Background/Objectives: Ultrasound shear-wave elastography (SWE) enables quantitative assessment of tissue stiffness and may provide a non-invasive biomarker of carotid plaque vulnerability. This study aimed to evaluate the ability of SWE to differentiate symptomatic from asymptomatic carotid plaques and to assess its reproducibility. Methods: A systematic search of PubMed, Web of Science, EMBASE, and the Cochrane Library was conducted in the last ten years until January 2026 for publications evaluating carotid plaques using ultrasound SWE. Inclusion criteria required original publications that used quantitative ultrasound SWE parameters for the evaluation of carotid plaque in symptomatic and asymptomatic patients and/or investigated the reproducibility of SWE parameters for carotid plaques; non-carotid studies, non-original articles, and studies not comparing symptomatic versus asymptomatic plaques or not reporting reproducibility were excluded. Fourteen studies comprising 1781 carotid plaques were included. Quantitative SWE measurements were meta-analyzed using random effects. Differences between symptomatic and asymptomatic plaques were assessed using standardized mean differences (SMDs). The reproducibility of SWE measurements was evaluated using pooled correlation coefficients. Publication bias was evaluated using funnel plots and Egger’s regression test. Results: Ten studies including 1246 plaques compared SWE stiffness between symptomatic (n = 472) and asymptomatic plaques (n = 774). The meta-analysis demonstrated significantly lower stiffness values in symptomatic plaques compared with asymptomatic plaques (SMD −1.10, p < 0.001). Reproducibility analysis of correlation coefficients extracted from seven studies demonstrated excellent agreement for SWE measurements (r = 0.92, n = 602). Heterogeneity was observed across the included studies. No statistically significant evidence of publication bias was detected. Conclusions: Ultrasound SWE is a promising approach for assessing carotid plaque vulnerability, with lower SWE stiffness observed in symptomatic plaques compared to asymptomatic plaques. This finding should be interpreted with consideration of methodological heterogeneity and the cross-sectional nature of the available assessed evidence. Further prospective studies with standardized imaging protocols and longitudinal follow-up are needed to determine clinically applicable stiffness thresholds and evaluate the prognostic value of ultrasound SWE in cerebrovascular risk stratification.

Background: Vascular ultrasound enables non-invasive assessment of lower-limb arterial morphology and hemodynamics and may identify vascular abnormalities associated with type 2 diabetes mellitus (T2DM). This study aimed to determine whether ultrasound-derived morphological and hemodynamic parameters differ between patients with T2DM and non-diabetic controls. Methods: PubMed, Web of Science, EMBASE, and the Cochrane Library were systematically searched for studies published within the preceding 10 years up to June 2026. Eligible studies were original publications that quantitatively compared lower-limb arterial morphology and/or hemodynamics between adults with T2DM and non-diabetic controls using ultrasound imaging. Four studies comprising 708 participants and 2069 artery-level assessments were included. Ultrasound parameters were meta-analyzed using random-effects models, and between-group differences were evaluated using standardized mean differences (SMDs). Results: The pooled analyses demonstrated no statistically significant differences between patients with T2DM and non-diabetic controls in either morphological (SMD 0.23, 95% CI −0.14 to 0.61; p = 0.227) or hemodynamic parameters (SMD −0.14, 95% CI −0.36 to 0.09; p = 0.227). Heterogeneity was observed in both the morphological and hemodynamic analyses (I² = 93% and 83%, respectively). Conclusions: Based on the available evidence, the pooled analyses identified no statistically significant overall differences in lower-limb arterial morphological or hemodynamic parameters between patients with T2DM and non-diabetic controls. The available evidence is limited by heterogeneous imaging methods and correlated artery-level measurements. Prospective multicentre studies using standardized imaging protocols and segment-specific analyses are required to clarify the clinical value of ultrasound for detecting early lower-limb vascular dysfunction in T2DM.