Flashcards in Chest X-rays Deck (21):
What colour is: gas, fat, liquid, soft tissue, calcification and metal on an x-ray?
Any gas is black
Fat is more grey
Liquid – white
Soft tissue – white
Calcification – white
Bone – white
Metal – bright white
What is the projection of an X-ray?
PA projection – X-rays come through the back (posterior – anterior)
AP Projection – done from the front – will say (anterior – posterior)
Why is a PA X-ray preferable?
In PA – little divergence from the heart to the reader but in AP there is much more divergence and heart looks much bigger so can’t observe the heart, same with other organs and structures.
What should a good chest x-ray have in it?
• Must include: first rib, lateral margin of ribs and costophrenic angle.
• Have little rotation – alignment of spinous process and clavicles.
• Lung volumes – X-ray taken when patient fully breathes in. Lung volume is normal if 5th to 7th anterior ribs are at the mid clavicular line. Issue with incomplete inspiration on radiograph is that the heart may look bigger and there will be increased lung markings. If there is exaggerated expansion, then this could look like an OAD.
• Penetration – Degree to which the X-rays have passed through the body – with adequate penetration the vertebrae should just visible through heart, complete left hemidiaphragm is visible. Digital manipulation often negates this.
What artifacts are commonly seen on X-rays?
Hair, clothes, button, nipple piercings, pace makers and surgical/vascular lines.
Describe what you should see normally on an X-ray?
Trachea – should be central (unless rotated)
Hilar – left always higher than right. Hilar point where the bronchi split.
Aortic knuckle – should be a small protrusion coming from the spine above the heart into the left lung field
Pleura lining the fissures – effusions and tumours can occur within the fissures
Costophrenic and cardiophrenic angles – sharp and pointy – if not probably a bit of fluid.
Normal stomach bubbles
Soft tissue – nipple markings bilateral and symmetrical not anything pathological
Describe the DR ABCDE method of evaluating chest X-rays
Demographics – looking at right patient – age, sex, name, date and whether it is PA/AP
RIPE – Rotation (clavicles and spinous processes of vertebrae aligned – usually there is a minimal amount of rotation, Inspiration – 5-7 anterior ribs or 8-10 posterior ribs – too ribs = hyperinflation (COPD) – too few = inadequate inflation making the heart look bigger than it is, Picture – can see everything we want to and Exposure – spinous processes through the heart – over exposed = too dark and under exposed = too white.
Airway – looking for deviation of airway (may be rotation). Trachea, bronchi and hila in correct place
Breathing – lungs, pleural spaces and lung interfaces, opacification and lucency
Circulation – mediastinum, aortic arch, pulmonary vessels, right heart border (looking at right atrium and middle lobe interface), cardio thoracic index and left heart border (looking at left ventricle and lingual interface)
Diaphragm – costophrenic angles and cardiophrenic angles flattened diaphragm indicate hyperinflation
Everything else – free gas, nodules, fracture/dislocation and masses.
What could an Opacity that you see on a chest X-ray be?
Opacity – pleural effusion, consolidation or collapse (which is usually also present with decreased volume such as tracheal deviation).
If you still can't find anything on a chest X-ray what else should you check?
• Apices looking for small pneumothorax
• Thoracic inlet looking for masses
• Paratracheal stripe looking for masses and swollen lymph nodes
• Lymph nodes
• Behind heart looking for a mass
• Below diaphragm looking for pneumoperitoneum or a mass
What are silhouette signs?
Adjacent structure of differing density form crisp silhouettes. E.g. the Heart next to the lung is white next to black. Loss of the contour can locate a pathology.
Give some examples of silhouette signs
• Right heart border - Right Middle Lobe.
• Left heart border - Lingula.
• Paratracheal stripe - mediastinal disease.
• Chest wall - lung pleura/rib.
• Aortic knuckle - Anterior mediastinum/left upper lobe.
• Diaphragm - lower lobe.
• Horizontal fissure - Anterior segment upper lobe.
What are the 2 reasons for the mediastinum to shift?
Push = increase volume or pressure.
Pull – decrease volume or pressure.
What is the key to locating a pneumothorax?
Clear pleural edge with no lung markings beyond that
What does a pleural effusion look like on a chest X-ray?
Collection of fluid in the pleural space, uniform white area, loss of costophrenic angle, hemidiaphragm obscured and meniscus at upper border. Beware of the supine CXR.
What is atelectasis, what are it's causes and how will it appear on an X-ray?
Lobar lung collapse
Volume loss within the lung lobe
Causes: luminal – aspirated foreign material, mucous plugging or iatrogenic (due to treatment)
Mural – bronchogenic carcinoma
Extrinsic – compression by adjacent mass
Generic findings, elevation of the ipsilateral (same side of the body) hemidiaphragm, crowding of the ipsilateral ribs, shift of the mediastinum towards the side of atelectasis and crowding of the pulmonary vessels.
What is consolidation, how does it appear on a chest X-ray and what is the difference between LRTI and Pneumonia in an x-ray?
Filling of small airways/alveoli with: pus – pneumonia, blood – haemorrhage, fluid – oedema and cells – caner.
Dense opacification, volume preserved, air bronchogram (air filled bronchus made visible by white alveoli due to consolidation).
LRTI = no radiological abnormalities
Pneumonia = radiological abnormalities
What are the causes of space occupying lesions and what can it mimic?
Causes – malignant primary or metastatic, benign mass lesion, inflammatory, congenital
Mimics – bone lesions, cutaneous lesion and nipple shadow.
Nodule < 3cm
Mass > 3cm
How do you measure the cardiac index?
Cardiac Index – heart width less than 50% of thoracic width.
How does pulmonary oedema present on a chest x-ray?
Pulmonary oedema will present with certain radiological signs:
B lines – kerley B lines interstitial oedema
Dilated prominent upper lobe
How does consolidation differ between pneumonia and TB?
Pneumonia is generally present in the bottom zones of the lungs whilst TB is uauly in the top two and doesn’t look quite normal.