09-11-22 – Understanding the Abnormal Chest X-Ray Flashcards
Learning outcomes
- Review the basic “admin” needed before considering an x-ray.
- Consider why imaging has been requested
- Learn a structured approach to the analysis of a CXR
- Start to recognise patterns of abnormalities
What are the first 5 things we check when analysis an x-ray?
- 5 things we check when analysing an x-ray:
1) Correct patient (2 points of ID)
2) Correct date of radiograph (including correct historical dates)
3) PA vs AP; Oriented correctly (left/right)
4) Exposure/Penetration
5) Rotation
What are the 5 different x-ray densities?
- 5 different x-ray densities:
1) Air/gas: black,
* e.g. lungs, bowel and stomach
2) Fat: dark grey,
* e.g. subcutaneous tissue layer, retroperitoneal fat
3) Soft tissues/water: light grey,
* e.g. solid organs, heart, blood vessels, muscle and fluid-filled organs such as bladder
4) Bone: off-white
5) Contrast material/metal: bright white.
What are 7 examples of things that appear bright white on a chest x-ray?
- 7 examples of things that appear bright white on a chest x-ray (artefact/metallic):
1) Pacemaker
2) ETT
3) NG tube
4) Sternal wiring
5) Prosthetic heart valves
6) CVP line
7) Chest drain
What 4 things do we have to consider when analysing a CXR?
- 4 things we have to consider when analysing a CXR:
1) Pre-test question (reason for doing CXR)
* Is there pneumonia? Is there a cancer?
2) Consider history, signs, other factors
* Was there fever, cough and dirty phlegm? Weight loss & haemoptysis? (Coughing blood)
3) Consider the immediate answer to the pre-test question
* Multifocal cavitating lesions; large mass lesion
4) Review systematically the rest of the film
* Associated pleural effusion (empyema?); associated pleural effusion (malignant?)
What are the 8 parts of the systemic approach to searching a CXR?
- 8 parts of the systemic approach to searching a CXR:
1) Airway
2) Breathing
3) Cardiac (heart)
4) Diaphragm
5) External structures and equipment
6) Fat and soft tissue
7) Great vessels
8) Hidden areas
Why do we want to check an ET tube on an x-ray?
What is the difference between pneumothorax, collapsed lung, and atelectasis?
Why do certain pathologies pull/push the trachea away?
What are 2 pathologies where the trachea is deviated away from the pathology?
What are 4 pathologies where the trachea is deviated towards the pathology?
How do they each affect the colour of the x-ray?
- We want to check an ET tube on an x-ray to make sure it is high up enough to ventilate both lungs
- A pneumothorax means air in the pleural space (between visceral and parietal pleura), it doesn’t tell us anything about the state of aeration of the lung
- Atelectasis is loss/reduction in inflation of the lung due to lobar/alveolar collapse
- Collapsed lung is a term for complete atelectasis of the lung
- These terms can be mutually exclusive
- We can have a collapsed lung with or without pneumothorax
- We can have a pneumothorax with or without a collapsed lung
- Pathology that decreases the pressure in one hemithorax will ‘pull’ the trachea towards it.
- Pathology that increases the pressure of a hemithorax will ‘push’ the trachea away from it.
- Pathologies where the trachea is deviated away from the pathology:
1) Pneumothorax (too black on x-ray) – air in pleural cavity
2) Pleural effusion (too white on x-ray) – fluid in pleural cavity
- Pathologies where the trachea is deviated towards the pathology (all too white on x-ray)
1) Pneumonectomy - surgical removal of a lung
2) Lobectomy – removal of lobe of lung
3) Lobar collapse (atelectasis)
4) Fibrosis
What are clinical signs of pneumothorax/collapsed lung in:
* Inspection (6)
* Expansion (1)
* Percussion (2)
* Auscultation (1)
* Vocal fremitus (1)
- Clinical signs of pneumothorax/collapsed lung in:
- Inspection
1) Sharp, stabbing chest pain that worsens when trying to breath in.
2) Shortness of breath.
3) Bluish skin caused by a lack of oxygen.
4) Fatigue.
5) Rapid breathing and heartbeat.
6) A dry, hacking cough. - Expansion
1) This build-up of air puts pressure on the lung, so it cannot expand as much as it normally does when you take a breath - Percussion
1) Dull percussion notes for collapse
2) Hyper-resonant percussion notes for pneumothorax - Auscultation
1) In pneumothorax and lung collapse, breath sounds are diminished to absent - Vocal fremitus
1) Decreased vocal fremitus for pneumothorax and collapse
What is B for in analysing X-rays?
What is consolidation?
What needs to happen when we see consolidation?
What is an air bronchogram?
What are 5 different causes of consolidation?
What is an example of when we might see each cause (in picture)?
How does lung volume change on consolidation?
- B is for breathing in the analysis of X-rays
- Consolidation is a pathological diagnosis that means replacement of normal air-space (gas) with fluid or solid
- When we say we’ve seen consolidation, we need to have seen a radiographic representation of it, which would normally be an air bronchogram
- Air bronchogram refers to the phenomenon of air-filled bronchi (dark) being made visible by the opacification of surrounding alveoli (grey/white), as those seen in consolidation
- The large airways are spared so become visible (black) against the white background
- Lung volume does not change in consolidation
How will consolidation present in terms of:
1) Percussion
2) Vocal resonance
3) Auscultation
- How will consolidation present in terms of:
1) Percussion
* Dull to percuss
2) Vocal resonance
* Increased vocal resonance
3) Auscultation
* Increased auscultation/breath sounds = Bronchial breathing
Compare these 2 x-rays
- Comparing these 2 x-rays:
1) Left CXR:
* In terms of opacification – ill-defined area of opacification adjacent, but not continuous with the left heart border.
* The costophrenic and cardiophrenic angles are clear.
2) Right CXR
* More clearly defined wedge-shaped area of homogenous opacification on the left side, which is continuous with the left heart border.
3) From an anatomical perspective the key feature is the left heart border and whether it is visible.
* On the left, it can be clearly seen, but not on the right – therefore the radiograph on the right involves consolidation in the lingula, whereas the radiograph on the left shows left lower lobe consolidation.
How do we describe the location of an abnormality?
- When describing the area of an abnormality, we used zones
Compare these 2 x-rays
- Comparing these 2 x-rays
1) On the left
* Hazy opacification, obscuring the right heart border – suggesting right middle lobe consolidation.
2) On the right
* Well-defined triangle of opacification in the upper right lung – RUL collapse
* We can’t see any air bronchograms, so we are thinking that part of the upper lobe is collapsed instead of consolidated
What is atelectasis?
What is a collapsed lung?
In what 6 situations would we suspect atelectasis?
- Atelectasis is Reduction in inflation of all or part of the lung due to lobar/alveolar collapse
- Atelectasis of the full lung is a collapsed lung
- 6 situations would we suspect atelectasis:
1) Volume loss
2) Displacement of trachea
3) Displacement of diaphragm – pointy middle of diaphragm called tenting, which indicates loss of volume
4) Displacement of lung fissures
5) Compensatory overinflation of non-collapsed lung
6) Crowding of vessels & bronchi
What is the veil of left upper lobe collapse/atelectasis?
What causes this?
How is it characterised?
- A characteristic of left upper lobe collapse is the ‘veil’ of LUL collapse/atelectasis
- This is due to a lesion that has collapsed the left upper lobe and moved it forward, impairing the penetration of the x-rays, and leading to the veil of LUL collapse/atelectasis
- This is where there is elevated left hemi diaphragm and loss of cardio-mediastinal contour
- There also causes an even graininess over the left side
What can opacification be other than collapse/consolidation?
What are 3 characterizations of pleural effusion?
What 2 things do we have to do after diagnosing pleural effusion?
- Opacification can also be pleural effusion (fluid in pleural cavity), not just collapse/consolidation
- Pleural effusion can be characterized as having:
1) Trachea pushed away
2) Zone uniformly white (left lower zone on diagram)
3) Meniscus - 2 things do we have to do after diagnosing pleural effusion? :
1) Look for the primary diagnosis, as pleural effusion is often a secondary diagnosis
* Review history/exam for clues
* Visible on both sides suggests systemic issue (eg.CCF – congestive heart failure)
* Large, unilateral, in elderly, think cancer until proven otherwise
2) Sample the effusion by carrying out a diagnostic tap
* Exudate (high protein) - consider infection, cancer, inflammatory eg. RhA
* Transudate (low protein) – consider systemic causes eg.CCF, liver, renal
15) What are characterisations of asbestos exposure?
Are pleural plaques dangerous?
What are we most concerned about with asbestos exposure?
- The main characterisations of asbestos exposure are calcified pleural plaques
- The straight lines seen from the plaques are so straight and defined that we can tell its pleural based (shown on the left x-ray)
- On the x-ray on the right, the pleural plaques are not calcified and may be confused them with metastases, so we have to do a CT to confirm
- Pleural plaques are not pathological, but are simply scars that indicate potential pathology
- Calcified pleural plaques don’t themselves require any intervention
- Most concerning thing is pleural cancer aka mesothelioma (pleural effusion, thickening)
How does a small pneumothorax appear on an x-ray?
What is the ABCDE for cardiac?
- ABCDE for cardiac (below signs not specific for cardiac failure):
1) A – Alveolar oedema
* Bats wings shape: bilateral peri-hilar shadowing
* This occurs early on in oedema
2) B – Kerley B lines
* Thickened interlobular septa, due to connective tissue oedema
* Not diagnostic of cardiac failure, but consistent with it
3) C – Cardiomegaly (enlarged heart)
* Can’t judge heart on AP scan (like given in this diagram)
* Shouldn’t be more than half of the width across on a PA scan
4) D – Diversion of upper lobe blood vessels
* Due to high atrial pressure
5) E – effusions (usually bilateral)
* Costophrenic angles aren’t sharp as they should be due to effusions
What is pulmonary oedema a mix of?
What does it result from?
What are 3 characteristics of pulmonary oedema?
- Pulmonary oedema is a mixture of interstitial and alveolar oedema, so there is excess fluid within both the airways and the interstitium.
- It results from increased hydrostatic pressure, due to cardiac failure
- 3 characteristics of pulmonary oedema:
1) Bat wing appearance
2) Kerley B lines
3) Cardio-thoracic ratio (PA only – heart shouldn’t be more than half of width)
Label these structures
What are we checking for with the diaphragm?
What does the patient have to do prior to the scan to check for this?
Why is this?
- When checking the diaphragm, we are trying to see if there is air under the diaphragm due to perforation of an abdominal organ
- To accurately establish if there has been a perforation, then the x-ray must be taken ‘erect’.
- This means that the patient has to sit upright for 15-20 minutes prior to the x-ray being taken – not easy if you are in pain.
- This allows the air to rise within the peritoneal cavity and then be seen on the x-ray.
What are we checking for with external structures?
What does external refer to?
- With external structures, we are checking for hardware and bones
- External refers to outside of the lungs, so the ribs and shoulders in particular
What are we looking for in Fat and soft tissues?
- In fat and soft tissues, we are also checking the breasts
- The image on the left has two breast shadows present.
- The image on the right shows a patient with a left-sided mastectomy
What are we checking for with great vessels?
- With great vessels, we are checking to see the position and prominence of the great vessels
- If they are more prominent than usual, this can indicate hypertension
What are the 8 hidden areas that are commonly missed?
- 8 Hidden areas that are commonly missed:
1) Neck
2) Apices
3) Mediastinum: widening, adenopathy (large or swollen lymph glands)
4) Behind the heart
5) Behind / below diaphragm
6) Costophrenic angles
7) Scan across the CXR for pneumothorax
8) Bones
When we see bilateral hilar lymphadenopathy, what 3 things should we suspect?
What should we suspect if its unilateral?
- 3 things should we suspect when we see bilateral hilar lymphadenopathy:
1) Sarcoidosis
* Inflamed cells clump together to make small lumps called granulomas.
2) TB
3) Lymphoma (Hodgkin’s)
- If its unilateral, we should suspect cancer
Label all the structures shown on this x-ray.
What could have caused all of this?
What is surgical emphysema?
- This may have all been caused through a placement of a central line without checking the patient’s history
- This may have caused a pneumothorax, which can cause widespread surgical emphysema
- With the placement of more drains, these worsened
- Subcutaneous (or surgical) emphysema is the presence of gas in the subcutaneous soft tissues, which may be detected clinically by swelling of the affected area and crepitus on palpation
