4: Radiology - imaging modalities, advantages & disadvantages Flashcards
Which radiography method would be used to obtain a simple image of the heart?
Chest X-ray
Give three different types of angiogram.
Catheter angiogram
CT angiogram
MRI angiogram
Which imaging modality is used to obtain an echocardiogram?
Ultrasound
Which two imaging modalities can be used to obtain a more detailed image of the heart than a normal CXR?
CT
MRI
What are the advantages of taking a chest X-ray to obtain an image of the heart?
Very quick and easy to do
Image is immediately available
What are a couple of disadvantages of using a chest X-ray to look at the heart?
Patient receives a dose of radiation
CXRs can be a bit non-specific sometimes
What is the main investigation carried out in radiology departments?
CXR
On a CXR, the outline of the heart should be ___.
sharp
What is the cardiothoracic ratio?
Maximum diameter of the heart / Maximum diameter of the thorax
A normal cardiothoracic ratio should be less than or equal to __%.
50%
The cardiothoracic ratio can only be used when working with __ chest X-rays.
PA
Why may heart size be falsely exaggerated on a CXR?
CXR is AP
Patient has not inspired fully
Patient has rotated
On a poorly taken CXR, heart size may be ___ leading to a false diagnosis of ___.
enlarged , cardiomegaly
Which imaging technique is used to assess the condition of the coronary arteries?
Angiogram
What are some disadvantages of using an angiogram to assess a patient’s coronary arteries?
Patient receives a dose of radiation Angiography is invasive There may be complications Angiography requires hospital admission Patient may be allergic to the contrast (e.g iodine)
Why may patients receiving a coronary angiogram require an admission to hospital?
Procedure is invasive
There may be vascular complications
Which contrast, used in coronary angiography, may patients be allergic to?
Iodine
What is an echocardiogram?
An ultrasound of the heart
What structures can an echocardiogram be used to assess?
Cardiac valves
Cardiac chambers
Does an echocardiogram emit any radiation?
No
What are some disadvantages of using an echocardiogram to assess the structure of a patient’s heart?
Very operator dependent - expertise required
Patient dependent - weight concerns
Doesn’t offer the whole picture
What imaging modality offers a very good, non-invasive view of the heart anatomy and coronary arteries?
Cardiac CT scan w/ IV contrast
What imaging modality is very good at capturing the stroke fraction of the heart?
CT scan
What are some disadvantages of using a cardiac CT scan to view the heart?
High radiation dose
Patient may be allergic to the contrast (e.g iodine)
Requires specialist CT equipment
What imaging modalities can be used to assess vascular stenosis / patency?
Angiography
CT scan
What is the gold standard investigation used to obtain images of the heart?
Cardiac MRI
Which imaging modality gives an excellent view of the soft tissue and anatomy of the heart?
Cardiac MRI
Which vessels cannot be seen particularly well on a cardiac MRI?
Coronary arteries
What are some disadvantages of cardiac MRI scanning?
Long imaging times (patient has to lie still for ages)
Claustrophobia
MRI contraindications ( e.g PACEMAKERS)
Need specialist equipment and expertise to interpret images
Which kind of patient may be unsuitable for a cardiac MRI scan?
Claustrophobic
Those with metal implants (mechanical stents, pacemakers particularly)
Those who cannot lie still for extended periods of time
Do MRI scanners emit any radiation?
No
Which imaging method can be used to determine the impact of coronary artery disease on muscle perfusion?
Nuclear cardiology
In nuclear cardiology, patients undergo stress testing with a vasodilator such as ___ and are then given a radioisotope to obtain data about myocardial perfusion.
Adenosine
Dihydropyridine
