The experimental study of the impact factors of real-time shear wave elastography / 中华超声影像学杂志

ABSTRACT

Objective To investigate the impact factors of real-time shear wave elastography ( SWE) by using the ultrasound phantoms . Methods The noduled phantoms with different densities and viscosities and background phantoms with three textures ( soft ,medium ,and hard) were prepared by using gelatin as the main ingredient . Nodule phantoms were embedded in background phantom in different depths . The elasticity ( Emax ) was measured by SWE . Factorial designed was used to evaluate the effects of various factors ,including density ,viscosity and depth of nodule phantom and texture of background phantom on Emax of nodule phantom . Binary Logistic regression was used to analysis the effects of various factors , including density ,viscosity ,diameter ,depth of nodule phantom and texture of background phantom on the window phenomenon . Results The density ,viscosity and the Emax of nodule phantoms increased as the gelatin ratio increased . The Emax of nodule phantoms in shallow position ( depth < 3 .0 cm ) were higher than those in deep position ( depth ≥ 3 .0 cm) . In hard-background phantoms ,the Emax of nodule phantoms was maximal ,soft-background phantoms was minimal . Main effects of the density ,viscosity ,depth of nodule phantoms and texture of background phantoms on Emax of nodule phantoms were different ,and all of the factors had interactive effects ( P < 0 .05 ) . The density ,viscosity ,diameter and depth of nodule phantoms were independent risk factors of the windowphenomenon ( P < 0 .05 ) . According to OR ( 23 .846 ,0 .093 ,and 0 .003 ,respectively) ,reduced density and viscosity ,or increased diameter and depth of nodule phantoms ,could increase the incidence of the window phenomenon . Conclusions The density and viscosity of self-making ultrasound phantoms can be easily and flexibly controlled .Density ,viscosity , diameter ,depth of nodule and texture of background are the impact factors of shear wave elastography .