Ultrasound Strain Imaging for Characterizing Atherosclerotic Plaque in the Carotid Arteries of Asymptomatic Subjects

Objective

The rupture of vulnerable plaques in the carotid artery is a leading cause of strokes. While magnetic resonance imaging (MRI) is the standard for quantifying plaque composition, its high costs and lengthy procedure times limit large-scale use. Compound ultrasound strain imaging (CUSI) ultrasound offers a non-invasively alternative by assessing tissue deformation/strain within the arterial wall. Previous studies have demonstrated the relationship between strain values and plaque composition, primarily focusing on longitudinal acquisitions, which only image the proximal and distal parts of the wall. This study examines CUSI in transverse imaging planes, which enables visualization of the entire cross-section of the vessel wall. CUSI has already been validated on a symptomatic population. Therefore, the aim is to determine whether CUSI can differentiate plaque composition in asymptomatic individuals with an increased cardiovascular risk profile, validated by MRI.

Methods

This cross-sectional study included 42 plaques in 28 participants. Ultrasound data were acquired with a Samsung Medison Accuvix V10 with an L5-13IS transducer and RF-interface. An experienced neuroradiologist classified plaques with MRI using the Siemens 3.0T MAGNETOM Skyra MRI (Erlangen, Germany) with a dedicated coil. Strain differences were compared across four plaque categories (calcified, lipid, hemorrhagic, fibrous/aspecific) and for vulnerable versus stable plaques.

Results

A difference in strain values was found between lipid and calcified plaques (Kruskal–Wallis test, p < 0.05). Additionally, vulnerable plaques exhibited higher strain values than stable plaques (independent samples test, p < 0.05).

Conclusion

CUSI values differ between lipid and calcified and between stable and vulnerable plaques. Minor differences were found between the other plaque types.