Points to be considered when applying FibroScan S probe in children with biliary atresia

Abstract

Objectives: With the introduction of smaller probes (S1, S2), the use of transient elastography has been expanded to children. Accordingly, we aimed to address points of consideration in probe choice and interpretation of measured liver stiffness by applying and comparing FibroScan S and M probes in biliary atresia.

Methods: Using S1, S2, and M probes, 3 liver stiffness measurements, success rates, and interquartile ranges were obtained from 100 patients. Patients were assigned to 2 groups according to thoracic perimeter (≤ 45 cm vs > 45 cm). In both groups, obtained values were compared and the relation between liver stiffness measurement and aspartate aminotransferase-to-platelet ratio index was analyzed.

Results: In the small-thorax group, the success rate was highest with the S1 probe and the intraclass correlation coefficient (ICC) was highest for S1 versus S2 (0.98), compared with that for S1 versus M (0.69) and S2 versus M (0.77). In the large-thorax group, ICC was the highest for S2 versus M (0.88), compared with that for S1 versus S2 (0.69) and S1 versus M (0.51). In the small-thorax group, correlations between aspartate aminotransferase-to-platelet ratio index and liver stiffness measurement were stronger for S1 (0.65) and S2 (0.64) than for M (0.49). In the large-thorax group, all probes showed good correlation, S1 (0.68), S2 (0.62), and M (0.62).

Conclusions: We recommend that the S1 probe is more appropriate for use in small children, especially those with a thorax perimeter of < 45 cm. If no S probe is available, the M probe may be acceptable in children whose thorax perimeter is > 45 cm.

Conflict of interest statement

The authors report no conflicts of interest.

Figures

FIGURE 1

Success rates (A) and IQR/LSM ratios (B) of S1, S2, and M probes in the large thoracic perimeter group and the small thoracic perimeter group. (∗) Success rate of the S1 probe was significantly higher than that of the M probe in the small thoracic perimeter group (P = 0.0016). The IQR/LSM ratio among probes in both groups was not significantly different. Data are expressed as mean ± standard deviation. IQR = interquartile range; LSM = liver stiffness measurement.

FIGURE 2

Bland-Altman plot of the difference in LSM by 2 different probes versus the mean of LSM. The solid lines indicate mean difference, and dotted lines represent 2 standard deviations between 2 probes. A, S1 and S2, 5.2 ± 16.8 kPa; (B) S1 and M, 8.3 ± 22.3 kPa; and (C) S2 and M, 3.0 ± 11.8 kPa. Outliers are noted in patients with high mean LSM. LSM = liver stiffness measurement.

FIGURE 3

Correlations among LSMs determined using various probes. A, S1 and M; (B) S2 and M. LSM determined using S1 and S2 probes was higher than that determined using the M probe. LSM = liver stiffness measurement.

FIGURE 4

Box-and-whisker plot of LSM showing distributions of LSM according to the probe. The box represents the interquartile range, and the line in the box shows the median value. The whiskers indicate the highest and lowest values, and the circles represent outliers. LSM = liver stiffness measurement.