Session 8 - Radiology of the chest Flashcards
Which is ideal, a PA or AP chest xray? When is each done?
- PA (posterior to anterior) – Xray done when person is facing a wall and is ideal. This is because the heart is closer to the chest and if the Xray hits the heart first it would magnify it, in much the same way that a shadow puppet is magnified when closer to the source of light.
- AP (anterior to posterior) – Done when the patient is sitting down, usually because they are unable to stand. Inferior to PA. Can see the scapula in AP.
How do you use the trachea to align yourself in an chest X ray?
• Spinous process of the trachea should be in the middle of the ends of the clavicles. Otherwise there is tracheal deviation.
Why should the patient take a complete inspiration before taking the CXR? Where is the diaphragm located in a full inspiration CXR?
- Patient must take a full inspiration in so that the diaphragm can be located between the 5th and 6th intercostal space.
- If incomplete inspiration:
o Structures compressed upwards making heart look bigger and ribs closer
What is an artifact?
external or surgical material which obstructs the view
Label
What part of the heart is depicted in the left and right heart borders?
Left heart border is the left ventricle.
Right heart border is the right atrium.
Which hilar point is higher? What could the hilar points be used to indicate?
Left hilar points should always be above the right.
Collapse in the lung moves the hilar points
What is the carina and what can make it smaller?
Splitting of the bronchi. Angle is very important and can be made larger by a growth underneath e.g. growth of atria
What might loss of a silhouette of an organ indicate?
pathology
Give the ABC approach for assessing CXR.
- Adequacy
- Airway
- Breathing
- Circulation
- Diaphragm / Dem bones
How would you assess adequacy?
RIP
R – Rotation – Spinous processes at midpoint between medial ends of the clavicles?
I – Inspiration – Diaphragm found at 5th to 6th intercostal space?
P – Penetration – Spine visible behind the heart?
How would you assess airways in a CXR?
- Hila – check left hilum is above right
- Trachea – check trachea is central
How would you assess breathing in a CXR?
- Check the lungs, pleural spaces, lung interfaces.
- Are there any nodules? Consolidation? Calcification? Compare the 2 sides.
How would you assess circulation in a CXR?
Check the mediastinum:
o Aortic arch
o Pulmonary vessels with hila
o Right heart border – right atrium
o Left heart border – left ventricle and lingula interface (tongue of left lung)
How would you assess diaphragm / bones?
Check for free gas, nodules, fractures, and masses
What is a pneumothorax? What would be shown on an xray of a tension pneumothorax?
Air trapped in a pleural space Lung is black due to trapped air in chest
Trachea may deviate due to higher pressure
Depression of diaphragm due to pressure
Loss of lung markings
What is a pleural effusion? What would be shown on a CXR of a pleural effusion?
Collection of fluid in the pleural space
Uniform white area
Loss of costophrenic angle - angle at which diaphragm and chest wall meet
Obscured diaphragm
Visible meniscus
Mediastinal shift due to pressure
What are the 3 likely causes of lobar lung collapse?
Child - aspirated foreign material
>40 - cancer
Asthmatics - mucous plugging
What would be shown on a CXR of a lobar lung collapse?
Mediastinal shift towards collapse due to lower pressure
Elevation of diaphragm.
Define consolidation
Filling of the small airways / alveoli with stuff
What would be shown on a CXR of consolidation?
Dense opacification over the area with preservation of volume
What would cause a space occupying lesion? Give 3 things
Inflammation, malignancy, congenital
How would you identify cardiac enlargement on a CXR?
Cardiac index - Ratio of heart to thoracic cavity should be less than 50% on a PA image
Give the pathology of fibrosing alveolitis. What would be shown on a CXR? What would a lung function test reveal?
Increased activated alveolar macrophages which attracts neutrophils and eosinophils, resulting In lung damage due to ROS and proteases. Tissue destruction and fibrosis occurs. idiopathic
X-ray – Small lungs with micro-nodular shadowing predominating in the lower lobes with ragged heart borders
Lung function test shows reduced compliance and reduced gas transfer
What would a CXR of sarcoidosis reveal?
Miliary and nodular shadowing and diffuse fibrosis
Give 4 factors that would increase pleural fluid in the pleural space.
- Lymphatic obstruction
- Increased capillary permeability,
- Decreased oncotic pressure,
- Increased capillary venous pressure,
Give the terms for extra: a) blood b) chyle c) pus d) serous fluid in the pleural space.
a) haemothorax b) chylothorax c) empyema d) simple effusion
Define a transudate and an exudate
Transudate – Low protein content <30g/litre
Exudate - High protein content >30g/litre
Give 3 factors that would result in transudate pleural effusion
- Increased hydrostatic pressure e.g. cardiac failure
- Decreased oncotic pressure e.g. hypoalbuminaemia, nephrotic syndrome
- Increased capillary permeability e.g. sepsis
Give 3 factors that would result in exudate pleural effusion.
- Neoplasms – cancers producing pleural fluid
- Infection e.g. pneumonia and TB
- Immune disease e.g. connective tissue diseases
What 3 things can cause pleuritis?
- Infection e.g. TB and pneumonia
- Autoimmune
- Lung cancer – Tumours of the pleura can result in large pleural effusion
- Pneumothorax
What are the 4 symptoms of pleuritis?
- Sharp pain on inspiration
- Pain worse on coughing, sneezing, laughing etc.
- Involvement of diaphragmatic pleura results in Referred pain in shoulder
- Pleural rub – creaking noise heard on auscultation with respiratory movements
What 3 chest wall abnormalities might affect breathing?
• Deformation of ribs, sternum and thoracic spine •
Scoliosis and kyphosis may produce impairment of thoracic cage
• Trauma producing broken ribs, possible pneumothorax
How might muscle or neurological disease affect breathing?
- If muscles involved in breathing affected by generalised muscular diseases e.g. muscular dystrophy or MND
- Muscle weakeness produces resp failure with lower resistance to RTI due to poor clearance of secretions
