Imaging of the thorax Flashcards
What is computed tomography?
- an X-ray applied as a single beam
- then quickly rotated around the body
What type of rays does computed tomography use?
- ionising radiation
- downside of CT
Everyone experiences some form of background radiation during routine day to day activities. What is the equivalent dosage from a CT scan?
- 1 years worth of radiation on a chest scan
Are CT scans accessible and expensive?
- cheap
- accessible
Do CT scans provide 2D or 3D images?
- 3D cross sectional
Why is it difficult to detect specific tissue and abnormalities in CT imaging?
- images are superimposed on top of each other
- this makes it hard to detect things in its own anatomical space
Why is ultrasound used so commonly in clinical proactice?
- cheap and accessible
- non ionising
What is the biggest flaw of ultrasound?
- operator dependent
What is radionuclide imaging?
- a radioactive dye is inserted into the body
- may be specific to a tissue or organ
- the dye can be detected on the imaging modality
When using CT scans, why is reformatting important?
- aspects of images can be edited to enhance clarity
Why is injecting patients with contrast a good thing?
- contrasts show up on images better
- allows abnormalities to be identified better
When looking at images, which side is left and right?
- looking at the image the right = left
- left = right
- unless stated otherwise
Instead of performing an operation blindly, what imaging technique may help with this?
- ultrasound
Is X-ray or ultrasound better at detecting pleural effusions?
- ultrasound
- X-rays are pass straight through fluid
What is echocardiogram?
- ultrasound imaging
- used to identify cardiac and vascular structural changes
What is the normal direct a chest X-ray is performed?
- from back to front
- postero-anterior (PA)
When would you change from a postero-anterior chest X-ray to an anterior-posterior X-ray?
- if the patient is unable to stand alone
When analysing an X-ray what is one of the first things to check?
- was the patient aligned centrally in the image
- any annotations on the image align with?
What checking to see if a patient has inspired on an X-ray, where should the 6th anterior rib align with?
- cross the diaphragm at the mid clavicular line
When analysing an X-ray, what do each of the following words represent? ‘ Are There Many Lung Lesions Present’
- Are = Abdomen
- There = Thorax
- Many = Mediastinum
- Lung - Lung (right and then left)
- Lesions = Lungs comparison
- Present = Devices
What are some common artefacts that can show up on an X-ray?
- bra-straps
- ECG leads
- pacemakers
On X-rays a gas bubble can be present on the left side, just above the diaphragm. Why is this normal?
- this is the stomach
- the stomach contains air
In a normal healthy X-ray what should the length of the mediastinum be roughly half of or less?
- the thorax
If the width of the mediastinum is greater than half of the thorax, what does this indicate?
- patient has an enlarged heart
What is the cardio thoracic ratio?
- width of mediastinum is compared with thorax
If a patient has a feeding tube that is supposed to go to the stomach, but accidentally it enters the trachea, where is it like to be lodged?
- on right primary bronchi
- right aligns with trachea better at the carina
When inserting a feeding tube for a patient, that is then check on an X-ray, how would you know this is in the correct place?
- tube should cross the diaphragm at the midline
- tube visible below the left hemisphere of diaphragm
- tube dissects the carina
- tube follows oesophagus and not trachea
