Chest Radiology

Front 1

Four basic x-ray densities

Back 1

Air
Fat
Water
Metal (calcium)

Dense objects as white, more easily penetrated as gray/black.

Front 2

Basic x-ray density descriptions

Back 2

Radiopaque
Radiodense
Radiolucent
Opacity - white
Lucency - black

Front 3

Penetration

Back 3

Faint visualization of the intervertebral disc spaces of the thoracic spine

Discrete branching vessels can be identified through the cardiac shadow

Images can be under or over penetrated.

Shown: underpenetration

Front 4

Rotation

Back 4

There should be equal distance between clavicular heads and spinous processes.

If wider on one side, patient is rotated.

Anterior structures move in the same direction as the patient is rotated and posterior structures move in the opposite direction.

Front 5

Inspiration

Back 5

An appropriate deep inspiration in a normal individual is present when the apex of the right hemidiaphragm is visible below the 10th posterior rib.
- Count 8-10 ribs

Poor inspiration can mimic infiltrates on lungs and be confused for pneumonia.

Front 6

Motion

Back 6

The cardiac margin, diaphragms and pulmonary vessels should be sharply marginated in a completely still patient who has suspended respiration.

Front 7

Where are the most commonly missed pathologies located?

Back 7

Right upper lobe

Other areas include retrocardiac, peripheral lung margins and posterior costophrenic sulci.

Rib fractures - pleuritic pain
PE - increased D dimer

Front 8

What is the best approach to take when reading an image?

Back 8

A systematic approach

Look at various structures in a deliberate order, concentrating on the anatomy of each while excluding the superimposed shadows of other structures

Front 9

Lobes of the lungs

Back 9

Right lung - 3 lobes
- RUL - 3 segments
- RML - 2 segments
- RLL - 5 segments

Left lung - 2 lobes
- LUL - 4 segments
- LLL - 4 segments

Lingula of left lung is analogous to RML.

Front 10

Lung fissures

Back 10

Fissures - best visualized on lateral
- Major separates upper from lower lobes
- Minor separates RUL from RML
- Azygos (0.5%), accessory

Front 11

Azygos fissure

Back 11

Normal variant

Can resemble right apical mass

Front 12

Pseudotumors

Back 12

Fluid in fissures that can be mistaken for tumors.

Front 13

Frontal cardiac view

Back 13

Right cardiac border - right atrium

Left cardiac border - left ventricle

The SVC forms a right paramedian border

Front 14

Lateral cardiac view

Back 14

Anterior cardiac border - right ventricle

Posterior cardiac border - LV and LA

The IVC is seen best on lateral projection. The posterior border is evident in contrast to the air-filled lungs.

Left ventricular hypertrophy can be seen as enlargement on lateral view.

Front 15

Hila

Back 15

Pulmonary arteries, veins & airways
- Airways do not produce significant shadows therefore the majority of detectable structures are vascular.

Left Pulmonary Artery
- Courses over left upper lobe bronchus
- Directed posterolaterally
- On lateral, behind tracheal air column

Right Pulmonary Artery
- Courses beneath right upper lobe bronchus
- Directed horizontally
- On lateral, anterior to tracheal air column

Front 16

Hilar relationship

Back 16

70% left hilum higher than right

30% hila equal

Right NEVER higher than left

Front 17

Pulmonary veins

Back 17

More horizontal

Best seen on lateral

Don’t confuse with retrocardiac space or infiltrate

Front 18

Aortopulmonary window

Back 18

A “space” located below the aortic arch and above the left pulmonary artery, bordered by aortic valve.

Normally contains fat

An opacified window is a “red flag”

If window not present, could indicate an aortic dissection or MI.

Front 19

Hilar lymphadenopathy

Back 19

If right is higher than left, it can indicate a mediastinal lymphadenopathy.

Front 20

Mediastinum anterior

Back 20

4 Ts
- terrible lymph nodes
- thymus (thyoma)
- thyroid (substernal goiter)
- teratoma (shown)

Front 21

Mediastinum middle

Back 21

Heart, vessels, lung root
- lymph nodes
- congenital cysts
- diaphragmatic hernias
- vascular lesions

Front 22

Thymus

Back 22

Sail sign may be present in pediatric patients.

Front 23

Medistinum posterior

Back 23

Esophagus, aorta
- neurogenic tumors
- esophageal lesions
- vertebral lesions
- congenital cysts

Front 24

Diaphragm

Back 24

Sharply marginated domes with the apex approximately mid-clavicular

Peripheral margins define the costophrenic sulci

Right diaphragm higher than left due to position of the liver

Always look below the diaphragm

Front 25

Costophrenic sulci

Back 25

Sharp, costophrenic angles
- Rounded angles could indicate pleural effusion.

Front 26

Laterally dispaced diaphragm

Back 26

Apex of diaphragm laterally displaced due to subpulmonic effusion.

Front 27

Air under diaphragm

Back 27

Air under the diaphragm is an ominous sign that should not be overlooked.

Any gas should have an outline of visceral structure.

Chilidi's sign - colonic interposition

Front 28

Diaphragmatic rupture

Back 28

Traumatic diaphragmatic rupture (mimics a pleural effusion).

Front 29

Trachea

Back 29

Look for deviations, may indicate pneumothorax.

Front 30

Osseous structures

Back 30

Bony structures

Front 31

Metastatic disease

Back 31

Ivory vertebral body

Front 32

How to distinguish skin folds from abnormalities

Back 32

Pneumothorax or skin fold?
- Second view – inspiratory/expiratory views
- Hyperlucent lung – mastectomy may appear this way

Front 33

Silhouette sign

Back 33

When two structures (opacities) of similar density abut one another, anatomical margins are lost.

Front 34

Air bronchogram

Back 34

Indicates air space disease with fluid density outlining the air-filled bronchi.

Shown: right middle lobe pneumonia

Front 35

Extrapleural sign

Back 35

A mass outside the pleural space has characteristic, smoothly sloped margins.

Front 36

What should you examine when looking at lungs on an image?

Back 36

Are they expanded to the periphery?

Symmetry

Status

Patterns of parenchymal opacity
- air space (alveolar)
- interstitial
- atelectasis
- nodule/mass

Front 37

Air space disease

Back 37

Produced when air in terminal air spaces is replaced with “stuff”

Radiographic characteristics
- lobar or segmental distribution
- fluffy margins
- tendency to coalesce
- air bronchograms
- rapidly changing over time
- “bat wing” distribution

Acute
- blood
- pus
- fluid

Chronic
- lymphoma
- TB
- proteinosis

Front 38

Interstitial disease

Back 38

Produced by processes that thicken the interstitial compartments
- water, blood, tumor, cells, infection, fibrosis

Radiographic patterns
- linear
- reticular
- reticulonodular
- nodular
- “ground glass”
- curly B lines

Acute - interstitial edema, viral/atypical

Chronic - multitude (CHF)

Front 39

Atelectasis

Back 39

Obstructive
- oxygen reabsorbed
- mucus plug / F.B. / tumor

Passive
- mass effect / pleural
- pleural effusion

Compressive
- mass effect / lung
- bulla, tumor, abscess

Cicatricial
- scarring & retraction
- TB, fibrosis

Adhesive
- surfactant deficiency
- R.D.S. of Newborn

Front 40

Signs of volume loss

Back 40

- movement of lobar fissures
- crowding of the lung markings
- ribs more closely spaced
- elevation of the hemidiaphragm
- mediastinal shift
- tracheal shift
- consolidation

Front 41

Projectional phenomenom

Back 41

Anterior objects appear larger

Can mimic congestive heart failure

When you lie down, vessels compressed

Front 42

Pleural effusion

Back 42

Fluid layering on film

Front 43

Sulpulmonic effusion/mass

Back 43

Diaphragm raised on one side
- Rule out phrenic nerve paralysis
- Can be normal variant

Front 44

Consolidation

Back 44

Very dense, masslike
Acute
- Pneumonia
- Blood
- Atelactesis

Chronic
- Lymphoma
- BAC (bronchioloalveolar carcinoma cell)

Order follow up x-ray to see if consolidation has cleared

Front 45

Pulmonary edema

Back 45

Hilum thickening
Interstitial thickening
- Perpendicular lines can be seen – curly B lines
- Also seen in CHF
Fluid spills over and can be seen on periphery
Can then develop a pleural effusion
Cardiogenic – enlarged heart – CHF

Front 46

How do you distinguish between an atelectasis and pneumothorax?

Back 46

Volume loss results from atelectasis
Subsegmental atelectasis
- non-pathological

How do you discern between atelectasis and another problem?
- Volume loss
- Trachea, mediastinum displace towards opacity

Front 47

Medistinal widening

Back 47

With pain – CT to rule out aortic dissection
Use contrast to light up vessels
- Pulmonary embolism
- Any traumatic setting
- Unless contraindicated

Front 48

Deep sulcus sign

Back 48

Secondary sign of pneumothorax