Ultraschall Med 2016; 37 - P4_27
DOI: 10.1055/s-0036-1587947

Quantification of tissue elasticity using three shear wave elastography platforms on liver fibrosis phantoms

A Mulabecirovic 1, 2, A Batman Mjelle 2, OH Gilja 1, 2, 3, R Flesland Havre 1, 2, 3
  • 1Haukeland University Hospital, Department of Medicine, Bergen, Norway
  • 2Haukeland University Hospital, National Centre for Ultrasound in Gastroenterology, Bergen, Norway
  • 3University of Bergen, Department of Clinical Medicine, Bergen, Norway

Purpose: To assess the reproducibility of quantitative shear-wave elastography measurements, on four tissue-mimicking liver fibrosis phantoms with known Young's modulus.

Materials and methods: We used three different shear wave elastography platforms: GE Logiq E9 SWE, Philips iu22 XM ARFI and Samsung RS80A. Both linear (frequency:9 MHz) and curvilinear (frequency: 7 – 1 MHz) probes were applied. The objects were four separate tissue mimicking liver fibrosis phantoms with different Young's modulus within the range of biological soft tissue (2.7kPa, 11.5kPa, 24.8kPa, 46.3kPa). Two investigators performed all measurements in parallel. Each investigator made 10 separate measurements of each phantom. The results were evaluated for inter- and intraobserver variability, coefficient of variation, ICC and Bland-Altman using the median value for each platform. Statistical analysis was performed with SPSS.

Results: All three elastography platforms showed excellent intraobserver agreement (ICC: 0.987 – 1.000) and interobserver agreement (ICC: 0.981 – 1.000). All four liver fibrosis phantoms could be differentiated by quantitative elastography, by all platforms (p < 0.001). In the Bland-Altman analysis the differences in measurements were larger for the phantoms with higher Young's modulus. All platforms had a coefficient of variation in the range 0.00 – 0.21 for all four phantoms, equivalent to low variance and high reproducibility (Table 1).

Median (min-max) elasticity measurements performed with three elastographyplatforms on liver fibrosis phantoms.

Tab. 1

Elastography system

Probe

shape

Observer

Phantom 1

2.7 kPa ± 5%

Phantom 2

11.5 kPa ± 5%

Phantom 3

24.8 kPa ± 5%

Phantom 4

46.3 kPa ± 5%

Philips iu22

XM ARFI

A

l.93kPa

(1.76 – 2.23)

8.29 kPa

(7.35 – 9.66)

20.46 kPa

(18.2 – 34.88)

47.09 kPa

(38.29 – 50.75)

curvilinear

B

1.89 kPa

(1.8 – 2.01)

7.73 kPa

(7.23 – 7.92)

19.68kPa

(18.88 – 23.9)

44.74 kPa

(36.73 – 46.85)

A+ B

1.9 kPa

(1.76 – 2.23)

7.82kPa

(7.23 – 9.66)

20.19 kPa

(18.2 – 34.88)

45.5 kPa

(36.73 – 50.75)

Samsung

RS80A SWE

A

2.1 kPa

(2 – 2.3)

7.6 kPa

(7.2 – 8.9)

18.40 kPa

(17 – 20)

43.85kPa

(40.9 – 45.8)

curvilinear

B

2.1 kPa

(2 – 2.2)

7.65 kPa

(7 – 8.1)

18.15kPa

(17.6 – 20.7)

43.65 kPa

(40.9 – 47.8)

A – B

2.1 kPa

(2 – 2.3)

7.6 kPa

(7 – 8.9)

18.30 kPa

(17 – 20.7)

43.7 kPa

(40.9 – 47.8)

GE E9 Logiq

SWT

A

l.9kPa

(1.85 – 2.98)

7.02kPa

(6.98 – 7.09)

17.06kPa

(16.9 – 17.16)

35.93 kPa

(35.52 – 36.47)

linear

B

1.97 kPa

(1.93 – 2.05)

6.88 kPa

(6.79 – 6.91)

17.05kPa

(16.83 – 17.27)

36.47 kPa

(36.3 – 36.82)

A+B

1.89 kPa

(1.85 – 2.98)

6.94 kPa

(6.79 – 7.09)

17.06kPa

(16.83 – 17 – 27)

36.37 kPa

(35.52 – 36.82)

A

1.86 kPa

(1.83 – 1.94)

7.24 kPa

(7.15 – 7.28)

18.92 kPa

(18.25 – 19.52)

39.44 kPa

(38.5 – 40.44)

curvilinear

B

1.92 kPa

(1.85 – 1.94)

7.21kPa

(7.15 – 7.23)

18.47 kPa

(17.96 – 18.97)

38.67kPa

(37.84 – 39.54)

A+B

1.95 kPa

(1.83 – 1.94)

7.23 kPa

(7.15 – 7.28)

18.75 kPa

(17.96 – 19.52)

38.9 kPa

(37.84 – 40.44)

Conclusion: All systems used in this study obtained high reproducibility in quantitative measurements in a liver fibrosis phantom and excellent interclass correlations.