title: Improved Estimation of Ultrasound Thermal Strain Using Pulse Inversion Harmonic Imaging.
abstract: Thermal (temporal) strain imaging (TSI) is being developed to detect the lipid-rich core of atherosclerotic plaques and presence of fatty liver disease. However, the effects of ultrasonic clutter on TSI have not been considered. In this study, we evaluated whether pulse inversion harmonic imaging (PIHI) could be used to improve estimates of thermal (temporal) strain. Using mixed castor oil-gelatin phantoms of different concentrations and artificially introduced clutter, we found that PIHI improved the signal-to-noise ratio of TSI by an average of 213% or 52.1% relative to 3.3- and 6.6-MHz imaging, respectively. In a phantom constructed using human liposuction fat in the presence of clutter, the contrast-to-noise ratio was degraded by 35.1% for PIHI compared with 62.4% and 43.7% for 3.3- and 6.6-MHz imaging, respectively. These findings were further validated using an ex vivo carotid endarterectomy sample. PIHI can be used to improve estimates of thermal (temporal) strain in the presence of clutter.
authors.affiliation: Department of Bioengineering, University of Pittsburgh School of Engineering, Pittsburgh, Pennsylvania, USA; Medical Scientist Training Program, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, Pennsylvania, USA; Department of Medicine and Heart and Vascular Institute, Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Xuan
authors.initials: X
authors.lastname: Ding
authors.affiliation: Department of Medicine and Heart and Vascular Institute, Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Man M
authors.initials: MM
authors.lastname: Nguyen
authors.affiliation: Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
authors.forename: Isaac B
authors.initials: IB
authors.lastname: James
authors.affiliation: Department of Bioengineering, University of Pittsburgh School of Engineering, Pittsburgh, Pennsylvania, USA; Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Kacey G
authors.initials: KG
authors.lastname: Marra
authors.affiliation: Department of Bioengineering, University of Pittsburgh School of Engineering, Pittsburgh, Pennsylvania, USA; Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: J Peter
authors.initials: JP
authors.lastname: Rubin
authors.affiliation: Department of Vascular Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Leers
authors.affiliation: Department of Bioengineering, University of Pittsburgh School of Engineering, Pittsburgh, Pennsylvania, USA; Department of Medicine and Heart and Vascular Institute, Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh and University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA. Electronic address: kangkim@upmc.edu.
authors.forename: Kang
authors.initials: K
authors.lastname: Kim
mesh_terms: D000465:Algorithms; D054459:Elasticity Imaging Techniques / Q000295:instrumentation / Q000379:methods*; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013817:Thermography / Q000295:instrumentation / Q000379:methods*
keywords: Non-invasive ultrasound thermometry; Oil–gelatin phantom; Pulse inversion harmonic imaging; Temporal strain imaging; Thermal strain imaging; Ultrasound clutter