cardiovascular system Flashcards
structure of veins and arteries
they have similar structure except for a few notable differences; arteries have a thicker muscular middle layer and vein have valves that ensure blood only travels in 1 direction.
vessel layers
external to internal
tunica externa -> tunica media -> tunica intima
ultrasound
very useful in investigating causes heart failure, valve disorders and cardiomyopathy. performed using either transthoracic or a transoesophageal approach. can also provide functional information such as blood flow dynamic and ejection fraction, but not as useful for visualising coronary arteries
fluoroscopy
similar to X-ray is poor at visualising the heart, however with the introduction of contrast is a valuable guidance tool for procedures. alongside CT is the modality for imaging coronary arteries, with the added ability to guide treatments such as coronary stenting, pacemaker insertion and electrophysiology studies
MRI
mostly used in the chronic / follow up setting, however it ha advantages over that include the ability to provide functional information, e.g. myocardial viability scanning, ejection fraction and blood flow analysis
RNI
helpful in determining functional information and significance. main investigations include SPECT, myocardial perfusion, cardiac stress test and ventriculography
neck and head arteries
- basilar artery
- circle of willis
- external and internal carotid arteries
- common carotid arteries
subclavian arteries - innominate artery
- aorta
what route does contrast take when we inject it into the right antecubital vein?
antecubital vein
basilic vein
axillary vein
subclavian vein
brachiocephalic vein
cephalic vein
superior vena cava
right atrium
lower limbs
external iliac
deep formaral
common iliac
internal iliac
gluteal
lateral sacral
internal pudendal
obturator
femoral
femoral circumflex
femoral
great saphenous
popliteal
small saphenous
anterior tibial
posterior
fibular
dorsal venous arch
digital
ultrasound
Excellent at vascular imaging due to superior contrast resolution, and the ability to obtain functional information by using doppler, colour flow and analyse arterial waveforms. recommended for use to guide needle insertion for vascular interventions. as always limited by body habitus, overlying bone/gas and unable to
visualise a large area compared to CT/MR
CT
widely used for: aortic aneurysms, aortic dissection, bleeds anywhere in the arterial / venous system, liver portal system assessment, where invasive angiography is deemed unsuitable / high risk
CT benefits
- non invasive compared to direct angiography / venography
- lower risk of causing embolism / rupture / vascular injury
- whole body / large area acquisition
- better natural contrast resolution than fluoroscopy
- ability to render 3D images for superimposed vessels
CT limitations
- mostly unable to treat
- usually a high dose than fluoroscopy but this does depend on procedure
- poorer contrast resolution to MR
- inferior spatial resolution to fluoroscopy for smaller vessels
MRI
used less frequently, particularly in trauma scanning but has similar applications to CT
fluoroscopy
in most situations the superior modality for vascular imaging,
particularly when intervention is anticipated. fluoro benefits from being real time, adjustable and repeatable. it has very high spatial resolution (inferior only to X-ray). also has very high temporal resolution (needed for real time analysis)
atrial / ventricular septal defect
most common in unborn babies, congenital heart defect where the blood flows between the atria / ventricles of the heart. caused by a patent foramen ovale. this results in the oxygenated blood of the left side of the heart mixing with the poorly oxygenated blood of the right heart, or vice versa. which leads to lower than usually oxygen levels in arterial blood. some defects repair themself. treated using a septal occlusion device, places percutaneously / surgically. diagnosed using in utero ultrasound for neonates. chest XR to assess device position, flour to guide insertion
hypertrophic cardiomyopathy
heart muscle becomes abnormally thickened, making the muscle stiff and inefficient. usually, affects the left ventricle, but can affect any chambers / septa of the heart
dilated cardiomyopathy
heart muscle becomes stretched and thinner, resulting in a weak inefficient heart. can be congenital or acquired. symptoms are SOB, lower limb lymphoedema, tiredness. usually affects left ventricle. treated with medication / transplant
coronary artery disease
narrowing / blockage of the coronary arteries, can be acute / chronic. often leads to myocardial infarction if untreated. patients often present with severe chest pain and ECG changes. treatment is mostly either percutaneous coronary intervention or bypass surgery. XR to rule out other causes, CTCA to assess vessels and IR for stent placement
How CT Coronary Angiogram is performed
plain scan of the heart to receive a calcium score. if this is high there is no need to proceed. if it doesn’t indicate the calcium is flow limited carry on. external ECG is placed onto the patient which is read by the scanner in order to scan between the heart beats to reduce motion artifacts. then bolus tracking or a test bolus is set up to ensure the scan is performed at the optimal time for contract enhancement of the coronary arteries,. usually ROI is placed in the ascending aorta, triggers at 150HU
carditis (infection)
infection of the tissues surround the heart.
pericarditis is usually due to a viral infection. diagnosis based on chest pain, ECG, imaging with U/S. treated with NSAIDS.
myocarditis is usually due to viral infection, or TB and autoimmune disorders. treatment with steroids / diuretics / no exercise.
endocarditis is inflammation of the inner most later, and usually involves the cardiac valves. usually caused by a bacterial infection. OPG imaging pre heart surgery. treated with IV ABX, very common in recreational IV drug users. often diagnosed with tranoesophageal echo, vegetative mass seen on valves or heart muscle wall
congestive heart failure
cardiac function is impaired, resulting in reduced rate of blood flow through the body, whilst pressure in the heart increases. the chambers of the heart may respond to the increased pressures by stretching to increase the volume of blood they can hold or by becoming stiff and thickened. as a result of the fluid imbalance, the kidneys respond to retain fluid and salts. this can occur in the lower limbs, lungs or other organs. as the body becomes congested with extra fluid
diastolic dysfunction
the heart contracts normally but the ventricles don’t relax properly, or are stiff = less oxygenated blood pumped around the body
systolic dysfunction
when the heart doesn’t contract with enough force = less oxygenated blood pumped round the body
aortic valve stenosis
most common valvulopathy. describes a narrowing of the opening of the aortic valve and the left ventricle. results in the left ventricle working harder, and an increase in pressure from the left ventricle into the aorta. this extra pressure on the left ventricle is what can cause signs on heart failure. varying appearances due to stage and severity of disease. chest XR can be normal or show evidence of cardiomegaly. dilated ascending aorta due to increased pressure, normal descending aorta, normal heart size. valvular calcification with signs of heart failure such as cardiomegaly and oedema may be seen in the later stages.
aortic dissection
tear in the intimate wall of the artery. blood can flow between the laters of the blood vessel wall. usually originate in the ascending aorta or the aortic arch. XR may be normal, can demonstrate a widened mediastinum. CT highly specific and sensitive, using contrast can provide information for classification and surgical planning. US in the the form of TOE is highly sensitive and specific but is invasive and has limited access. treated with stent / replacement of aorta
aortic aneurysm
blue or dilation of the vessel walls. aneurysmal wall is weaker than normal meaning there is greater risk of rupture. US used to screen and Monte. CT angio is helpful in planning EVAR. XR for following
dual / left superior vena cava
occurs when cardinal vein does not obliterate during feral development. left SVC usually connect to the coronary sinus, but can connect to the left atrium causing a shunt
transposition of great arteries
potentially fatal switch of aorta / pulmonary artery. usually detected during prenatal US scans. fixed with arterial switch surgery
arteriovenous malformation
tangle of blood vessels. can occur anywhere in the body. can be surgically removed but often embossed with glues / coils that are visible on XR
pulmonary embolism
blockage in the pulmonary artery. SOB, chest pain, low ox are all symptoms. diagnosis is D-dimer blood test, CTPA and VQ RNI test
CTPA = test bolus - small amount of contrast
injected, area of interest set and time
taken to reach peak enhancement
determined. this delay is then used to
conduct the scan
bolus tracking -region of interest is
determined (usually the pulmonary
trunk), contrast injected and when
threshold HU met, scan is triggered to
start
SVC / venous obstruction
when the vena ave is blocked by either clotting or stenosis. body attempts to circumvent the obstruction by forming collateral vessels. very common in patents receiving haemdialysis. also common in patents with repeated central line insertions / vascular interventions
deep vein thrombosis
blood cloth that forms in a vein. can break off and cause pulmonary embolism, diagnosed with US. vein is no longer compressible. use Well’s criteria
