Radiology: Chest X-Rays

SoB
Chest pain
Cough
Hemoptysis
Fever
Unexplained weight loss
(Signs may be hypoexemia or abnormal pulmonary exam)
What symptoms can be indication for CXR?
Evaluating placement of tubes (e.g. NG, central line, endotrachial)
Screening for pneumothorax after lung biopsy/central line placement/pacemaker placement
Evaluation of suspected pacemaker lead fracture
What indications exist, other than signs or symptoms, for taking a CXR?
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Chest against detector
Away from source
Hands on hips (if erect)
What position should a patient be in for a CXR?
Radiolucent – not dense; allows X rays through
Radioopaque – dense(r); absorb X rays
Distinguish between the terms radiolucent and radioopaque
Air
Soft tissue/fluid
Bone
Metal
What are the four main tissues distinguishable on X ray, in order from most radiolucent to most radioopaque?
Bowel obstruction
Pyloric stenosis in children
What main two pathologies will give you a massive gastric bubble?
Thickness
Density
Duration of exposure (longer exposure, the darker the image)
What are the three main factors affecting how much X ray is absorbed by a feature on an X ray?
PA (most common – best)
Lateral (often done with a PA view, to assist with picture)
AP (usually portable for immobile pts)
What are the three main views used in a CXR?
AABCDEF system

(Assess quality)
Airways
Bones/soft tissue
Cardiac + mediastinum
Diaphragm
Effusions/pleura
Fields (lung fields)
Other (lines, tubes, devices, surgeries)

DRSABCDEF is also good:

Details
RIPE
Soft tissues and Bones
Airway
Breathing (and lung fields)
Circulation
Diaphragm + Pleura
Extras
Field

I use DR ABCDEF

What is a good system for trainees to interpret CXR?
What three structures are you looking at when you assess the airways?
Trachea
Right bronchus
Left bronchus
What three structures are you looking at when you assess the airways?
What 5 bones do you need to examine when assessing the bones in a CXR?
Clavicles
Scapula (only if PA or AP is unknown)
Ribs
Vertebrae
Sternum (lateral CXR)
What 5 bones do you need to examine when assessing the bones in a CXR?
What 8 features of the heart and great vessels do you need to assess when looking at a CXR?
Ascending Aorta
Aortic Arch
Aortopulmonary window (little notch between arch and left pulmonary artery – contains recurrent laryngeal nerve and lymph nodes)
Left pulmonary artery
Right pulmonary artery
Left atrium
Right atrium
Left ventricle

(Descending aorta can also often be seen)

What 8 features of the heart and great vessels do you need to assess when looking at a CXR?
Left edge of the vertebral bodies
What does the descending aorta correspond with?
Which aspect of the hemidiaphragms are represented as the 'bottom' on a PA view X ray?
Top
Which aspect of the hemidiaphragms are represented as the ‘bottom’ on a PA view X ray?
Asbestosis
Pneumothorax
Pleural thickening
When is the pleura likely to be seen?
What is the only lung fissure sometimes visible on CXR?
Horozontal fissure of right lung
(Oblique fissures usually not seen)
What is the only lung fissure sometimes visible on CXR?
How do you assess which lobe consolidation is located in?
You must use both the PA and lateral views:

(dotted lines divide right upper, middle and lower lobes)

How do you assess which lobe consolidation is located in?
Costophrenic angle blunting would indicate fluid in which lobe?
Lower lobe

(image is middle lobe, to show it goes all the way to diaphragm)

Costophrenic angle blunting would indicate fluid in which lobe?
Rotation
Inspiration
Penetration/exposure
What are the three factors affecting technical quality of a CXR?
What are the consequences of poor rotation around the z axis (front axis)?
Possibly unseen costophrenic angle
Gastric bubble and intraperitoneal air may not be visible
What are the consequences of poor rotation around the z axis (front axis)?
By the amount of lung space above the clavicle
How do you identify if a patient is rotated around the x (horozontal) axis?
Dilatation, and possibly pathology further on from the object
How might you identify a radiolucent foreign body in the airway?
Improved view of what is behind the clavicles
What is the one advantage of the lordotic view (rotation around x axis)?
How do you identify rotation around the y (vertical) axis?
Distance between the spinous processes and each clavicle should be equal.
If one is shorter, that side is typically rotated forward
How do you identify rotation around the y (vertical) axis?
Lung volumes appear low

Lung markings appear falsely prominent (appears like pulmonary edema)

Cardiac silhouette/mediastinum appear enlarged

What are the main 3 consequences of inadequate inspiration on CXR?
Poor inspiratory effort
Restrictive lung disease
What may appear as low lung volume on CXR?
Duration of exposure (mili-amp seconds)
Energy of photons (kilovolt peak)
Source to image distance (SID)
What are the three parameters altered by radiology technicians to adjust penetration/exposure/
Outline of the vertebral bodies is just visible behind the heart silhouette
How do you know if penetration is adequate and there isn’t too much/too little exposure?
*Pneumothorax* is probably most common, but also surgery, trauma, gas gangrene, etc etc
What is probably the most common cause of subcutaneous emphysema?
Look for rotation – look at space above clavicles, costophrenic angles, and distance from spinous processes to clavicles

Identify possible poor inspiratory effort – count number of posterior ribs visible; should be 9-10

Assess exposure and penetration – identify the thoracic vertebrae behind the hear

What is the procedure for assessing technical quality of a CXR?
Narrowing
Deviation
Foreign body
What are the three things to look for in airways on CXR?
Subglottic airway narrowing is a common finding in which diseases?
*Croup* (seen – steeple sign), tracheitis
*Tracheal stenosis* or Tracheomalacia

(also, *shadows* from overlying mediastinal structures – common cause of misdiagnosis)

Subglottic airway narrowing is a common finding in which diseases?
Trachial deviation away from pneumo – usually only if massive, like in tension pneumo
What airway sign do you expect to see in Pneumothorax?
Pneumothorax
Pleural effusion
Large mass

(all of these increase the mass/fluid in the lung, pushing everything away)

Which abnormalities deviate the trachea away from the affected side?
*Atelectasis* (collapsed lung – e.g. from bronchus obstruction)
*Lobectomy*/pneumonectomy
*Pleural or Pulmonary fibrosis* (rare, especially unilaterally)

(these tend to shrink one lung, pulling everything towards it)

Which abnormalities deviate the trachea towards the affected side?
What might a bullous lesion in a smoker appear like?
Being pointed at by the arrow

(This lung also includes mild hyperinflation and vertical stretching of the heart border. All consistent with a long pack year history)

What might a bullous lesion in a smoker appear like?
Lung zones – lower, middle and upper
If there is a pathology, such as consolidation, that you cannot attribute to a particular lobe, how should describe its location?
90 degrees
What is the normal cut-off of the carinal angle?
Fracture (old or new)
Deformed (e.g. kyphosis, scoliosis)
Sclerosed (solitary vs multiple vs diffuse)
Lytic (solitary vs multiple)
Osteopenic
Notched
What are the 6 abnormalities that can be seen on bones in CXRs?
How is an old fracture identified on a CXR?
*Focal thickening* of the rib consistent with callous formation. Careful to not mistake for sclerotic bone lesion

(hint – RHS, 8th)

How is an old fracture identified on a CXR?
Clavicular
Vertebral (usually compression fractures)
Sternal (lateral view)
Other than rib fractures, what fractures can be identified on CXR?
Increased density; can be focal or diffuse
How does bone sclerosis appear on X ray?
Osteoblastic metastases
Primary bone tumors
Benign bone lesions
Paget’s disease
Chronic osteomyelitis
What are the main causes of sclerotic bone lesions?
How do impanted intravenous ports appear on CXR?
This.

Note breast implant on left breast, and arrows pointing at sclerotic lesions

How do impanted intravenous ports appear on CXR?
Reduced density of bones – can be solitary or multiple
How do lytic bone lesions appear on CXR?
Osteolytic metastases
Multiple myeloma
Various benign cyst-like bone lesions
Paget’s disease
Acute osteomyelitis
What are the main causes of lytic bone lesions?
Focal deformation of one or more ribs; etiology usually depends on whether superior or inferior side is affected
What is rib notching?
Osteogenesis imperfecta
Hyperparathyroidism
Connective tissue disease
Local pressure
Which diseases might lead to rib notching on the superior surface?
Subcutaneous emphysema
Breasts
Hematomas or swelling
What are the things you should be looking for in soft tissues on CXR?
What diseases might lead to rib notching on the inferior surface?
*Coarctation of aorta*

*Subclavian or SVC* obstruction

s/p *Blalock Taussig shunt* (only upper 2 – post procedure for congenital heart disease)

What diseases might lead to rib notching on the inferior surface?
What is the prevalence of a cervical rib?
0.5-1%

Anatomic variant; only concern is possible risk of thoracic outlet syndrome by compression of vascular structures/brachial plexus

What is the prevalence of a cervical rib?
What are the main causes of subcutaneous emphysema?
Internal:
Dissecting pneumothorax
Pneumomediastinum
Pulmonary interstitial emphysema

External:
Penetrating chest wall trauma
Chest tube complication

Local:
Necrotising infection by gas producing organism (gas gangrene)

What are the main causes of subcutaneous emphysema?
Lateral and PA film
Assess for bone injuries, pneumothorax
How do you assess shrapnel injuries?
Asymmetry with other lungs; always check both sides and correlate to history
What on CXR can help identify both pathologies, foreign bodies, and objects outside the body?
Why does an AP film make the heart look bigger?
Because the X ray shadow it casts onto the film is enlarged
Why does an AP film make the heart look bigger?
Define cardiomegaly
Cardiothoracic ratio >50% on PA film (normally 40%)

Most common cardiac pathology on CXR

Define cardiomegaly
Left or right sided heart failure.
What is the main cause of cardiomegaly?
Pericardial effusion – they are almost indistinguishable
What can cardiomegaly commonly be confused with?
Left atrial enlargement will create what signs on CXR?
*Splaying of carinal angle* to >90 degrees
*Double density sign* (where two lines of density can be seen at the right heart border (one is L atrium; one is R)

(both seen in image)
(mitral valve damage is evidenced in the CXR)

Left atrial enlargement will create what signs on CXR?
Left sided heart failure

Mitral valve disease (e.g. mitral stenosis, regurg, prolapse all do it)

What are the main two causes of left atrial enlargement?
What is the main sign of right ventricular enlargement?
*Filling of retrosternal space*

(R atrium is most anterior)

What is the main sign of right ventricular enlargement?
Pulmonary hypertension (e.g. COPD)

Pulmonary valve disease

What are the main causes of right ventricular enlargement?
What are the main findings of pericardial effusion on CXR?
Enlarged heart silhouette
“*Water-bottle Sign*” (seen)
*Oreo-cookie sign* (looks like a hidden oreo cookie on lateral CXR, just above diaphragm)
What are the main findings of pericardial effusion on CXR?
Trauma
Viral pericarditis
MI complication (Dressler’s, free wall rupture)
Iatrogenic (RV biopsy, EP procedures)
What are the main acute causes of pericardial effusion?
Malignancy
Renal failure
Collagen vascular disease
Hypothyroidism
TB
What are the main causes of sub-acute or chronic pericardial effusion?
1/12,000. Not common
What is the incidence of dextrocardia?
>8cm
What measurement defines a widened mediastinum?
Suboptimal technical quality
(rotation, poor inspiratory effort, AP view)
What is the main cause of widened mediastinum on CXR?
What are the four mediastinal regions?
Defined by lateral CXR:

Anterior – anterior to pericardium + inferior to sternal angle
Superior – superior to sternal angle
Middle – everything within percardium + lymph nodes and esophagus
Posterior –

What are the four mediastinal regions?
Lymphoma
Enlarged thyroid
Thymus
Teratoma
Aortic aneurysm
What are the common masses that occur in the anterior and superior mediastinum?
Lymphadenopathy (from any cause)
Aortic aneurysm
Pericardial cysts
Dilated esophagus
Hiatial hernia
What are the common masses occuring within the middle mediastinum?
Neurogenic tumors
Extension of spinal masses (bone tumors, infections, etc)
What are the common masses occuring within the posterior mediastinum?
Chest CT
What would be your next course of action if you identify a mediastinal mass?
How does an aortic aneurysm appear on CXR?
Long looking mass – really enlarged aorta. Often calcified (middle)
How does an aortic aneurysm appear on CXR?
*Malignancy* (either primary lung cancer, lymphoma or metastasis)
*Infection* (esp TB and viruses)
*Infiltrative disease* – sarcoid, silicoidosis
*Local mass* – pulmonary HT, cyst, aneurysm
What are the four categories of hilar enlargement differential diagnosis?
How might severe pulmonary hypertension appear on CXR?
Note the hilar enlargement, and cardiomegaly
How might severe pulmonary hypertension appear on CXR?
What features on CXR might you look for in suspected lung cancer?
Primary tumor
Hilar enlargement
What features on CXR might you look for in suspected lung cancer?
What is the hilum overlay sign?
Used to distinguish hilar mass from one over or under it

When mass arises from hilum, the adjacent pulmonary vessels become obscured. If you can still make out the vessels, it’s not hilar

(e.g. this saccular aortic aneurysm)

What is the hilum overlay sign?
What are you looking for on a pneumothorax?
Areas of *no lung markings*

*Discrete line* that is the lung lining

*Difference in CXRs during little and full inspiration* (more marked on poor inspiration due to higher proportion of air within pneumo)

What are you looking for on a pneumothorax?
Thickness of rim of air around the lung at the level of the hilum

<2cm is small >2cm is large

Technically defined by risk of intervention (needle trauma) vs risk of not intervening (growth, symptoms, etc)

How is pneumothorax measured?
What tricks are there to help make pneumothorax identification easier?
Compare inspiratory vs no inspiratory CXRs
Look at inverse image
AP film (for *deep sulcus sign*; seen)
What tricks are there to help make pneumothorax identification easier?
Primary – develops independent of lung disease or pathology

Secondary – develops secondary to iatrogenic procedure, COPD, trauma, CF, pneumonia.

Distinguish between a primary and secondary pneumothorax
What are the main characteristics of a pleural effusion you must identify on CXR?
Uni vs bilateral
Size
Free-flowing vs loculated
Associated findings (suggest etiology)
What are the main characteristics of a pleural effusion you must identify on CXR?
What might be necessary to do to find a small pleural effusion on CXR?
Lateral X ray – they are visible here 1st.

Requires several hundred mls of fluid before seen on PA

What might be necessary to do to find a small pleural effusion on CXR?
How do you distinguish between a free-flowing and loculated effusion?
Free-flowing – adheres to gravity; makes nice meniscus
Loculated – Unusual location; seems to defy gravity. May warrant CT to distinguish from a mass
How do you distinguish between a free-flowing and loculated effusion?
What other view may be needed to assess how free flowing an effusion is?
Lateral decubitus view (pt lying on their side)
What other view may be needed to assess how free flowing an effusion is?
What is a subpulmonic effusion?
Fluid between lung and diaphragm – basically forces the lung upwards, like a giant liver
What is a subpulmonic effusion?
What is a pseudotumor, and what will make you suspicious of it?
*Fluid in a lung fissure* (most commonly horozontal)

Think of it if “mass” is at fissure and has well defined margins

What is a pseudotumor, and what will make you suspicious of it?
Transudative – due to *hydrostatic and oncotic pressure* imbalance

Exudative – due to *pleural inflammation or lymphatic obstruction*

Any of Light’s Criteria = Exudative:
-LDH >2/3rds upper limit
-pProtein:sProtein >0.5
-pLDH:sLDH >0.6

Distinguish between a transudative effusion and exudative effusion?
Heart failure
Hepatic hydrothorax (ascites leakage)
Hypoalbuminaemia
Nephrotic syndrome
What are the main causes of transudative effusion?
Pneumonia/other infection (empyema)
Malignancy
PE
TB
Pancreatitis
Sarcoidosis/Rheumatological diseases
What are the main causes of exudative effusions?
What may happen if assessing a pleural effusion in a very sick hospitalized patient?
Blurred effusion:
What may happen if assessing a pleural effusion in a very sick hospitalized patient?
What might a pleural plaque look like on CXR?
Typically *bilateral*

*Multifocal*

Relatively *symmetric*

What might a pleural plaque look like on CXR?
Prior asbestos exposure.

You can put the CXR down now; you’ve made your Dx, all finished

What do pleural plaques almost always indicate?
How might pleural thickening appear?
As the name might suggest
How might pleural thickening appear?
What are the main causes of pleural thickening?
Prior infection
Prior hemothorax
Occupational exposure (silicosis, asbestos)
Radiation
Malignancy (normally metastasis; primary mesothelioma seen)
What are the main causes of pleural thickening?
What are the main causes of an elevated diaphragm?
Diminished lung volume (atelectasis)
Phrenic nerve paralysis
Eventration of diaphragm
Subphrenic abscess
Hepato/splenomegaly
What are the main causes of an elevated diaphragm?
What are the main four causes of pneumoperitoneum?
Perforated viscus (PUD, appendicitis, diverticulitis, malignancy, SBO/LBO, endoscopy complication)
Post-operative
Trauma
Peritoneal dialysis
What are the main four causes of pneumoperitoneum?
How does a hiatal hernia appear on X-ray?
Pocket of air in mediastinum
How does a hiatal hernia appear on X-ray?
How might pneumomediastinum appear on CXR?
Thin line at mediastinum

Often co-exists with subcutaneous emphysema
Can be mistaken for pneumopericardium – this has a more demarcated, single band though

How might pneumomediastinum appear on CXR?
Trauma
Esophageal rupture
Asthma
Post-neck or chest surgery
Barotrauma (e.g. diving)
What are the main causes of pneumomediastinum?
What is Chilaiditi's sign?
Gas seen between liver and diaphragm:

often due to small liver or bowel movement/gas. Distinguished from free air by haustral line

What is Chilaiditi’s sign?
Suboptimal inspiratory effort
Suboptimally timed exposure
Restrictive lung disease
Subpulmonic effusion
What are the main causes of reduced lung volume?
What features will make you suspect hyperinflation on CXR?
>10 posterior ribs seen

Flattening of diaphragms

Diffusely increased lucency of lungs

Thin Heart

What features will make you suspect hyperinflation on CXR?
COPD
Acute asthma exacerbation
What are the (almost exclusively) two causes of hyperinflation?
Describe alveolar opacities
Hazy with poorly defined margins. Can sometimes respect lobar boundaries.

Caused by edema, pus or blood within alveoli and terminal branches

Describe alveolar opacities
*Cardiogenic pulmonary edema* (elevated pulmonary wedge pressure):
Long-standing CMP exacerbation
Acute MI
Arrhythmia
Myocarditis
Endocarditis (causing mitral or aortic regurgitation)
Any other cause of CHF

*Non-cardiogenic pulmonary edema* (normal pulmonary wedge pressure):
Spectrum between acute lung injury and ARDS (based on severity of hypoxemia)

What are included in the two main subtypes of DDx for alveolar opacity?
Sepsis
Pancreatitis
Severe pneumonia
Severe burns
Near drowning
Post-transfusion
CNS catastrophe
What are the main causes of ARDS?
Air bronchograms
Peribronchial cuffing
Kerley lines
Cephalization
Bat’s wing pattern
What are the five radiographic features used to distinguish cardiogenic from non-cardiogenic edema on CXR?
What is an air bronchogram, and what does it indicate?
Visible bronchi due to opacification of adjacent alveoli. Also a feature of Peribronchial cuffing

(note visible bronchus just lateral to right heart border)

What is an air bronchogram, and what does it indicate?
What is peribronchial cuffing?
Cross-section of bronchi visible on CXR

(note two small circles in upper left quadrant)

What is peribronchial cuffing?
What are Kerley A lines?
Diagonal unbranching lines extending 2-6cm from the hilum. Represent channels of lymphatics
What are Kerley A lines?
What are Kerley B lines?
Faint, thin, horozontal lines coming in around 2cm from lung periphery, usually near bases. Represent interlobular septa.

Can be seen in pulm edema, as well as non-cardiogenic edema

What are Kerley B lines?
What is cephalization?
Increased visibility of pulmonary vessels at apices as compared to the bases – suggests left atrial pressure

Quite subjective and not good diagnostically due to interobserver variability

What is cephalization?
What is the Batswing pattern, and where is it seen?
*Bilateral, perihilar opacification*

Seen in cardiogenic pulmonary edema, pneumonia, inhalational injury, pulmonary alveolar proteinosis and pulmonary haemorrhage

What is the Batswing pattern, and where is it seen?
Cardiogenic often has cardiomegaly
Homogenous distribution of opacity in cardiogenic; more patchy in non-cardiogenic
Air bronchograms are common in non-cardiogenic edema, whereas peribronchial cuffing is common in cardiogenic edema
Concurrent pleural effusions and Kerly B lines are more common in cardiogenic edema (as is batwing and cephalization, but less specific)
Using the 5 distinguishing features, how do you tell apart cardiogenic from non-cardiogenic edema?
Multilobar pneumonia
Diffuse alveolar haemorrhage
What are the two causes of alveolar opacity without edema?
What are the three subtypes of interstitial opacities?
Reticular (lines; can look lace- or net-like)
Nodular opacities
Reticulonodular opacities
What are the three subtypes of interstitial opacities?
Idiopathic pulmonary fibrosis
Connective tissue disease
Interstitial or atypical pneumonia
Drug toxicity
Chronic aspiration
The differential diagnosis for diseases creating a predominantly reticular pattern is very large. The main common ones are as follows:
Nodules >2cm
Nodules <2cm
What are the two “subtypes” of nodular interstitial opacity? (considerable overlap between them)
Miliary TB
Fungal infection
Worker’s exposure pneumonia (silicosis, coal worker’s)
Sarcoidosis
What are your main DDxs for nodules under 2cm in interstitial opacity?
Metastatic cancer*
Lymphoma*
Hypersensitivity pneumonitis (only subacute)
Sarcoidosis*
Granulomatosis w/ polyagniitis
Rheumatoid nodules
What are your main DDxs for nodules >2cm
Alveolar:
Lobar or segmental distribution (unless Bat’s wing)
Relatively hazy margin
Air bronchograms (if non-cardiogenic)
Rapidly change over time
“Fluffy, cotton-wool, cloud-like”

Interstitial:
No respect for lobar or segmental boundaries
Relatively sharp margin
Changes slowly over time
Reticular, nodular, or reticulonodular

Outline the main differences between alveolar opacities and interstitial opacities
Apical zone (above clavicles)
Upper zone (clavicle to superior hilum)
Midzone (anything at level of hilum)
Lower zone (Everything below the hilum)
What are the four lung zones?
Opacity – white colour, due to density
Consolidation – large opacity, usually filling an entire lobe or more, of homogenous appearance
Infiltrate – fluid, due to infection, building up. Poor term
Distinguish between the terms opacity, consolidation and infiltrate
Loss of normally visible border of an intrathoracic structure, caused by an adjacent pulmonary density
What is the Silhouette sign?
RUL – Ascending aorta
RML – Right heart border
RLL – Right diaphragm
LUL – Aortic knob + left heart border
LLL – Left diaphragm + descending aorta
There is a particular silhouette sign associated with all lobes of the lungs. Identify which structure has its visible border obliterated by each lobe:
What is the spine sign in CXR?
Indicates opacity in the lower lobe – spine should get darker on lateral CXR as it approaches the diaphragm
What is the spine sign in CXR?
Pneumonia (by far and away most common)
Malignancy
Pulmonary infarction
Pulmonary haemorrhage
Vasculitis
What are the main causes of focal opacity on CXR?
Segmantal/lobar pneumonia affects the alveoli
Bronchopneumonia affects the walls of airways
What is the difference between segmental and bronchopneumonia?
How are broncho and lobar pneumonia distinguished on CXR?
Lobar – Homogenous consolidation, air bronchograms, borders corresponding to fissures (seen; also with spine sign. LLL)

Broncho – Patchy opacification, vague borders, often bilateral

How are broncho and lobar pneumonia distinguished on CXR?
Which type of pneumonia has a sperical shape and is more common in children than adults?
Round pneumonia; often mistaken for tumor/mass. Distinguish based on Hx, and on resolution over days to weeks
Which type of pneumonia has a sperical shape and is more common in children than adults?
What on CXR will indicate bronchopneumonia?
Opacification bilateral
Not sharply defined
No air bronchograms

(Think Staph aureus or Pseudomonas)

What on CXR will indicate bronchopneumonia?
Well circumscribed
Round density
<3cm Compare to previous CXRs
How do lung nodules typically appear on CXR, and what must you do after you identify one?
*Cancer* – primary, metastatic, lymphoma, carcinoid

*Infectious/inflammatory* – granuloma, pneumonia

*Congenital* – arterial venous malformation, bronchogenic cyst

What three categories exist for causes of single lung nodules?
What technique can help you identify a pulmonary nodule?
Increase the contrast (questionable; didn’t help me…)
What technique can help you identify a pulmonary nodule?
What will change in your differential diagnosis if there are multiple nodules on CXR?
Still worried about cancer – but more metastases and lymphoma, rather than primary

Infectious or inflammatory causes more concerning:
Fungal*
Mycobacteria*
Septic emboli
Parasites (e.g. schistosomiasis)
RA*
Vasculitis
Amyloidosis*

What will change in your differential diagnosis if there are multiple nodules on CXR?
How does pulmonary embolism affect CXR?
Usually no changes

Hampton’s hump (wedge-shaped opacification due to necrosis)
Westermark Sign (focal reduction in appearance of lung markings; seen)
Fleishner sign (prominent central pulmonary artery – distension due to large PE)

How does pulmonary embolism affect CXR?
Pneumonia (Staph, pseudomonas, klebsiella)
Abscess
TB
Malignancy (SCC most common)

Septic emboli (IVDUs)
5% pulmonary infarcts do this eventually
Granulomatosis w/ polyangiitis
RA
Pneumatocoele, aspergilloma (fungus ball)

What are the common causes of lung cavitation?
By mechanism or radiographic appearance:

*Obstructive*
*Non-obstructive* – Passive, compressive, adhesive, cicatrical

Atelectasis, loss of lung volume due to collapse of lung tissue, is classified how?
Airway obstruction followed by gas resorption within non-ventilated alveoli

Tumors, mucus plugs, foreign bodies and external compression are the more common causes

Describe the mechanism and common causes of obstructive atelectasis
Passive – pleural effusion or pneumothorax; different layers of pleura become separated, and elasticity pulls visceral layer in

Compressive – tumor, elevated diaphragm, any other mass

Adhesive – lack of surfactant; ADRS, IRDS, radiation pneumonitis

Cicatrical – severe parenchymal scarring (TB, idiopathic pulmonary fibrosis)

What are the main causes of non-obstructive atelectasis?
What is linear/plate-like atelectasis?
Thin, wide plate of atelectasis parallel to diaphragm or perpendicular to pleura. Seen mostly in acute PE, or poor diaphragmatic motion
What is linear/plate-like atelectasis?
What is round atelectasis?
Infolding of redundant pleura; usually in asbestos exposure

(Hint; not the empty bit on the LL. Dense bit on the right lung, with the characteristic tail. Differentiated from a mass by this tail, and previous asbestos exposure)

What is round atelectasis?
Entire lung segment collapses. Needs CT to be seen
What is segmental atelectasis?
Extreme atelectasis, usually due to obstruction (tumor, mucus, foreign body, external compression)
What is lobar atelectasis?
What are the main radiographic findings seen in lobar atelectasis?
Elevation of ipsilateral hemidiaphragm
Mediastinal shift
Juxtaphrenic peak sign (particularly upper lobe; seen)
What are the main radiographic findings seen in lobar atelectasis?
How does the right upper lobe typically collapse in atelectasis?
Superiorly and medially

Creates RU medial density and superior displacement of hilum and horozontal fissure

How does the right upper lobe typically collapse in atelectasis?
Which lobe is the most common to collapse, and what are the radiographic signs?
Right Middle Lobe:

Hard to see on PA/AP. Only has slight reduction in volume.
Easier to see on lateral, with a shadow over the heart

Which lobe is the most common to collapse, and what are the radiographic signs?
How does right lower lobe collapse appear?
Wedge-shape behind right atrium. Oblique fissure more often seen
How does right lower lobe collapse appear?
How will you identify LUL collapse?
Usually anterior collapse (see lateral CXR)
50% also have medial collapse
Other 50% usually have part of LLL shift up between LUL and aortic arch (seen)
How will you identify LUL collapse?
What are the common findings in LLL collapse?
Triangular opacity behind the heart
Inferior displacement of left hilum
Obscuring of outline of descending aorta
What are the common findings in LLL collapse?
What is a central line, and how does it appear on CXR?
Intravenous line into central vein, most commonly internal jugular, subclavian or femoral vein.
Can be put in at the vein, or peripherally (PICC line)

The tip will reach the junction of the SVC and right atrium (no further – can induce arrhythmia)

What is a central line, and how does it appear on CXR?
How does a PA catheter appear on CXR?
Through SVC, 270 degrees around heart silhouette and finishing about 1cm beyond cardiac silhouette
How does a PA catheter appear on CXR?
How does an endotrachial tube appear on CXR?
Note the total left atelectasis due to ET tube going into right bronchus – no air makes it into left lung, so collapse over minutes to hours

Note – tracheostomy tubes appear shorter

How does an endotrachial tube appear on CXR?
How does a nasogastric tube appear on CXR?
Can be hard to see the tube in esophagus (visible ever so slightly on image), so check stomach

Confirm it doesn’t go into the lung – always do CXR after NG tube placement

How does a nasogastric tube appear on CXR?
Chest tube
Used for treatment of large empyema, effusion or pneumothorax
Chest tube
IV Port
Used mostly for chemotherapy due to lower rates of infection

Take blood from it, as well as their peripheral blood, if pt has febrile neutropenia

IV Port
Dual chamber pacemaker
Dual chamber seen.

Single chamber and biventricular are other variants
Also ICD (implantable cardiac defibrilator)

Dual chamber pacemaker
How might an Atrial Septal Defect Closure device appear?
Metal flower, sliced open lemon, in centre of heart
How might an Atrial Septal Defect Closure device appear?
USB stick – used to detect arrhythmias
What does an impantable loop recorder look like?
Pneumothorax
Cardiac perforation (tamponade)
Lead fracture (device breaks; maybe suspect in pacemaker which shuts down early)
Twiddler’s syndrome (patient plays with implanted device, causing it to rotate in chest and coil its leads)
What are common complications from implantations of cardiac devices?
How does sternotomy appear on CXR?
Deformed paperclips on the sternum, holding it together. Sign of open heart surgery

(Surgical clips from coronary bipass graft also seen here)

How does sternotomy appear on CXR?
What types of prosthetic heart valves can be seen on CXR?
What types of prosthetic heart valves can be seen on CXR?
How do you tell which valve has been replaced on the CXR?
En face vs in profile. Not 100%, but reasonable method
How do you tell which valve has been replaced on the CXR?
Also, with identifying valves:
Also, with identifying valves:
Abscess
Hemothorax + Pneumothorax (Haemopneumothorax)
What are the two times you will see air fluid levels in CXR?
Pneumothorax
What is the most common cause of visible pleura?
Swallowing
What is a common, non-pathological cause of a slight notch/narrowing of the trachea at the very top of the CXR?
Solid fluid – white
Consolidation – often grey, patchy and with reticular/nodular pattern
How can you distinguish between infiltrate and solid fluid (usually external to lung tissue)?
Ribs fractures in multiple places creates a segment which won’t move – paradoxically “moves out” when breating in, and “moves in” when breathing out
What is flail chest?
How will healed rib fractures appear on CXR?
Fluffy densities on ribs. Seen on both ribs here:
How will healed rib fractures appear on CXR?
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