Calibration of scanning acoustic microscopy for the differentiation between unstable and stable atherosclerotic plaques by X-ray fluorescence imaging

Although cardiovascular diseases are the leading cause of death globally, un-stable atherosclerotic plaques play a vital role in plaque disruption which are related with multiple cardiovascular complications, but non-invasive and in-expensive diagnostic tools for the identification of associated unstable atheroscle-rotic plaques are not yet available. Scanning acoustic microscopy offers a high potential to fill this critical gap in patient care. However, convincing validation and calibration of this technique requires high-resolution maps of calcium concentrations of atherosclerotic plaques. In this preliminary study, a highly significant (p = 0.008) correlation between the median Ca concentra-tions and acoustic impedance values is displayed with a correlation coefficient of 0.96. Besides, we suggest that synchrotron radiation-based X-ray fluores-cence imaging with micrometer spatial resolution can provide such a gold standard for the calibration of scanning acoustic microscopy.