More and more people are coming forward for carotid ultrasound screening at their medical appointments. This is a reflection of the importance people place on their health, which is a good thing from this perspective. This article teaches you how to understand the significance of carotid ultrasound, and hopefully helps you to have better health care.
1.Which carotid vessels can be examined by carotid ultrasound? What diseases can be detected?
Ultrasound can examine multiple vessels in the neck, including the carotid system and vertebral arteries.
The term “carotid ultrasound” usually refers to the carotid artery system. The carotid system is divided into the common carotid artery, the internal carotid artery and the external carotid artery depending on the location.
Cervical vascular ultrasound can simultaneously examine the vertebral arteries, which are divided into left and right sides and supply the posterior 1/3 of the cerebral hemispheres, the brainstem, and the cerebellum. Since the vertebral artery originates from the subclavian artery (in most cases), the two are closely related and the subclavian artery is sometimes examined as well.
The most common diseases that can be examined with cervical vascular ultrasound are: atherosclerosis of the cervical vessels, including plaque formation and, in severe cases, stenosis or even occlusion of the vessels as a result. Next, it can also examine: certain types of vasculitis (e.g., aortitis), vascular entrapment (e.g., carotid artery entrapment, vertebral artery entrapment), carotid vascular stenosis after radiation therapy, fibromuscular dysplasia, aneurysm, and jugular vein disease.
2. How to read the carotid ultrasound report?
The report will generally describe the intima-media thickness (IMT) of the carotid artery, and generally exceeds 0.10 cm to diagnose intima-media thickening.
It also describes the presence of atherosclerotic plaques (hereinafter referred to as “plaques”) in the vessel wall, the location, number, size, morphology and echogenic characteristics of the plaques, and the size of the plaques is often expressed as “length cm X thickness cm”. If the plaque is severe enough to cause stenosis, the report will describe the site and degree of stenosis, and the degree of stenosis is usually expressed as a percentage (%).
There are other more specialized parameters such as vessel diameter, blood flow velocity, and other hemodynamic parameters that are difficult to read on your own without a medical background.
3. What is intima-media thickening? What is atherosclerotic plaque? What is vascular stenosis? What is the relationship between intima-media thickening, plaque and stenosis?
The intima-media thickness (IMT) refers to the thickness of the intima and intima of the vessel wall, and increases with age. On average, the IMT increases by 0.01 cm for every 10 years of age, and an IMT thickening of more than 0.10 cm is diagnosed.
Atherosclerosis is a complex process, simply put, it is the deposition of lipids in the vessel wall causing plaque, and it is also a pathological aging process of the vessel wall. To use an analogy, it is like the rusting and thickening of the inner wall of a water pipe.
Various causes can lead to narrowing of the lumen of the blood vessels, the most common cause being atherosclerosis. To use an analogy, it is like a water pipe wall rusting and thickening, and the inner diameter of the water pipe can become thin and narrow.
The relationship between the three: Intima-media thickening is often an early manifestation of atherosclerosis, and thickening to a certain degree is atherosclerotic plaque (but intima-media thickening is not always an early manifestation of atherosclerosis and does not necessarily develop into plaque. Intima-media thickening is also seen in hypertensive disease, old age, etc.). Plaques that are severe enough, or plaque rupture secondary to thrombosis, can lead to narrowing of the vessel lumen. A relatively small plaque will not lead to stenosis and the stenosis rate does not need to be calculated at this point.
4. What does 70% stenosis mean? Why is it necessary to calculate the stenosis rate? How is it calculated?
Simply put, 70% stenosis means “70% blocked, 30% open”.
There are many ways to calculate the stenosis rate, such as the diameter method (comparing the residual diameter with the original diameter) and the area method (comparing the residual lumen area with the original lumen area in cross-section). Although the pipe diameter method and area method are intuitive and easy to understand, they also have their own limitations. The currently accepted international standard for determining the degree of stenosis by ultrasound – combining various parameters to make a stenosis determination – is more often used, classifying the degree of stenosis as <50%, 50%-69%, 70%-99%, and 100% (complete occlusion).
The main purpose of calculating the stenosis rate is to guide the next step in treatment and selection of a treatment plan. For example, asymptomatic carotid artery stenosis of 70% or more requires consideration of surgery or interventional stenting; symptomatic carotid artery stenosis of 50% or more requires consideration of surgery or interventional stenting; occlusions generally cannot be treated with further surgery or stenting, with a few exceptions; and regardless of surgery or interventional stenting, medical medication is generally required at the same time.
5. Why are the stenosis rates reported by ultrasound and other tests not completely consistent?
Ultrasound, CT angiography (CTA), magnetic resonance angiography (MRA), and digital silhouette cerebral angiography (DSA) are commonly used for cerebrovascular examinations, and the final reported stenosis rates will not be exactly the same due to the different principles of these examinations and different methods of calculating stenosis rates. Different examination methods and calculation methods have their own advantages and shortcomings, and there is a certain conversion pattern between them, and clinicians will make a comprehensive judgment based on different imaging performances.
6. Does a normal carotid ultrasound mean that I will not have a stroke?
A normal carotid ultrasound only means that the blood vessels in the neck are normal, but there are other parts of the body that are not detected, such as the coronary arteries of the heart and the blood vessels of the brain other than the neck. Those parts of the body that are not detected may not be completely normal, but may have some or all problems. Also, there are many causes of stroke, and atherosclerosis is only one of the common causes. Therefore, there is no 100% correspondence between a normal carotid ultrasound and the occurrence of stroke.
7. Can carotid plaque dislodge and cause a stroke?
Many people ask this question and are overly anxious about it, but in fact the majority of small carotid plaques are unlikely to dislodge. The more severe plaques are at risk for rupture, secondary thrombosis, and stroke due to dislodgment of the thrombus.
8. How is carotid atherosclerotic plaque treated medically?
(1) For lifestyle risk factors: diet control, proper exercise, smoking cessation, alcohol restriction, weight loss in overweight or obese people.
(2) Target disease risk factors: blood pressure, blood sugar, blood lipids, hyperhomocysteinemia, etc. In hypercholesterolemia mainly statin lipid-lowering drugs.
(3) A cardiovascular risk assessment should be performed, and patients with relatively high risk should take antiplatelet drugs, the most commonly used being enteric aspirin.
The choice of which drug to take will also take into account the patient’s other underlying diseases, and age is also important.
9. Can plaque treatment subside?
According to studies, some patients with plaques can shrink (also called “reversal”) after long-term strict control of risk factors and follow-up with ultrasound monitoring. However, this is very difficult and complete regression is unlikely. The goal of treatment is generally to achieve – no or slow progression with age.
10. What are the clinical implications of carotid ultrasound?
Atherosclerosis is a disease of the systemic vasculature, and carotid ultrasound is only a window that reflects to some extent the degree of atherosclerosis. The purpose of our screening vascular ultrasound is to target people at high risk for stroke, to detect stenosis, and to select further more aggressive treatment. For example, those found to have severe carotid stenosis are treated with carotid endarterectomy or stenting to prevent the possibility of a more serious stroke. However, severe stenosis is a very small percentage of the population, and in most cases atherosclerotic plaques are found, reminding us to intervene in those unhealthy lifestyles and treat the corresponding disease risk factors.
We can use the disease chain to compare the onset of stroke: lifestyle risk factors (smoking, obesity, alcoholism, sedentary lack of exercise, unbalanced diet, etc.) → disease risk factors (hypertension, hyperglycemia, hyperlipidemia, etc.) → vascular hardening, plaque, stenosis → cardiovascular disease (stroke, coronary heart disease). The top doctor treats the untreated disease, regardless of whether there is stenosis or plaque, attention should be paid to control risk factors, including lifestyle risk factors and disease risk factors. It is totally unnecessary to be anxious and overly anxious when plaque is found on carotid ultrasound; and it is wrong to continue unhealthy lifestyle (such as continue smoking and not exercising) if carotid ultrasound is not a problem.