Prediction of the biomechanical effects of compression therapy by finite element modeling and ultrasound elastography.

Abstract

In the present study, the biomechanical response of soft tissues from the fascia cruris to the skin is studied in the human leg under elastic compression. The distribution of elastic moduli in these tissues is measured for a volunteer at inactive and active muscle states using transient ultrasound elastography (TUSE). After registering the elasticity maps against magnetic resonance imaging scans of the same volunteer, patient-specific finite element (FE) models are developed for the leg cross section at inactive and active muscle states. Elastic properties obtained with TUSE are assigned at each Gauss point of the models. The response to 20 mmHg elastic compression is eventually predicted with the models. Results show significantly higher elastic moduli in the fascia cruris tissue and also a significant increase of elastic moduli at active muscle state. This seems to have a marginal impact on pressure maps in the soft tissues of the leg predicted by the FE models. There is still an effect on the reduction of vein diameter induced by elastic compression, which is decreased at active muscle state. The discussion of this paper highlights the benefits of using elastography to reconstruct patient-specific FE models of soft tissues.