19-09-22 – Interpretation of Normal Chest X-Rays Flashcards
1
Q
Learning outcomes
A
- Appreciate how anatomical structures appear on the chest x-ray (CXR)
- Learn how important technical factors alter the overall appearance of the CXR
- To learn a strategy for the interpretation of CXR
- Appreciate all clinicians must be able to read a CXR
2
Q
What is it important we fill out on the imaging GP request form?
Where are images sent to?
A
- It is important we fill in clinical history/findings and what question do you want this test to answer
- It gives the radiographer an indication of what you are looking for
- It is important we fill in last menstrual period (LMP), as x-rays should be taken within 20 days of the last LMP
- Images are sent to PACS to be interpreted (picture archiving communication system)
3
Q
What are 8 reasons we might want to ask for a chest x-ray?
A
- Reasons we might want to ask for a chest x-ray
1) Acute deterioration in SOB (shortness of breath)
2) Acute chest pain
3) Suspected malignancy
4) Pneumonia (covid)
5) Pleural disease (mesothelioma)
6) Peritonitis (erect for at least 10 mins pre image)
7) Chronic lung disease
8) Following invasive procedure e.g. central line, chest drain
4
Q
3) What are the 6 basics we look for when taking a chest x-ray?
A
- Basics we look for when taking a chest x-ray:
1) Correct patient (2-point ID e.g name and CHI number)
2) Correct date of the radiograph (are there any other radiographs to compare to?)
3) PA or AP?
4) Exposure
5) Rotation
6) Correct orientation
5
Q
Why are PA x-rays preferred?
How are they done?
When might AP x-rays be used?
A
- Posterior to anterior (PA) or anterior to posterior (AP)
- Erect PA is the most used
- These images give a higher quality, and have a more divergent beam to cover the same anatomical field, as the x-ray beam till diverge from source until the x-ray film
- PA x-rays allow for the size of the heart to be commented on
- In order to take a PA view, the patient places his or her arms around the side of the detector plate or stands with hands on hips. This ensures the scapulae are rotated laterally and no longer overlap the lungs.
- The patient is asked to take a few deep breaths and hold it for a couple seconds, with the chest x-ray being taken on full inspiration
- If patients are too unwell to tolerate standing for an erect PA x-ray, a supine AP film can be taken
6
Q
Other views. Lateral Chest X-ray and Expiratory film
A
7
Q
Why is orientation in an X-ray important?
What is dextrocardia?
A
- Orientation in an x-ray is important we must ensure the sides of the x-ray film are correctly labelled
- Dextrocardia is when the heart is positioned on the right side instead of the left
- Dextrocardia on its own doesn’t cause problems, but it tends to occur with other conditions that have serious effects
8
Q
What does a an underexposed, well-exposed/well penetrated, and over-expose x -ray look like?
A
- An underexposed x ray (soft) looks too white, and happens more often because of obesity
- A well exposed/well penetrated x-ray is one in which the individual vertebrae and spinous process are just visible behind the heart
- An over-exposed (hard) x -ray is too dark
9
Q
What do we want in terms of rotation of an x-ray?
A
- In terms of rotation of an x-ray, we want to ensure the patient is straight on the film
- We want the clavicles to be equidistance from the midline
10
Q
What might we be looking for if tan x-ray area is too black/black in the wrong place?
What about if the x-ray area is too white/white in the wrong place?
What if the x-ray area is very white/opaque (cloud)?
A
- If the x-ray area is too black/black in the wrong place, there is increased translucency, meaning there may be air (gas) or loss of tissue density
- If the x-ray area is too white/white in the wrong place, this indicates opacification (become cloudy), meaning there may be fluid or increased tissue (swelling of lymph nodes)
- If the x-ray area is very white, or very opaque (cloud), we think hardware:
1) Pacemaker
2) ETT (exercise tolerance test)
3) NG tube (nasogastric)
4) Sternal wiring
5) Prosthetic heart valves
6) CVP (central venous catheter)
7) Chest drain
11
Q
What are the 8 parts of the systemic approach to searching a CXR?
A
- 8 parts of the systemic approach to searching a CXR:
A) Airway
B) Breathing
C) Cardiac (heart)
D) Diaphragm
E) External structures and equipment
F) Fat and soft tissue
G) Great vessels
H) Hidden areas
12
Q
What are we looking for when we check Airway (A) on a CXR?
What pathologies might we be checking for?
A
- Checking Airway (A) on a CXR:
- Check if trachea is straight, which is darker, as it contains air
- Aim to see carina around T4
- Pathologies:
- Right main bronchus is more vertical, wider and shorter than the left main bronchus
- This means foreign objects are more likely to go down the right main bronchus
- Narrowing of the airway can indicate oedema or stenosis (narrowing)
- In a tension pneumothorax the airway will be deviated from the affected side
- In kids, airway should be straight, in adults, it can be deviated to the right due to aortic arch
13
Q
What are we looking for when we check Breathing (B) on a CXR?
What pathologies might we be checking for?
A
- Checking Breathing (B) on a CXR:
- Check expansion
- Anterior 6th rib should cross dome of the right hemi-diaphragm
- Chest x-ray is taken at full inspiration
- We want to look at apices of lungs and vessels
- The opacity will increase from top to bottom, and there is diminution of lung markings as we move more lateral, so vessels will be more prominent in the medial lower lung
- Right lung has 3 lobes, left lung has 2 lobes
- When we talk about lungs, it is difficult to pin point the correct lobe, so we use upper, middle, and lower zones
- Pathologies
- Under-expansion may be caused be shortness of breath/pain
- Over-expansion may be caused by lung pathology
14
Q
What are we looking for when we check Cardiac (heart – C) on a CXR?
What pathologies might we be checking for?
Label the margins of the heart
A
- Checking Cardiac (heart – C) on a CXR:
- On a PA x-ray we can measure the size of the heart
- It should be less than 50% of the diameter of the chest
- 1/3rd of the heart should be present visible to the right of the sternum, with the other 2/3rd of the heart visible to the left of the sternum
- We look at the margins and borders of the heart
- Pathologies:
- Dextrocardia is when the heart is positioned on the right side instead of the left
- Dextrocardia on its own doesn’t cause problems, but it tend to occur with other conditions that have serious effects
- An undefined right boarder of the heart suggests middle lobe lung consolidation and a poorly defined left boarder suggests lingula (tongue like projection in upper lobe of left lung) lung consolidation.
- Lung consolidation occurs when the air that usually fills the small airways in the lungs is replaced with something else
15
Q
What structures make up the 5 borders of the heart
A
16
Q
What are we looking for when we check the Diaphragm (D) on a CXR?
What pathologies might we be checking for?
A
- Checking Diaphragm (D) on a CXR:
- The right hemi-diaphragm is usually one rib higher than the left
- Identify the gastric bubble – rounded area nestled under left hemi-diaphragm
- Pathologies:
- Look below the hemi-diaphragms for air from a perforated viscus (intestinal/bowel perforation)
- Pathologies
- Highest point of left diaphragm should be just lateral to the middle of the lung, and the highest point of the right diaphragm in the middle of the right lung
- Deviation to one side can indicate pneumothorax
17
Q
What are we looking for when we check the External structures and equipment (E) on a CXR?
A
- Checking External structures and equipment (E) on a CXR:
- Looking at bones (sternum not visible on frontal x-ray):
1) Ribs
2) Thoracic spine
3) Clavicles
4) Scapulae
5) Humeral heads - Looking at medical devices:
1) Oxygen tubing
2) Pacemaker/heart valves/sternotomy wires
3) Chest trains
4) NG tube
18
Q
What are we looking for when we check the Fat and soft tissues (F) on a CXR?
What pathologies might we be checking for?
A
- Checking Fat and soft tissues (F) on a CXR:
- Will be grey/white
- Looking for breast shadows
- Pathologies
- Examine subcutaneous fat for signs of subcutaneous (aka surgical) emphysema
- Subcutaneous emphysema is when the inner walls of lungs’ air sacs (alveoli) are damaged, causing them to eventually rupture – causes shortness of breath
- Pneumomediastinum (aka mediastinal emphysema) is a condition in which air is present in the mediastinum
- Pneumomediastinum can be caused by trauma injury, or other conditions, such as pneumothorax
19
Q
What are we looking for when we check the Great Vessels (G) on a CXR?
What pathologies might we be checking for?
A
- Checking Great vessels (G) on a CXR:
- Looking for aortic arch, pulmonary arteries and veins in the mediastinum
- Left hilum is usually slightly higher than right hilum
- Pathologies
- Look for calcium deposits in the elderly
- Increased in opacity of hilum may be indicative of liquid in the system or infection
20
Q
What are we looking for when we check Hidden areas (H) on a CXR?
What pathologies might we be checking for?
A
- Checking Hidden areas (H) on a CXR:
- Check this after going through ABCDEFG twice
- Hidden areas/commonly missed areas:
1) Neck
2) Apices
3) Mediastinum: widening, adenopathy (swelling of chemical releasing glands), mediastinal emphysema (air present in mediastinum)
4) Behind the heart
5) Costophrenic angle – formed by the points where the chest wall and diaphragm meet. Blurred costophrenic angle could indicate pleural effusion (liquid gathering in pleural space, sometimes called water on the lungs)
6) Behind/below diaphragm
7) Soft tissues
8) Bones – check bone density
