title: Interlaboratory comparison of backscatter coefficient estimates for tissue-mimicking phantoms.
abstract: Ultrasonic backscatter is useful for characterizing tissues and several groups have reported methods for estimating backscattering properties. Previous interlaboratory comparisons have been made to test the ability to accurately estimate the backscatter coefficient (BSC) by different laboratories around the world. Results of these comparisons showed variability in BSC estimates but were acquired only for a relatively narrow frequency range, and, most importantly, lacked reference to any independent predictions from scattering theory. The goal of this study was to compare Faran-scattering-theory predictions with cooperatively-measured backscatter coefficients for low-attenuating and tissue-like attenuating phantoms containing glass sphere scatterers of different sizes for which BSCs can independently be predicted. Ultrasonic backscatter measurementswere made for frequencies from 1 to 12 MHz. Backscatter coefficients were estimated using two different planar-reflector techniques at two laboratories for two groups of phantoms. Excellent agreement was observed between BSC estimates from both laboratories. In addition, good agreement with the predictions of Faran's theory was obtained, with average fractional (bias) errors ranging from 8-14%. This interlaboratory comparison demonstrates the ability to accurately estimate parameters derived from the BSC, including an effective scatterer size and the acoustic concentration, both of which may prove useful for diagnostic applications of ultrasound tissue characterization.
authors.affiliation: University of Wisconsin-Madison, Wisconsin Institutes for Medical Research, 1111 Highland Ave., Madison, WI 53705, USA.
authors.forename: Janelle J
authors.initials: JJ
authors.lastname: Anderson
authors.forename: Maria-Teresa
authors.initials: MT
authors.lastname: Herd
authors.forename: Michael R
authors.initials: MR
authors.lastname: King
authors.forename: Alexander
authors.initials: A
authors.lastname: Haak
authors.forename: Zachary T
authors.initials: ZT
authors.lastname: Hafez
authors.forename: Jun
authors.initials: J
authors.lastname: Song
authors.forename: Michael L
authors.initials: ML
authors.lastname: Oelze
authors.forename: Ernest L
authors.initials: EL
authors.lastname: Madsen
authors.forename: James A
authors.initials: JA
authors.lastname: Zagzebski
authors.forename: William D
authors.initials: WD
authors.lastname: O'Brien
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Hall
mesh_terms: D000818:Animals; D004867:Equipment Design; D005780:Gelatin; D005898:Glass; D008892:Milk; D019047:Phantoms, Imaging; D012815:Signal Processing, Computer-Assisted; D014159:Transducers; D014465:Ultrasonics; D014463:Ultrasonography / Q000592:standards*; D014867:Water
chemical_list: D014867:Water; D005780:Gelatin