title: Ultrasound speckle tracking for radial, longitudinal and circumferential strain estimation of the carotid artery--an in vitro validation via sonomicrometry using clinical and high-frequency ultrasound.
abstract: Ultrasound speckle tracking for carotid strain assessment has in the past decade gained interest in studies of arterial stiffness and cardiovascular diseases. The aim of this study was to validate and directly contrast carotid strain assessment by speckle tracking applied on clinical and high-frequency ultrasound images in vitro. Four polyvinyl alcohol phantoms mimicking the carotid artery were constructed with different mechanical properties and connected to a pump generating carotid flow profiles. Gray-scale ultrasound long- and short-axis images of the phantoms were obtained using a standard clinical ultrasound system, Vivid 7 (GE Healthcare, Horten, Norway) and a high-frequency ultrasound system, Vevo 2100 (FUJIFILM, VisualSonics, Toronto, Canada) with linear-array transducers (12L/MS250). Radial, longitudinal and circumferential strains were estimated using an in-house speckle tracking algorithm and compared with reference strain acquired by sonomicrometry. Overall, the estimated strain corresponded well with the reference strain. The correlation between estimated peak strain in clinical ultrasound images and reference strain was 0.91 (p<0.001) for radial strain, 0.73 (p<0.001) for longitudinal strain and 0.90 (p<0.001) for circumferential strain and for high-frequency ultrasound images 0.95 (p<0.001) for radial strain, 0.93 (p<0.001) for longitudinal strain and 0.90 (p<0.001) for circumferential strain. A significant larger bias and root mean square error was found for circumferential strain estimation on clinical ultrasound images compared to high frequency ultrasound images, but no significant difference in bias and root mean square error was found for radial and longitudinal strain when comparing estimation on clinical and high-frequency ultrasound images. The agreement between sonomicrometry and speckle tracking demonstrates that carotid strain assessment by ultrasound speckle tracking is feasible.
authors.affiliation: Department of Medical Engineering, School of Technology and Health, KTH Royal Institute of Technology, Stockholm, Alfred Nobels Allé 10, 141 52 Huddinge, Sweden; Lab on Cardiovascular Imaging & Dynamics, KU Leuven, Campus Gasthuisberg O&N1, Herestraat 49 box 911, 3000 Leuven, Belgium. Electronic address: matilda.larsson@sth.kth.se.
authors.forename: Matilda
authors.initials: M
authors.lastname: Larsson
authors.affiliation: Lab on Cardiovascular Imaging & Dynamics, KU Leuven, Campus Gasthuisberg O&N1, Herestraat 49 box 911, 3000 Leuven, Belgium.
authors.forename: Brecht
authors.initials: B
authors.lastname: Heyde
authors.affiliation: Lab on Cardiovascular Imaging & Dynamics, KU Leuven, Campus Gasthuisberg O&N1, Herestraat 49 box 911, 3000 Leuven, Belgium.
authors.forename: Florence
authors.initials: F
authors.lastname: Kremer
authors.affiliation: Department of Medical Engineering, School of Technology and Health, KTH Royal Institute of Technology, Stockholm, Alfred Nobels Allé 10, 141 52 Huddinge, Sweden.
authors.forename: Lars-Åke
authors.initials: LÅ
authors.lastname: Brodin
authors.affiliation: Lab on Cardiovascular Imaging & Dynamics, KU Leuven, Campus Gasthuisberg O&N1, Herestraat 49 box 911, 3000 Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: D'hooge
mesh_terms: D000465:Algorithms; D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000502:physiology; D006801:Humans; D019047:Phantoms, Imaging; D014463:Ultrasonography
keywords: Carotid strain; High-frequency ultrasound; Sonomicrometry; Ultrasound speckle tracking; Vessel phantom