Vulnerable Carotid Plaque: GSM, Ulceration, and Neovascularization in CEUS
Morphology Over Percentages
The degree of stenosis determines indications for revascularization, but plaque morphology clarifies individual risk — this is the modern focus. A hypoechoic plaque (low GSM, large juxtaluminal hypoechoic area) with ulceration, even with 'moderate' stenosis, can be a source of emboli. The plaque should be described as meticulously as the percentage of stenosis is calculated.
GSM and Grayscale Analysis
Assessment of plaque structure in grayscale (GSM) is part of the vulnerability characterization. According to ACSRS (Kakkos S.K. et al., 2013), the size of the juxtaluminal hypoechoic area in ultrasound of asymptomatic carotid plaques predicts stroke occurrence. Plaque area (ASE, 2020) is a more accurate indicator of overall plaque burden than height, better differentiating eccentric or large layered plaques from small protruding ones.
Surface Ulceration
The criterion for an ulcer is a niche ≥2 mm in depth and width [source 1997;7:289–296]. The plaque surface is classified as smooth/irregular (0.3–0.9 mm) or ulcerated. Ulceration is among the reproducibly accessible signs in routine duplex (along with thickness and partly structure).
| Method | Sensitivity to Ulcer |
|---|---|
| CEUS | ~88 % |
| Ultrasound (without contrast) | ~29 % |
Neovascularization in CEUS
Contrast-enhanced ultrasound (CEUS) allows visualization of intraplaque neovascularization (IPN) and vasa vasorum. Intraplaque vessels via CEUS predict carotid plaque histology (Amamoto T. et al., 2018). A 3-point scale is used to assess IPN (Narrative Review, Diagnostics, 2023). Neovascularization and intraplaque hemorrhage contribute to the progression and instability of atherosclerotic plaque (Chistiakov D.A. et al., 2015). Quantitative assessment of microvascular blood flow and vasa vasorum via CEUS is possible (Greis C., 2011; Vavuranakis M. et al., 2013).
Place in the Plaque-RADS System
Plaque-RADS today is primarily a systematizing and research tool; only part of its features (thickness, ulceration, partly structure) are reproducibly accessible in routine duplex.
Frequently asked questions
What criterion should be used for plaque ulceration?
A niche ≥2 mm in depth and width [source 1997;7:289–296]. The surface is described as smooth/irregular (0.3–0.9 mm) or ulcerated.
How much more sensitive is CEUS to ulcers compared to regular ultrasound?
CEUS sensitivity to ulcers is about 88% compared to about 29% with ultrasound without contrast (Front Cardiovasc Med, 2022).
What does the assessment of GSM and the juxtaluminal area provide?
The size of the juxtaluminal hypoechoic area in ultrasound of asymptomatic carotid plaques predicts stroke occurrence (ACSRS, Kakkos S.K. et al., 2013). Low GSM indicates vulnerability.
How does CEUS assess neovascularization?
CEUS visualizes intraplaque neovascularization (IPN); a 3-point IPN scale is used (Diagnostics, 2023). Intraplaque vessels via CEUS predict plaque histology (Amamoto T. et al., 2018).
Does morphology change indications for revascularization?
The degree of stenosis determines indications for revascularization, while plaque morphology clarifies risk. A hypoechoic plaque with ulceration in moderate stenosis can be a source of emboli.