Normal Chest X Ray (Use Lecture CXR Images Alongside this to Identify Structures, Abnormalities etc.) Flashcards
Why might it be important to know of any allergies the patient has for a chest X ray ?
In case contrast agents are used
Why must the last menstrual period be known before performing a chest X ray ?
Because there is a real risk to the fetus if the woman is pregnant
What are the main indications of a chest X ray ?
- Acute deterioration in SOB
- Acute chest pain (e.g. MI, pulmonary oedema)
- Suspected malignancy
- Pneumonia
- Pleural disease (e.g. mesothelioma)
- Peritonitis
- Chronic lung disease
- Following invasive procedure (e.g. central line, chest drain)
Why would you perform a chest X ray following an invasive procedure ?
To ensure:
- Position of equipment (e.g. end of tube in the right place)
- no damage to patient (e.g. pneumothorax)
What position must the patient be in if an X ray is performed with suspicion of peritonitis ?
Erect for at least 10 mins pre image
What position are patients usually in when taking a chest X ray ?
Standing up, with arms either on sides, or around machine to move scapulae away to have better look at lung fields
Why do we prefer the patient to be standing up for a chest X ray ?
Because want any air in pleural and abdominal cavity to rise up, fluid in pleural cavity to go down to the bottom
Are most chest X rays performed in PA or AP ?
PA
What is the main advantage of PA over AP images ?
May comment on size of the heart in PA images, not in AP images
What is the main reason an AP image might be performed rather than a PA image ?
Because the patient is unwell
What are some technical factors which MUST be done right in order for the X ray to be valid ?
1) Erect rather than supine
2) Full breath in (inspiration)
3) Right orientation (R on image really the R of the patient and same for the L)
4) Penetration (well-exposed)
5) Rotation (patient square onto the film)
6) PA or AP (PA able to comment on size of heart)
How may you decide if the patient has had a good inspiration based on the chest X ray image ?
If taken with full breath in, should cover 5 to 6 ribs anteriorly
How can you decide if the penetration of an X ray image is good (if it’s well-exposed) ?
By ensuring that you see the intervertebral spaces behind heart shadow
What does it mean when a chest X ray is said to be under-exposed ? What patients may you encounter this in (often) ?
“Cardiac shadow is opaque, with little or no visibility of the thoracic vertebrae. Lungs appear denser and whiter”
Tends to happen more with obese patient due to Doctor underestimating obesity of patient
What does it mean when a chest X ray is said to be over-exposed ?
“Heart becomes radioluscent and lungs become darker”
How can you check whether the rotation of the patient on the X ray is good ?
Ends of clavicle equidistant and crossing spines of thoracic vertebrae
Give an example where one may have to work with poor rotation upon taking a chest X ray.
Patient with scoliosis
What are possible causes of a chest X ray image being too black or black in the wrong place ?
- Air (e.g. free gas under diaphragm due to perforated disk or laparoscopy)
- Loss of tissue density (e.g. bony metastasis)
What are possible causes of a chest X ray image being too white or white in the wrong place ?
- Fluid (e.g. too much fluid in pleural space i.e. pleural effusion or fluid in pulmonary cavity i.e. pulmonary oedema)
- Increased tissue e.g lymphadenopathy, TB
What is it called when a chest X ray image if too black or black in the wrong place ?
Increased tranlucency
What is it called when a chest X ray image if too white or white in the wrong place ?
Opacification
What are possible causes of really, really white or very radio opaque elements on a chest X ray ?
Pacemaker ETT Nasogastric tube Sternal wiring Prosthetic heart valves Central Veinous Pressure line Chest drain
Identify the main “things” to look at when looking at a CXR.
First and foremost, answer the question you have (e.g. does this man have a fracture anywhere ?). Then,
A Airway B Breathing C Cardiac (heart) D Diaphragm E External Structures & Equipment F Fat and soft tissue G Great vessels H Hidden areas
Describe some of the features to be looking for when checking the Airway on a CXR.
- Trachea should be straight and black (starting at C6)
- Carina at T4
- Right main bronchus more vertical, wider and shorter than left main bronchus
Identify possible abnormalities in the airway on a CXR.
- Endotracheal tube too close to the carina (i.e. needs to be withdrawn)
- Mediastinal shift (i.e. trachea moves to one side)
- Angle of the bronchi increased by pressure from enlarged lymph nodes (Sarcoid, Tumour) or by local tumour.