Inter-platform reproducibility of ultrasonic attenuation and backscatter coefficients in assessing NAFLD - PubMed (original) (raw)

Inter-platform reproducibility of ultrasonic attenuation and backscatter coefficients in assessing NAFLD

Aiguo Han et al. Eur Radiol. 2019 Sep.

Abstract

Objectives: To assess inter-platform reproducibility of ultrasonic attenuation coefficient (AC) and backscatter coefficient (BSC) estimates in adults with known/suspected nonalcoholic fatty liver disease (NAFLD).

Methods: This HIPAA-compliant prospective study was approved by an institutional review board; informed consent was obtained. Participants with known/suspected NAFLD were recruited and underwent same-day liver examinations with clinical ultrasound scanner platforms from two manufacturers. Each participant was scanned by the same trained sonographer who performed multiple data acquisitions in the right liver lobe using a lateral intercostal approach. Each data acquisition recorded a B-mode image and the underlying radio frequency (RF) data. AC and BSC were calculated using the reference phantom method. Inter-platform reproducibility was evaluated for AC and log-transformed BSC (logBSC = 10log10BSC) by intraclass correlation coefficient (ICC), Pearson's correlation, Bland-Altman analysis with computation of limits of agreement (LOAs), and within-subject coefficient of variation (wCV; applicable to AC).

Results: Sixty-four participants were enrolled. Mean AC values measured using the two platforms were 0.90 ± 0.13 and 0.94 ± 0.15 dB/cm/MHz while mean logBSC values were - 30.6 ± 5.0 and - 27.9 ± 5.6 dB, respectively. Inter-platform ICC was 0.77 for AC and 0.70 for log-transformed BSC in terms of absolute agreement. Pearson's correlation coefficient was 0.81 for AC and 0.80 for logBSC. Ninety-five percent LOAs were - 0.21 to 0.13 dB/cm/MHz for AC, and - 9.48 to 3.98 dB for logBSC. The wCV was 7% for AC.

Conclusions: Hepatic AC and BSC are reproducible across two different ultrasound platforms in adults with known or suspected NAFLD.

Key points: • Ultrasonic attenuation coefficient and backscatter coefficient are reproducible between two different ultrasound platforms in adults with NAFLD. • This inter-platform reproducibility may qualify quantitative ultrasound biomarkers for generalized clinical application in patients with suspected/known NAFLD.

Keywords: Nonalcoholic fatty liver disease; Phantoms, imaging; Prospective studies; Reproducibility of results; Ultrasonography.

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Conflict of interest statement

Conflict of Interest:

The authors of this manuscript declare relationships with the following companies:

The work is supported in part by research grants from Siemens Healthineers USA and GE Healthcare. The use of the Siemens S3000 scanner was loaned to the University of California San Diego under a research agreement with Siemens Healthineers USA. The use of the GE Logiq E9 scanner was loaned to the University of California San Diego under a research agreement with GE Healthcare.

Figures

Figure 1.

Figure 1.

Representative liver B-mode images reconstructed from the radio-frequency data acquired from a 51 years old male using (a) GE Logiq E9 and (b) Siemens S3000 clinical ultrasound scanners. The magenta field of interest lines were drawn on the reconstructed B-mode images to outline the liver boundary.

Figure 2.

Figure 2.

(a) Scatter plot shows relationship between attenuation coefficient (AC) values measured from GE Logiq E9 and Siemens S3000. (b) Bland-Altman plot shows agreement between AC values measured using the two platforms. Thick red dashed line shows the mean difference in AC values between the two platforms and thick blue dashed lines demarcate ± 1.96 standard deviations (SD), with associated 95% confidence intervals indicated by thin dashed lines. The AC values in both plots were obtained by averaging five intra-platform repeated acquisitions per participant.

Figure 3.

Figure 3.

(a) Scatter plot shows relationship between log-transformed backscatter coefficient (logBSC) values measured from GE Logiq E9 and Siemens S3000. (b) Bland-Altman plot shows agreement between logBSC values measured using the two platforms. Thick red dashed line shows the mean difference in logBSC values between the two platforms and thick blue dashed lines demarcate ± 1.96 standard deviations (SD), with associated 95% confidence intervals indicated by thin dashed lines. The logBSC values in both plots were obtained by averaging five intra-platform repeated acquisitions per participant.

Figure 4.

Figure 4.

Absolute between-platform difference in QUS biomarker versus participant condition plots (a: AC absolute difference versus BMI; b: logBSC absolute difference versus BMI; c: AC absolute difference versus skin-to-capsule distance; d. logBSC absolute difference versus skin-to-capsule distance) show that the QUS inter-platform variability is not significantly affected by the participant BMI or subcutaneous fat. The corresponding Pearson’s correlation and p value are displayed in each subfigure.

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