Shear Wave Elastography and Quantitative Ultrasound as Biomarkers to Characterize Deep Vein Thrombosis In Vivo

Abstract

Objective Investigate shear wave elastography (SWE) and quantitative ultrasound (QUS) parameters in patients hospitalized for lower limb deep vein thrombosis (DVT). Method Sixteen patients with DVT were recruited and underwent SWE and radiofrequency data acquisitions for QUS on day 0, day 7, and day 30 after the beginning of symptoms, in both proximal and distal zones of the clot identified on B‐mode scan. SWE and QUS features were computed to differentiate between thrombi at day 0, day 7, and day 30 following treatment with heparin or oral anticoagulant. The Young's modulus from SWE was computed, as well as QUS homodyned K‐distribution (HKD) parameters reflecting blood clot structure. Median and interquartile range of SWE and QUS parameters within clot were taken as features. Results In the proximal zone of the clot, the HKD ratio of coherent‐to‐diffuse backscatter median showed a significant decrease from day 7 to day 30 (P = .036), while the HKD ratio of diffuse‐to‐total backscatter median presented a significant increase from day 7 to day 30 (P = .0491). In the distal zone of the clot, the HKD normalized intensity of the echo envelope median showed a significant increase from day 0 to day 30 (P = .0062). No SWE features showed statistically significant differences over time. Nonetheless, a trend of lower median of Young's modulus within clot for patients who developed a pulmonary embolism was observed. Conclusion QUS features may be relevant to characterize clot's evolution over time. Further analysis of their clinical interpretation and validation on a larger dataset would deserve to be studied.

Resonance, Velocity, Dispersion, and Attenuation of Ultrasound‐Induced Shear Wave Propagation in Blood Clot In Vitro Models

“…This increase is a characteristic of clot aging. However, under clinical conditions, patients, once diagnosed, are treated with anticoagulants, and no time‐varying trend in Young modulus has been observed 50 . The variability, characterized by the standard deviations, reflects the difference in coagulation between pigs.…”

“…However, under clinical conditions, patients, once diagnosed, are treated with anticoagulants, and no time-varying trend in Young modulus has been observed. 50 The variability, characterized by the standard deviations, reflects the difference in coagulation between pigs. Parameters that may have played a role in this variability include the sex of the pigs, which was not specified, and the time between blood sampling and the start of the experiments, which could vary from a few minutes to 1 hour.…”

“…The elasticity increase has also been linked with thrombus resistance to lysis 49 . Other teams have focused on the impact of treatments on mechanical properties, however, results on Young modulus alone have not reached a consensus 50,51 . In their work using ARFIRE, Bhatt et al 16 showed with simulated data that the first resonance peak increases in frequency as the elasticity of the inclusion is raised.…”

Spectral-based Quantitative Ultrasound Imaging Processing Techniques: Comparisons of RF Versus IQ Approaches

“…22,23 To estimate the BSC or ACS, traditionally the IQ data is converted back into RF data first, and then the QUS parameters are estimated from the RF. 24,25 However, because the power spectrum from the IQ data and RF data are similar to each other, and QUS is a spectral-based method, it is reasonable that the IQ data could be used to calculate QUS parameters without a loss in information. Furthermore, every time the RF data is converted to IQ or IQ converted back to RF, potential artifacts can appear caused by phase imbalance, local oscillator leakage, and/or local oscillator phase noise.…”

Elastometry of clot phantoms via magnetomotive ultrasound-based resonant acoustic spectroscopy

“…Quantitative ultrasound elastometry-the measure of elasticity, often in terms of Young's modulus-may rapidly inform DVT treatment decisions by providing a classification of the thrombus as acute or chronic. Current methods of ultrasound clot elastometry are in development (Bosio et al 2021), but not yet standardized, and could benefit from a contrast-enhanced technique due to the low echogenicity of many thrombi. Originally developed from optical coherence tomography (OCT) (Oldenburg et al 2005), and recently investigated for its ability to label thrombi (Pope et al 2013, Levy et al 2018, magnetomotive ultrasound (MMUS) is an emerging imaging modality in which magnetic nanoparticles (MNPs) are used as a contrast agent (Oh et al 2006, Sjöstrand et al 2020.…”