positioned?

13. Does ET tube need to be advance or pulled back? Arrow shows location of carina

14. OK for R/T feeding?