Uncommon pathology of the Carotid System Flashcards
What pathology is known as the abnormal growth and development of the muscular layer of an artery wall with fibrosis and collagen deposition causing a localized series of stenoses?
Fibromuscular dysplasia
What are the other names for a carotid body tumour?
- Paraganglioma
- Chemodectoma
Where are carotid artery tumours located?
At the carotid bifurcation
What vessel is most commonly affected by tortuosity?
ICA
In the case of a tortuous vessel, where should you document doppler velocities?
Before, in, and beyond the curve/kink
What type of waveform may be seen if a tortuous vessel is producing a stenosis?
Tardus parvus in the case of a distal stenosis
What pathology is known as a separation of layers of an artery by a tear in the intima?
Arterial dissection
In what 3 clinical situation are dissections seen?
- Extension into the CCA from aortic dissection
- Trauma to the ICA
- From underlying disease such as FMD, arteritis, or defects in the vessel wall collagen
What is the hallmark appearance of an ICA dissection?
- Intramural hematoma
- Luminal narrowing or occlusion of true lumen
In a dissection, if blood exits the false lumen via a secondary tear PROXIMAL to the original tear, will flow appear antegrade or retrograde?
Retrograde
In a dissection, if blood exits the false lumen via a secondary tear DISTAL to the original tear, will flow appear antegrade or retrograde?
Antegrade
What is the MOST COMMON cause of stroke in young and middle aged individuals?
Dissection
Patient symptoms with an ICA dissection vs CCA dissection?
- ICA:
- Unilateral pain of head, neck, and face
- Partial Horner syndrome (ptosis: drooping of eyelid), miosis: constriction of the pupil)
- Cerebral or retinal ischemia - CCA: headaches and neck pain
In a dissection, where is the true lumen in relation to the false lumen?
True lumen is anterior to the false lumen
Where in the ICA are most cases of dissection?
Very superior and not identifiable on a carotid scan
What pathology contains abnormal growth of smooth muscle cells and fibrous tissue?
FMD
What is the most common sonographic presentation of FMD?
“String of beads” and dilation
What arteries are typically affected by FMD?
ICA and renal arteries
In what population does FMD usually occur?
Young females
What is the most common symptom of renal FMD?
Hypertension
What is the most common symptom of cerebrovascular FMD?
Headaches
When a patient presents with symptoms of FMD, what artery is very crucial to try and image?
Distal ICA
Where are carotid body tumour located?
Adventitia of the carotid bifurcation
What type of cells do carotid body tumours (paraganglioma) arise from?
Chemoreceptor cells
What does the carotid body control?
Blood pressure and pH
SF of carotid body tumour?
- Hypoechoic mass between the ICA and ECA
- Highly vascular and are fed by branches off ECA
- Low-resistance waveform
What arterial layers are affected in a carotid aneurysm?
All three layers
Where are carotid aneurysms mostly found?
CCA and ICA bifurcation and are FUSIFORM
What is the main cause for a carotid aneurysm to occur?
Atherosclerosis
Patient presentation with a carotid aneurysm?
Non-tender, pulsatile mass
What is the difference between a true aneurysm and a pseudoaneurysm?
True aneurysm - involves all three wall layers
Pseudoaneurysm - only involves intimal layer
What usually causes a pseudoaneurysm?
Trauma
What should be documented with a pseudoaneurysm?
- The PA itself
- The neck of the PA
- The feeding artery
- Measure outer size of the PA to include any thrombosed component
- Measure the width and length of the neck
What kind of doppler flow pattern is seen with a pseudoaneurysm?
To and Fro flow in the neck of the PA
What type of colour sign is seen in a pseudoaneurysm mass?
yin-yang sign
What does RIAI stand for?
Radiation-Induced Arterial Injury
What can be caused at the site of treatment with RIAI? What artery will this occur?
Atherosclerosis in the CCA which can cause stenosis
The maximum area of stenosis in radiation-induced lesions tends to be located where?
Distal end of the stenotic area
Are radiation induced or NON-radiation induced stenotic lesions longer?
Radiation induced - significantly longer
What pathology is the inflammation of the artery wall?
Arteritis - may produce thickening, stenosis, and occlusion
What are the two types of arteritis? What population are they most common?
- Takayasu’s - affect aortic arch in a specific order: Subclavian –> CCA –> Aorta –> renal arteries
(most common in younger women) - Giant cell arteritis - affects medium and large vessels - aortic arch, axillary, carotid
(most common in elderly people)
SF of takayasu’s arteritis?
Long, smooth, homogenous thickening of arterial walls
What additional arteries are scanned with giant cell arteritis? (hint: higher in the head)
Common superficial temporal artery and it’s branches: Parietal and frontal branches
What sonographic sign is seen with takayasu’s arteritis?
Macaroni sign in TRV - concentric and evenly distributed around vessel
What is a common sonographic feature in the temporal artery that is indicative of temporal arteritis?
Echolucent halo around temporal artery
What vessel layer do carotid body tumours arise in?
Adventitia
What is the main cause of a carotid aneurysm?
Atherosclerosis
For a scan ordered for giant cell arteritis, what artery MUST be looked at?
Superficial temporal artery (STA)
When examining Takayasu’s arteritis, what vessel must you pay extra attention to?
Proximal CCA
When examining Giant cell arteritis, what vessel should you make sure to assess?
Superficial temporal
