Normal values of shear wave velocity in liver tissue of healthy children measured using the latest acoustic radiation force impulse technology

Table 1 Description of the subjects

	Female (%)	Male (%)	All	P value
	116 (42.6)	86 (57.4)	202
Age
Mean ± SD (yr)	7.2 ± 3.4	6.3 ± 4.0	6.8 ± 3.7	0.081
Range	0.1-15	0.1-15	0.1-15
BMI
Mean ± SD (kg/m2)	16.7 ± 2.6	16.4 ± 1.6	16.6 ± 2.1	0.335
Range	13.8-25.5	13.2-24.2	13.2-25.5

SD: Standard deviation; BMI: Body mass index.

Table 2 Shear wave velocity measured by virtual touch imaging quantification in patients of different gender

Liver lobe/depth	Male		Female		P value
	Mean ± SD	95%CI	Mean ± SD	95%CI
Left/1.5 cm	2.56 ± 0.41	2.46-2.66	2.58 ± 0.47	2.47-2.68	0.788
Left/2.0 cm	2.15 ± 0.44	2.05-2.24	2.06 ± 0.37	2.00-2.13	0.144
Left/2.5 cm	1.77 ± 0.27	1.71-1.83	1.77 ± 0.30	1.71-1.82	0.901
Left/3.0 cm	1.64 ± 0.19	1.60-1.69	1.66 ± 0.25	1.61-1.72	0.565
Right/1.5 cm	2.51 ± 0.33	2.42-2.60	2.55 ± 0.44	2.45-2.65	0.591
Right/2.0 cm	2.10 ± 0.33	2.03-2.18	2.10 ± 0.37	2.04-2.17	0.982
Right/2.5 cm	1.75 ± 0.28	1.69-1.81	1.74 ± 0.29	1.69-1.79	0.752
Right/3.0 cm	1.66 ± 0.22	1.60-1.72	1.61 ± 0.25	1.55-1.67	0.284

VTIQ: Virtual touch imaging quantification; SD: Standard deviation; CI: Confidence interval.

Table 3 Effect of age on shear wave velocity measured in different hepatic lobes and at different depths

Liver lobe/depth	Age group (yr)				P value	Compar-ison	P value
	Group 1 (n = 28)	Group 2 (n = 68)	Group 3 (n = 58)	Group 4 (n = 48)
Left/1.5 cm					0.038
Mean ± SD	2.41 ± 0.40	2.53 ± 0.40	2.70 ± 0.46	2.63 ± 0.53		G1-G3	0.038
95%CI	2.25-2.56	2.43-2.63	2.56-2.85	2.34-2.92
Left/2.0 cm					0.002
Mean ± SD	1.92 ± 0.25	2.07 ± 0.39	2.08 ± 0.29	2.27 ± 0.55		G1-G4	0.002
95%CI	1.82-2.02	1.97-2.16	2.01-2.16	2.11-2.43		G2-G4	0.042
Left/2.5 cm					0.116
Mean ± SD	1.69 ± 0.23	1.75 ± 0.28	1.76 ± 0.26	1.84 ± 0.33
95%CI	1.60-1.78	1.69-1.82	1.69-1.83	1.75-1.94
Left/3.0 cm					0.091
Mean ± SD	1.56 ± 0.15	1.65 ± 0.21	1.68 ± 0.25	1.69 ± 0.24
95%CI	1.49-1.62	1.58-1.72	1.60-1.75	1.62-1.77
Right/1.5 cm					0.160
Mean ± SD	2.37 ± 0.29	2.53 ± 0.41	2.61 ± 0.44	2.57 ± 0.38
95%CI	2.25-2.50	2.41-2.65	2.46-2.75	2.41-2.72
Right/2.0 cm					0.131
Mean ± SD	1.98 ± 0.22	2.09 ± 0.36	2.12 ± 0.30	2.18 ± 0.43
95%CI	1.90-2.07	2.00-2.18	2.04-2.20	2.05-2.30
Right/2.5 cm					0.419
Mean ± SD	1.69 ± 0.23	1.75 ± 0.29	1.73 ± 0.23	1.79 ± 0.35
95%CI	1.60-1.77	1.68-1.82	1.67-1.79	1.69-1.90
Right/3.0 cm					0.061
Mean ± SD	1.53 ± 0.24	1.65 ± 0.32	1.59 ± 0.18	1.70 ± 0.22
95%CI	1.42-1.65	1.52-1.78	1.53-1.66	1.63-1.76

G1-G4: Groups 1-4. Significant differences are highlighted in boldface.

Table 4 Effect of body mass index on shear wave velocity measured in different hepatic lobes and at different depths

Liver lobe/depth	BMI group (kg/m2)				P value
	<15 (n = 23)	15-16 (n = 65)	16-17 (n = 54)	>17 (n = 60)
Left/1.5 cm					0.599
Mean ± SD	2.44 ± 0.38	2.59 ± 0.42	2.59 ± 0.50	2.58 ± 0.43
95%CI	2.27-2.62	2.48-2.70	2.44-2.75	2.40-2.77
Left/2.0 cm					0.235
Mean ± SD	1.94 ± 0.29	2.01 ± 0.40	1.99 ± 0.27	2.06 ± 0.50
95%CI	1.82-2.06	1.92-2.11	1.91-2.06	1.93-2.19
Left/2.5 cm					0.363
Mean ± SD	1.72 ± 0.25	1.77 ± 0.29	1.73 ± 0.26	1.81 ± 0.31
95%CI	162-1.82	1.70-1.84	1.66-1.80	1.73-1.90
Left/3.0 cm					0.427
Mean ± SD	1.58 ± 0.19	1.69 ± 0.22	1.67 ± 0.26	1.64 ± 0.22
95%CI	1.48-1.68	1.62-1.75	1.58-1.75	1.58-1.70
Right/1.5 cm					0.218
Mean ± SD	2.48 ± 0.36	2.60 ± 0.41	2.43 ± 0.40	2.57 ± 0.39
95%CI	2.29-2.26	2.48-2.72	2.30-2.56	2.42-2.71
Right/2.0 cm					0.312
Mean ± SD	2.04 ± 0.26	2.11 ± 0.39	2.03 ± 0.27	2.18 ± 0.39
95%CI	1.93-2.16	2.02-2.21	1.96-2.10	2.08-2.28
Right/2.5 cm					0.064
Mean ± SD	1.65 ± 0.22	1.79 ± 0.29	1.69± 0.21	1.79 ± 0.34
95%CI	1.56-1.75	1.71-1.86	1.63-1.75	1.70-1.87
Right/3.0 cm					0.347
Mean ± SD	1.55 ± 0.26	1.65 ± 0.27	1.60 ± 0.19	1.65 ± 0.24
95%CI	1.38-1.71	1.58-1.77	1.52-1.67	1.58-1.72

BMI: Body mass index.

Table 5 Factors influencing the quality of the elastic image, n (%)

Factor	Image quality		P value	Image quality		P value
	Superior	Good		Superior	Good
Gender			0.875			0.423
Male	61 (70.9)	25 (29.1)		70 (81.4)	16 (18.6)
Female	84 (72.4)	32 (27.6)		89 (76.7)	27 (23.3)
Age group (yr)			<0.001			<0.001
<2	24 (85.7)	4 (14.3)		25 (89.3)	3 (10.7)
3-6	58 (85.3)	10 (14.7)		57 (83.8)	11 (16.2)
7-10	41 (70.7)	17 (29.3)		44 (75.9)	14 (24.1)
>10	22 (45.8)	26 (54.2)		27 (56.3)	21 (43.8)
BMI group (kg/m2)			<0.001			0.075
<15	21 (91.3)	2 (8.7)		17 (73.9)	6 (26.1)
15-16	60 (92.3)	5 (7.7)		56 (86.2)	9 (13.8)
16-17	34 (63.0)	20 (37.0)		45 (83.3)	9 (16.7)
>17	30 (50.0)	30 (50.0)		41 (68.3)	19 (31.7)

BMI: Body mass index; LL: Left lobe; RL: Right lobe. Significant differences are highlighted in boldface.