Imaging The Cardiovascular System Flashcards
X rays advantages vs disadvantages
Advantages:
Easy to carry out and immediately available with answers
Disadvantages:
Radiation and can be non-specific and might not give the answer
What is the cardiothoracic ratio? (CTR)
Ratio of the maximum diameter of the heart divided by the maximum diameter of the thorax
A normal CTR should be less than or equal to 50% of (width of heart to the thorax)
When would the CTR be exaggerated in size?
Taken with AP projection
Poorly inspired
Rotated
Be careful not to misdiagnose
Angiography advantages and disadvantages?
Advantages:
Excellent coronary arterial imaging
Assess anomalies
Assess coronary plaques/stenosis
Assess stents/CABGs
Disadvantages:
Radiation
Invasive - require of an arterial puncture
Complications
May need admission for at least 24hrs
Contrast allergy and nephropathy (can also cause renal impairment)
Echocardiography advantages and disadvantages? (Ultrasound of heart)
Advantages:
Immediately available
Functional assessment of the heart
Easiest assessment to look at valves
Chamber assessment
No radiation so can repeat
Disadvantages:
Operator dependent - must have expertise
Patient dependent - may be obese or underlying chest deformity
This can result in an Incomplete cardiac assessment
Cardiac CT scan following IV contrast advantages and disadvantages?
Advantages:
Excellent cardiac anatomy imaging
Non-invasive coronar artery assessment
Functional assessment - look at end systolic and diastolic volume and ejection fraction
Chamber assessment - very clear
Able to look at vessels leaving heart and lungs
Disadvantages:
Heavy radiation dose
Resolution still not as sharp as catheter angiography
Potential contrast allergy/nephropathy
Need for special CT equipment/expertise
What do we use IV contrast in cardiac CT?
Need contrast to look at vascular lumen to see if there’s any stenosis
Cardiac MRI advantages and disadvantages?
Advantages:
No radiation, so no issue it’s repeat exams
Excellent soft tissue resolution - better than CT
Anatomical assessment excellent
Functional assessment excellent
Disadvantages:
Long imaging times
Claustrophobia
MRI contraindications - patient may have pacemaker
Need special MRI equipment and expertise
Not very useful for coronary arteries at present
Most dont require an injection citrate but some might require Gadolinium contrast
What are the cardiac MRI applications?
Can specifically look at right ventricular outflow tract in patients suspected of having right heart disease
Cardiac function can be calculated by cardiac MRI (left ventricular muscle mass and ejection fraction)
What are the different cine cardiac MRI views?
A cine view/examination uses the classic 4 chamber projection and provides a dynamic visual assessment of cardiac function, similar to echocardiography
A cine cardiac MRI series using the 2 chamber projection at the left to look at anterior and inferior wall to see how good it contracts
A cine cardiac MRI series using the short axis projection to see true cross section of the left ventricle separated by ventricular septum, left ventricle shows anterior, inferior and septal and lateral walls and can be assessed on wall thickening or thinning and the function
What is nuclear cardiology?
Used to assess the left ventricular myocardial perfusion, where most cardiac muscle is located usually performed in patients with breathlessness and chest pain to look at perfusion of underlying myocardium
Often used to determine the impact of coronary artery disease on regional myocardial perfusion, this influences o whether patients receive medical or surgical treatment for their atrial disease
It displays images of the heart in three standard projections
How do you carry out nuclear cardiology?
Patients undergo a stress procedure; normally given adenosine or dipyridamole which is a vasodilator and given radioisotope to look at the tracer uptake within the myocardium
What to do before analysing a CXR?
Check patients name and DOB
Are you looking at the CXR the correct way round?
Is it technically adequate? (Consider the “ations”)
- inspir-ation
- rot-ation
- penertr-ation (is there enough radi-ation?)
