title: Effect of temporal acquisition parameters on image quality of strain time constant elastography.
abstract: Ultrasound methods to image the time constant (TC) of elastographic tissue parameters have been recently developed. Elastographic TC images from creep or stress relaxation tests have been shown to provide information on the viscoelastic and poroelastic behavior of tissues. However, the effect of temporal ultrasonic acquisition parameters and input noise on the image quality of the resultant strain TC elastograms has not been fully investigated yet. Understanding such effects could have important implications for clinical applications of these novel techniques. This work reports a simulation study aimed at investigating the effects of varying windows of observation, acquisition frame rate, and strain signal-to-noise ratio (SNR) on the image quality of elastographic TC estimates. A pilot experimental study was used to corroborate the simulation results in specific testing conditions. The results of this work suggest that the total acquisition time necessary for accurate strain TC estimates has a linear dependence to the underlying strain TC (as estimated from the theoretical strain-vs.-time curve). The results also indicate that it might be possible to make accurate estimates of the elastographic TC (within 10% error) using windows of observation as small as 20% of the underlying TC, provided sufficiently fast acquisition rates (>100 Hz for typical acquisition depths). The limited experimental data reported in this study statistically confirm the simulation trends, proving that the proposed model can be used as upper bound guidance for the correct execution of the experiments.
authors.affiliation: Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Nair
authors.affiliation: Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Varghese
authors.affiliation: Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
authors.forename: Anuj
authors.initials: A
authors.lastname: Chaudhry
authors.affiliation: Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA righetti@ece.tamu.edu.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Righetti
mesh_terms: D003198:Computer Simulation; D004548:Elasticity; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D010865:Pilot Projects; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D013314:Stress, Mechanical; D013997:Time Factors
keywords: biomechanics; elastography; poroelasticity; poroelastography; strain; temporal estimation; time constant; viscoelasticity