Program Information
Acceptance Testing of Ultrasound Systems for Shear Wave Elastography Measurements
Z Long*, D Tradup , P Song , S Stekel , S Chen , N Hangiandreou , Mayo Clinic, Rochester, MN
Presentations
TU-H-206-9 (Tuesday, August 2, 2016) 4:30 PM - 6:00 PM Room: 206
Purpose:Acceptance testing of shear wave elastography on ten ultrasound systems is reported. Furthermore, variations in testing procedures related to coupling medium, number of operators, and phantom homogeneity were investigated.
Methods:Shear wave speed measurements were made on ten systems (GE LOGIQ E9 XDclear 2.0 ultrasound scanner with C1-6 and 9L transducers). Measurements were acquired using the CIRS Model 039 shear wave liver fibrosis phantoms (“soft” and “hard” phantoms, with stiffness of ~3.5 and 45 kPa, respectively) at two depths (3 and 7 cm for C1-6; 1 and 4 cm for 9L), by two operators. Each measurement was repeated for five times without specifying the transducer location on the phantom. 45 ppm salt water (as recommended by QIBA) was used for coupling. Furthermore, phantom homogeneity was investigated by comparing C1-6 measurements made at five positions marked on each phantom. Three operators acquired C1-6 measurements on one scanner, and one repeated the measurements after a week. US gel was compared with salt water as a coupling medium.
Results:Averaged shear wave speed using the ten C1-6 and 9L transducers are summarized in Table 1. The greatest maximum deviation of an individual measurement from the group mean (Table 2) was 5.4% of the mean and 2.3 times the standard deviation among all groups. Salt water and US coupling gel showed no significant difference. Velocities from the five measurement locations had a maximum deviation of 5.9% or less. The maximum inhomogeneity averaged over the two phantoms and all measurement locations was 2.6%. Inter- and intra-operator coefficients of variation were all ≤ 2.2%.
Conclusion:The measurement variations were considered to be reasonable, and all equipment was accepted. The use of salt water versus gel for acoustic coupling, single versus multiple phantom measurement locations, or single versus multiple operators would not cause significant differences in acceptance test results.
Funding Support, Disclosures, and Conflict of Interest: Pengfei Song and Shigao Chen receive royalties from GE Medical Systems for the shear wave elastography technology.
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