Chest X-rays Flashcards
What are X-rays?
- Diagnostic tool in medicine and dentistry
- Images produced by passing a certain wavelength of radiation through an object
White: radiopaque or radiodense
(The greater the density of the object, the less the penetration of the x-rays through it)
Black: radiolucent
(The less dense object allows more x-rays to penetrate it)
What colour do bones show up on an X-ray?
White
What colour does water show up on an X-ray?
White/grey
What colour does fat show up on an X-ray?
Grey/white
What colour does air show up on an X-ray?
Black
What colour does metal show up on an X-ray?
White
What view is ‘AP’?
Anteroposterior
What view is ‘PA’?
Posteroanterior
Describe posteroanterior (PA) view of X-ray.
- Beam passes through the chest from back to front
- Patient must stand whilst CXR is taken
Describe the anteroposterior (AP) view of X-ray.
- Beam passes through the chest from the front to the back
- Portable CXR’s performed at patients bedside are AP
Why is Posteroanterior (PA) view of X-ray preferred over Anteroposterior (AP)?
- Structures in the anterior part of the chest appear larger (i.e heart due to magnification)
- Potential interference in image from scapulae
- Could lead to incorrect diagnosis of cardiomegaly
Why would a lateral view X-ray be done?
- May reveal lesions behind the heart near the mediastinum or near the diaphragm
- Together with a frontal view, the lateral can provide a 3-D view of the chest
What is the systemic approach to X-rays?
Check:
- Patient’s first and last name, dob, hospital number
- Note X-ray time and date
- Note the view/projection: PA, AP or lateral (departmental films are PA, portable films are AP)
- Ensure the X-ray is the right way round
Exposure:
- Over exposed appears too black while under exposed appears too white
- Check exposure: if good the vertebral bodies should be visible throughout upper but not lower heart shadow
What does ABCDEF stand for in X-ray?
A: Airway
B: Bones
C: Cardiac
D: Diaphragm
E: Everything/Exposure (soft tissue, lines/airways)
F: Fields
What do you need to consider about airways in an X-ray?
Trachea:
- Position: displaced?
- Black: air should be present
- ET tube or tracheostomy
- Carina and Right Left Main Bronchus as they divide from trachea
Where do the ribs sit on full inspiration in an X-ray?
The midpoint of the right hemidiaphragm lies between:
- The 5th – 7th ribs anteriorly
- The 8th – 10th ribs posteriorly
What do you need to consider about bones in an X-ray?
- White: due to denseness
- Alignment of clavicles
- Count Ribs:
~ Hemidiaphragm should be between the 5th and 7th rib anteriorly
~ 10 posterior ribs visible
~ 6 anterior ribs visible
~ Rib crowding - Spinal Alignment: any sign of scoliosis
What are the bones of the thoracic cage that will show up on an X-ray?
- Clavicular level
- Rib markings (check for fractures)
- Identify the scapula borders (sometimes mistaken for a pneumothorax)
- Vertebral and spinous processes
What are the soft tissues of the thoracic cage that will show up on an X-ray?
- Breast shadows
- Surgical emphysema under the skin
What do you need to consider about cardiac wise in an X-ray?
Positioning, Size & Shape:
- 1/3 right of spine
- 2/3 left of spine
Aortic Notch Visible:
- ? LUL collapse or consolidation
Hilar Markings:
- Left will be slightly higher due to left main pulmonary artery
Borders (silhouette sign):
- Indicative of right middle lobe collapse/consolidation
What are the (2) normal heart contours that will show up on an X-ray?
Left heart contour:
- Left lateral border of Left Ventricle (LV)
Right heart contour:
- Right lateral border of the Right Atrium (RA)
What is the costophrenic angle?
Angle formed by lungs & ribs
What is the costophrenic angle obliterated by?
- Meniscus of small pleural effusion –> (200 ml. of fluid needs to accumulate in the pleura before blunting the costophrenic angle)
- Patchy shadowing of consolidation
- Chronic atelectasis
- Lung hyperexpansion (pushes diaphragm domes down, rounding the angle)
What are examples of artefacts which will show up on an X-ray?
- Endotracheal Tube
- Tracheostomy / Mini-trach
- Nasogastric tube
- ECG leads
- Central line
- Chest Drain
- Other
