# Carotid Artery Plaque on Ultrasound: A Patient's Guide to the 2020 ASE Guidelines for Measuring Atherosclerosis and Heart Risk This 2020 guideline from the American Society of Echocardiography (ASE) explains how ultrasound of the carotid (neck) arteries can detect and measure plaque — the fatty buildup inside artery walls — to estimate a person's risk of heart attack, stroke, and other cardiovascular events. The authors define two types of plaque, recommend specific measurement methods, and review research showing that plaque measurements predict risk better than older approaches such as measuring artery wall thickness alone. Because carotid plaque reflects the total burden of atherosclerosis throughout the body, including the coronary arteries, a standardized ultrasound assessment can reclassify risk in people who might otherwise appear low-risk. For patients, the key message is that finding and quantifying carotid plaque adds important information beyond traditional risk factors like cholesterol and blood pressure. # Carotid Artery Plaque on Ultrasound: A Patient's Guide to the 2020 ASE Guidelines for Measuring Atherosclerosis and Heart Risk ## Table of Contents - Key Points - Why the Carotid Artery Is a "Window" Into Heart Risk - Why This Guideline Was Written - What These Guidelines Cover - Two Types of Plaque: Protuberant and Diffuse - When Is Carotid Plaque "Clinically Significant"? - The New Plaque Grading System - Measuring Plaque with the "Plaque Score" - Measuring Maximum Plaque Height (Thickness) - What Plaque Height Means for Health Outcomes - Measuring Plaque Area - The Panel's Six Key Recommendations - Limitations and Caveats - What This Means for You - Frequently Asked Questions - Source Information ## Key Points - Carotid ultrasound can detect plaque, offering a window into atherosclerosis throughout the body. - Plaque measurement predicts cardiovascular risk better than measuring only artery wall thickness (CIMT). - Plaque is defined as a focal bulge into the artery lumen or diffuse wall thickness of 1.5 mm or greater. - A plaque score and maximum plaque height are standardized methods to quantify plaque burden for risk. - Routine repeat CIMT testing is not recommended without symptoms unless diffuse plaque (1.5 mm) is present. ## Why the Carotid Artery Is a "Window" Into Heart Risk Atherosclerotic cardiovascular disease — a group of conditions caused by the buildup of plaque inside artery walls — remains the leading cause of illness and death worldwide. Atherosclerosis (hardening and narrowing of the arteries) can develop silently for years before it causes problems. Finding it early offers a chance to act. The carotid arteries, located on each side of the neck, supply blood to the brain. They lie close to the skin, which makes them easy to image with ultrasound. According to the guideline authors, ultrasound of the carotid artery provides a unique "window" into a patient's underlying cardiovascular risk. The presence and degree of atherosclerosis, defined by plaque detected in the carotid arterial system, has been used to estimate, classify, or reclassify an individual's cardiovascular risk. Beyond overall risk prediction, carotid atherosclerosis is also a known predictor of other cardiovascular events, such as stroke caused by narrowing of the vessel (luminal stenosis) or by plaque rupture. In short: what happens in the neck arteries often reflects what is happening in arteries throughout the body. ## Why This Guideline Was Written Doctors have used two distinct ultrasound approaches to estimate cardiovascular risk. The older approach measures the carotid intima-media thickness (CIMT), which is the thickness of the two innermost layers of the artery wall. The newer approach assesses carotid arterial plaque itself. CIMT measurement identifies areas of increased carotid artery wall thickness. It provides an easily accessible imaging biomarker for classifying cardiovascular risk in individuals and in population studies. However, questions about the precision of CIMT measurements remain. There is now recognition that assessing carotid arterial plaque offers an even greater risk stratification benefit than CIMT. This has led to a paradigm shift — a change in the standard way of thinking — in which ultrasound parameters are used for risk prediction. The greater benefit is seen with plaque assessment compared with CIMT. Why the difference? It is now recognized that CIMT may represent more than one distinct disease process, while plaque primarily reflects atherosclerosis itself. CIMT may predominantly reflect the presence of cardiovascular risk factors, such as high blood pressure (hypertension). Carotid plaque, in contrast, is a sub-intimal process (developing beneath the innermost artery lining) that correlates with the overall burden of atherosclerosis in the coronary vascular bed — the arteries that supply the heart muscle. One striking finding drives this guideline: the high prevalence of carotid atherosclerosis in people who have an otherwise low Framingham risk score. The Framingham risk score is a traditional tool that estimates a person's 10-year risk of heart disease using factors such as age, cholesterol, blood pressure, and smoking. When plaque is present despite a low score, this has potential implications for screening of subclinical atherosclerosis — disease that has not yet caused symptoms. Technology has also advanced dramatically. Since the previous ASE consensus statement was published in 2008, dedicated three-dimensional (3D) vascular ultrasound probes became widely available, and more recently a 3D matrix array probe for carotid ultrasound was released with analysis software. This document is the first to provide systematic recommendations for standardizing the quantification of carotid arterial plaque for cardiovascular risk stratification. ## What These Guidelines Cover This consensus statement provides recommendations for two-dimensional (2D) and three-dimensional (3D) quantification of carotid arterial plaque by ultrasound for the purpose of cardiovascular risk stratification. The document also discusses emerging techniques, including the role of ultrasound enhancing agents (UEA) — sometimes called "contrast agents" — for assessing intra-plaque neovascularization (the growth of tiny, fragile new blood vessels inside plaque) and plaque composition analysis. ## Two Types of Plaque: Protuberant and Diffuse Carotid atherosclerosis is thought to develop beneath the intimal layer (the innermost lining of the artery) in the sub-intima. In contrast, the medial layer (the middle muscle layer) is subject to non-atherosclerotic medial hypertrophy — a thickening of the muscle layer commonly caused by aging and hypertension. This distinction matters more than you might think. Because the largest portion of the CIMT measurement consists of the medial layer — about 99% in healthy individuals and about 80% when disease is present — CIMT has not been shown to consistently add to cardiovascular risk prediction. Carotid plaque, on the other hand, represents the atherosclerotic process itself. It starts in the intimal layer, and it has been shown to predict cardiovascular events better than CIMT. Despite this difference, it can be difficult to tell medial thickening apart from diffuse atherosclerotic plaque on an ultrasound image. Some plaques are discrete (distinct) lesions that are easy to distinguish from the surrounding wall. But plaque can also be eccentric (off-center) and spread over the surface of the wall, appearing indistinct from the media. In such cases, it is hard to know whether the image shows simple medial thickening or eccentric, diffuse plaque. Because of this difficulty, arbitrary definitions have been proposed. A commonly reported threshold value to define diffuse plaque is a CIMT greater than 1.5 mm, or a focal intimal-medial thickening greater than 50% of the surrounding area. Confusion occurs because ultrasound resolution now allows visualization of distinct protuberant plaque lesions that can be smaller than this threshold value. In fact, the definition of plaque has varied widely from study to study: - In one study, plaque was defined as a focal thickening of the intima-media greater than 1 mm, protruding into the lumen, and at least twice as thick as the surrounding normal CIMT. Depending on how it was applied, this produced plaque definitions ranging from 0.5 mm to greater than 1.5 mm. - Another study defined plaque simply as a CIMT greater than 1.2 mm. - The European Mannheim consensus defined plaque as a focal thickening that encroaches into the lumen by 0.5 mm or by 50% of the surrounding intimal-medial thickness, or where CIMT is greater than 1.5 mm. The ASE writing panel chose a threshold that is slightly more conservative than the Mannheim consensus. They recommend using 1.5 mm or greater (rather than greater than 1.5 mm) as the cutoff CIMT value for the presence of diffuse plaque. A newly established Plaque Grading Consensus, described below, now allows identification and characterization of protuberant plaque lesions smaller than the CIMT threshold used for diffuse plaque. Modern ultrasound technology can visualize such small lesions in exquisite detail, allowing both quantification and even potential analysis of plaque composition. **Recommendation #1:** Carotid arterial plaque seen on ultrasound (with or without an ultrasound enhancing agent) should be defined one of two ways: 1) any focal thickening thought to be atherosclerotic in origin that encroaches into the lumen of any segment of the carotid artery (protuberant-type plaque), or 2) in the case of diffuse vessel wall atherosclerosis, when CIMT measures 1.5 mm or greater in any segment of the carotid artery (diffuse-type plaque). **Recommendation #2:** Both protuberant and diffuse types of carotid arterial plaque should be evaluated for cardiovascular risk stratification and for the serial (repeat) assessment of atherosclerosis. ## When Is Carotid Plaque "Clinically Significant"? Some centers consider repeat evaluation of CIMT when the value is above the 75th percentile for a person's age, race, and gender. However, there is little evidence about how often repeat testing should be done. An interval of 2 to 5 years has been used in population studies, although published evidence suggests that more frequent CIMT measurements could increase the precision of tracking CIMT progression over time. The expert panel weighed this evidence and came to a clear conclusion: they recommend **against** serial CIMT measurements for cardiovascular risk stratification, especially when the measurement does not meet the threshold for diffuse plaque (1.5 mm or greater). They note that, based on limited or anecdotal evidence, serial CIMT may still have value in the hands of some experts for research purposes, for monitoring progression or regression (shrinkage) of disease in specific cases, and as a potential tool to help change patient behavior. The panel also acknowledges that an individual patient's CIMT can increase to 1.5 mm or greater over time, which would signal the development of diffuse atherosclerotic plaque by their definition. However, the clinical usefulness of such long-term CIMT monitoring is not yet established. One important age-related recommendation stands out: the panel suggests that a CIMT of 1.5 mm or greater be considered a clinically significant lesion for patients younger than 65 years of age. ## The New Plaque Grading System The thickness (also known as "height" in the long-axis ultrasound view) of a carotid plaque lesion was chosen as the initial measure to define plaque. This choice was made because thickness measurement is widely available and can be applied to both protuberant and diffuse types of plaque lesions. Additional quantification techniques, such as area and volume, apply mostly to protuberant-type plaque. They are difficult to use in atherosclerotic lesions that are diffusely layered along the intimal wall. Such diffuse lesions may also contain focal or widespread wall calcification (calcium deposits) arranged in a concentric or eccentric pattern. Calcification can represent either atherosclerotic or non-atherosclerotic processes. The panel's grading system standardizes the size of an individual plaque lesion for comparison across studies. It is important to note that the grading system does **not** reflect the degree of vessel occlusion (how blocked the artery is). Here is how the grading works: - **Grade I** applies only to small protuberant-type plaque lesions. Ultrasound can now resolve such small protuberant lesions clearly. However, if plaque is non-protuberant (diffuse or eccentric) and less than 1.5 mm thick, it is currently not possible to tell whether the thickening is entirely due to medial thickening or is truly intimal plaque. - **Grade II and Grade III** apply when CIMT reaches 1.5 mm or greater. At this thickness, the framework attributes the thickening to diffuse atherosclerotic plaque (mostly intimal rather than medial), and the lesion is considered a "plaque equivalent." Grades II and III measurements are applied to obviously protuberant plaque in the same manner, for simplicity. ## Measuring Plaque with the "Plaque Score" Interest in plaque quantification grew significantly after the ARIC Study discovered that the simple presence or absence of plaque added information to risk stratification beyond what CIMT alone provided. Researchers reasoned that if simply knowing whether plaque exists can re-stratify patients beyond traditional risk factors, then measuring the amount of plaque might further personalize a patient's risk assessment. The plaque score is a semi-quantitative approach — a method that gives a rough rather than exact measure. The total number of sites containing plaque along the common carotid artery (CCA), the carotid bulb (the widened area at the branching point), and the internal carotid artery (ICA) is counted and summed. This approach varies greatly among studies: some investigators count plaque lesions in any visualized segment, while others count only lesions in easily identified segments such as the distal (far) first centimeter (cm) of the CCA, the bulb, and the proximal (near) ICA. The Rotterdam Study, a prospective, population-based study of cardiovascular disease in elderly people, used a unique process to calculate plaque score. Two key analyses from this study (with 4,217 and 6,389 participants respectively) measured the presence of carotid plaque at 6 locations in the carotid arteries: two sides each of the CCA, the bifurcation (where the artery splits), and the ICA. The total plaque score ranged from 0 to 6. It was calculated by adding the number of sites where plaque was detected, dividing by the total number of sites for which an ultrasound image was available, and multiplying by 6 (the maximum number of sites). In the second and larger of these studies (n = 6,389), patients with plaque scores of 0, 1, 2, and 3 or more points were considered to have no, mild, moderate, or severe carotid atherosclerosis, respectively. Clinical studies have shown a clear link between plaque score and future cardiovascular disease: - In the Three-City Study of 5,895 individuals aged 65 to 85 years who were free of cardiovascular disease at the start, plaque in one site was associated with a hazard ratio (HR) of 1.5 (95% confidence interval [CI] = 1.0 to 2.2). A hazard ratio compares the likelihood of an event in one group versus another — here, people with plaque compared with people without it. - The hazard ratio for plaque at 2 or more sites was 2.2 (95% CI = 1.6 to 3.1; p < 0.001 for trend). In plain terms, having plaque in multiple sites roughly doubled the risk of a cardiovascular event during follow-up. - Adding plaque information to traditional risk factors improved the area under the curve (AUC) for cardiovascular disease prediction from 0.728 to 0.745 (p = 0.04). The AUC measures how well a test discriminates between people who will and will not have an event; 0.5 is no better than chance and 1.0 is perfect. - The same addition produced a net reclassification index (NRI) of 13.7%. The NRI tells us what percentage of people were correctly moved into a higher or lower risk category based on the new information. - Another study followed 367 men (mean age 78 ± 4 years) and found that the hazard ratio for death over 4 years increased from 2.89 for a plaque score of 1 to 2, up to 4.53 for a plaque score of 7 to 12. For the purpose of risk prediction and standardization, the panel recommends that if a plaque score is calculated, counting should be limited to lesions in the distal 1 cm of the CCA, the bulb, and the proximal 1 cm of the ICA. Further standardization of the plaque score is still needed. **Advantages.** The plaque score is easy to perform and requires no advanced quantification software. Because individual plaque lesions are not precisely measured but simply visualized and counted, the angle or plane of imaging is less critical. Despite being a relatively rough reflection of plaque extent, the plaque score has more predictive value than simply reporting the presence or absence of plaque. **Disadvantages.** The plaque score is semi-quantitative and counts only the number of lesions. It does not consider additional parameters such as the size of an individual plaque lesion, which would better reflect the overall extent of atherosclerosis. In addition, because lesions are counted at distinct sites, the score may be unclear about whether two separate plaque lesions are actually connected (contiguous), which could lead to overestimation. Conversely, there may be a large amount of contiguous protuberant plaque that forms just one large lesion — in that case, the plaque score will underestimate the true extent of atherosclerosis. ## Measuring Maximum Plaque Height (Thickness) Carotid plaque thickness, or height, can be thought of as a variation of the maximal CIMT measurement. It differs in an important way: plaque height represents the degree to which the plaque protrudes outward (in a radial manner) from its origin along the vessel wall into the lumen (the open channel through which blood flows). Here is how the measurement is performed. Some investigators suggest using electrocardiographic (ECG) gating — timing the ultrasound images to the same phase of the cardiac cycle — so measurements are consistent between heartbeats. Typically, the sonographer makes cross-sectional (transverse) sweeps to check for the presence of plaque. Once a plaque lesion is identified, electronic calipers (measurement tools built into most ultrasound software) are placed beginning along the origin of the plaque at the vessel wall, extending into the lumen at right angles to the wall, along the most protuberant (outward-projecting) part of that particular plaque. The maximum plaque height or thickness among all identified plaque lesions, seen in both the right and left carotid arteries, is then reported. It is important to understand that studies using this method do not add up (sum) all plaque heights. They report the single largest plaque height measured from any plaque identified anywhere in the patient. Plaque height measured this way is highly reproducible. In the Northern Manhattan Study (NOMAS), the intra-class correlation coefficients — a statistical measure of agreement between measurements — were 0.77 for inter-observer reliability (different readers measuring the same image) and 0.94 for intra-observer reliability (the same reader measuring the same image more than once). Variability in this method relates to identifying the exact location within the vessel wall where the plaque height measurement should begin. To reduce variability across studies, the panel recommends beginning the measurement at the adventitial-medial layer (the outer connective tissue and middle muscle layers of the artery), similar to where CIMT measurement begins. ## What Plaque Height Means for Health Outcomes The maximum plaque height measured in the manner described above has been used as a key research measure because it is simple, reproducible, and captures the most severe lesion in the artery. The original guideline document reports detailed outcome data linking maximum plaque height to future cardiovascular events. The outcomes data from the original document were cut off in the text provided; however, the guideline's grading framework is built around the principle that plaque height is the foundational measure. The panel emphasizes that the measurement should begin at the same plane as the CIMT measurement so that results stay consistent with defining plaque beyond the 1.5 mm CIMT threshold. One practical point for patients: a single tall plaque may carry more significance than several small flat plaques, which is why the "maximum height" approach is used rather than averaging or summing all lesions. ## Measuring Plaque Area Carotid plaque area is described in the guideline as the most advanced of the 2D quantification methods. The technique begins with a manual sweep of the carotid artery, typically scanning the artery in cross-section, to identify plaque lesions in the first place. Once lesions are identified, the area of one or multiple plaques is measured, and the total value is reported. The original guideline document continues with detailed instructions for performing plaque area measurements, followed by sections on three-dimensional plaque volume quantification, plaque vulnerability (the tendency of a plaque to rupture and cause events), contrast-enhanced ultrasound, grayscale median analysis, and multi-modality assessment of plaque. Those sections are part of the full published guideline (see Source Information below). Plaque area shares an important limitation with other advanced measurements: it is difficult to apply to atherosclerotic lesions that are diffusely layered along the intimal wall, rather than forming discrete protuberant bumps. ## The Panel's Six Key Recommendations The guideline authors, writing on behalf of the American Society of Echocardiography, summarized their advice into six numbered recommendations. Here they are in plain language: 1. **Define plaque consistently.** Plaque seen on ultrasound should be defined as either: (a) any focal thickening thought to be atherosclerotic that encroaches into the lumen of any segment of the carotid artery (protuberant-type plaque), or (b) diffuse disease in which the CIMT measures 1.5 mm or greater in any segment of the carotid artery (diffuse-type plaque). This holds whether or not an ultrasound enhancing agent (contrast) is used. 1. **Check for both plaque types.** Both protuberant and diffuse plaque should be evaluated for cardiovascular risk stratification and for tracking atherosclerosis over time. 1. **Use a stepwise approach.** First, visually scan the carotid arterial wall for protuberant plaque. If none is found, then perform CIMT measurement to look for diffuse plaque, defined as CIMT of 1.5 mm or greater. CIMT, if performed, should be measured according to the earlier ASE Consensus Statement on the Use of Carotid Ultrasound to Identify Subclinical Vascular Disease and Evaluate Cardiovascular Risk. 1. **Do not routinely repeat CIMT.** Serial CIMT measurements are not recommended in an asymptomatic patient (someone without symptoms). Repeat measurements are only recommended if the Grade and CIMT meet the criteria for diffuse-type plaque (Grades II or III, and CIMT 1.5 mm or greater) — in which case the finding is treated as a plaque equivalent. 1. **Measure plaque height first.** Plaque thickness (height) should be measured as the initial 2D approach for quantifying carotid ultrasound plaque. Plaque height is often measured from 2D images, but it can also be obtained from a 3D image acquisition when available, to overcome the out-of-plane limitations of 2D imaging. 1. **Measure from the correct starting point.** The maximal plaque height should be measured either from the side where plaque is detected (unilateral) or from both right and left carotid segments (bilateral). A caliper is placed at the adventitial plane — the same starting plane used for CIMT measurement, to stay consistent with the 1.5 mm plaque threshold — and extended into the center of the lumen at right angles to the vessel wall. The measurement can be taken from any segment (bulb, ICA, or CCA) in the long or short axis, and the view and segment should be reported. ## Limitations and Caveats The guideline authors are careful to acknowledge what this document cannot do. The grading system standardizes the size of an individual plaque lesion, but it does not reflect the degree of vessel occlusion (how blocked the artery is). A patient could have substantial plaque burden without knowing how much it narrows the vessel. Questions about the precision of CIMT measurements remain, and the panel notes the fundamental difficulty of distinguishing medial thickening from diffuse atherosclerotic plaque. In lesions smaller than 1.5 mm that are not protuberant, current technology cannot tell whether the thickening is medial or intimal in origin. The evidence base for repeat CIMT testing is limited. The panel's recommendation against serial CIMT measurements acknowledges that published studies on testing frequency had methodological limitations. Any value of serial CIMT in research, in monitoring individual cases, or in motivating patient behavior rests on limited or anecdotal evidence. Definitions of plaque vary across research studies, which makes comparing results difficult. The panel's chosen threshold of 1.5 mm or greater is "slightly more conservative" than the Mannheim consensus, but it remains an arbitrary cutoff. The plaque score method, for all its usefulness, does not measure the size of individual lesions and can either overestimate or underestimate the true extent of atherosclerosis. Finally, the original published document was authored by experts with financial relationships to imaging and pharmaceutical companies; those relationships are disclosed in the full guideline (see below), and they are standard practice in medical guideline development. ## What This Means for You If your doctor orders a carotid ultrasound, the goal is often to look beyond your traditional risk factors. The presence of plaque — even in someone with a low Framingham risk score — can change how your doctor views your overall cardiovascular risk. Key points to discuss with your doctor: - **Plaque is more than wall thickness.** A plaque measurement may predict your risk of future cardiovascular events better than a CIMT measurement alone, because plaque directly represents atherosclerosis. - **Location matters.** Plaque in the carotid arteries reflects atherosclerotic burden elsewhere, including the coronary arteries that feed your heart. It also raises the risk of stroke from narrowing or from plaque rupture. - **One number tells the story.** Many experts now report the single largest plaque height rather than a sum of all plaque. A measurement of 1.5 mm or greater is considered clinically significant, especially for patients under 65. - **Repeating the test has limits.** Current guidelines advise against routine repeat CIMT measurements in people without symptoms, unless the first scan shows diffuse-type plaque at Grade II or III (CIMT of 1.5 mm or greater). - **Ultrasound is only one piece of the puzzle.** Plaque detection is a risk stratification tool. It works alongside blood pressure, cholesterol, blood sugar, smoking history, and family history to guide decisions about prevention — including whether to start or intensify medications such as statins. The ultimate message is encouraging: atherosclerosis can be detected early, measured accurately, and tracked over time with a safe, painless, radiation-free ultrasound test. When plaque is found, there are proven ways to slow its progression and reduce the risk of heart attack and stroke. ## Frequently Asked Questions ### What is carotid artery plaque and why does it matter for heart attack or stroke risk? Carotid artery plaque is fatty buildup inside the artery wall in your neck. Ultrasound can detect it. Because plaque in the neck reflects atherosclerosis throughout your body, including heart arteries, finding it helps estimate your risk of future heart attack or stroke, beyond traditional risk factors like cholesterol and blood pressure. ### What is the difference between intima-media thickness (CIMT) and carotid plaque measurement? CIMT measures the thickness of the two innermost artery wall layers. Plaque measurement looks for actual atherosclerotic buildup. Plaque directly represents atherosclerosis and predicts cardiovascular events better than CIMT alone. CIMT may reflect other processes, like high blood pressure. Doctors now focus more on detecting and measuring plaque. ### How is carotid artery plaque defined on an ultrasound? Plaque is defined in two ways: any focal thickening that bulges into the artery lumen (protuberant plaque), or diffuse disease where the artery wall inner-layer thickness is 1.5 mm or greater in any segment (diffuse plaque). Both types are evaluated for cardiovascular risk and tracking over time. ### What is a carotid plaque score and what does it mean for my risk? A plaque score counts how many sites in your carotid arteries have plaque. In studies, a higher score was linked to higher risk. For example, in one large study, having plaque in multiple sites roughly doubled the risk of a cardiovascular event during follow-up. The score is a semi-quantitative tool, easy to perform. ### What does a carotid plaque height measurement of 1.5 mm mean? A thickness of 1.5 mm or greater is considered clinically significant diffuse plaque, especially if you are younger than 65. Plaque height is measured from the vessel wall into the lumen at the thickest part. This single largest plaque measurement is used to assess cardiovascular risk. ### Should I have repeat carotid ultrasound tests over time? Current guidelines recommend against routine repeat CIMT measurements in people without symptoms. Repeat testing may be considered only if the first scan shows diffuse-type plaque at Grade II or III, meaning CIMT is 1.5 mm or greater. Talk with your doctor about your specific situation. ### What happens after my doctor finds carotid plaque on an ultrasound? Finding plaque is a risk stratification tool, not a diagnosis of imminent events. It guides prevention decisions, such as whether to start or intensify medications like statins. Plaque can be detected early, measured accurately, and tracked over time with ultrasound, and there are proven ways to slow its progression. ### Should I get a second opinion on my carotid artery ultrasound plaque measurement? Yes. Carotid plaque measurements guide risk decisions such as starting statins, but plaque definitions vary and ultrasound can struggle to tell benign inner-layer thickening from true atherosclerotic plaque. A second expert review of your saved ultrasound images can confirm whether the finding meets the guideline threshold of 1.5 mm or greater, whether it is protuberant or diffuse plaque, and whether the maximum plaque height was measured correctly. Because plaque reflects atherosclerosis throughout your body, correcting a misread can meaningfully change your risk classification and prevention plan. Diagnostic Detectives Network provides independent expert second opinions. --- Publisher: Diagnostic Detectives Network (https://diagnosticdetectives.com) — independent multi-expert medical second opinions, worldwide, private-pay. Author byline: Anton Titov, MD, PhD. Contact: https://diagnosticdetectives.com/pages/contact Canonical page: https://diagnosticdetectives.com/products/carotid-artery-plaque-on-ultrasound-a-patients-guide-to-the-2020-ase-guidelines-for-measuring-atherosclerosis-and-heart-risk