Limitations and opportunities of non-invasive liver stiffness measurement in children

Table 1 Comparison of the 4 main histological scoring systems used in the evaluation of fibrosis in paediatric liver diseases today

Scoring system	Staging	Evaluated in adults with	Evaluated in children with
METAVIR	F0-F4	Hepatitis B and C	Biliary atresia, intestinal failure, total parenteral nutrition and post-liver transplantation
Ishak	F0-F6	Hepatitis B and C	Post-liver transplantation and after cardiovascular surgery
Desmet	F0-F4	Hepatitis C	No
SSS-score	0- > 15	Hepatitis B and C	Hepatitis B

Table 2 Control and normal values of non-invasive liver stiffness measurement

	Normal values (ULN is defined as mean + 1.64 SD)
	Children	Adults	Impulse generation
TE	ULN: 6.47 kPa[40]	8.3/7.83 (m/f)[39]	Mechanical
RTE	Median: 106 a.u.[67]	127 a.u.[78]	Aortal pulsing
MRE	Mean: 2.71 kPa[79]	3.45 kPa[80]	Acoustic
	-2.93 kPa[71]
ARFI	ULN: 1.39 m/s (mean + 1.64 SD)[59,81]	1.35 m/s[36]	Ultrasound

Normal values are defined as mean + 1.64 times SD, while control values are expressed as mean. ARFI: Acoustic radiation force impulse; MRE: Magnetic resonance elastography; RTE: Real-time tissue elastography; TE: Transient elastography; ULN: Upper limit of normal.