Controversy in the diagnosis of pediatric non-alcoholic fatty liver disease

Table 1 Advantages and disadvantages of non-alcoholic fatty liver disease diagnostic techniques

Diagnostic techniques	Advantages	Disadvantages
Biopsy	Gold Standard, highest sensitivity and specificity	Invasive and expensive;
		Sampling error of liver biopsy can result in substantial misdiagnosis and staging inaccuracies;
ALT serum levels dosage	Widely available and inexpensive, useful as screening	Low sensitivity
Ultrasound	Widely available, inexpensive. When the percentage of steatosis is > 20%, sensitivity and specificity are acceptable. Useful as screening	Can not differentiate between steatosis and steatohepatitis;
		Can not establish with certainty the degree of fatty infiltration;
		Can not differentiate between steatosis and other diffuse liver diseases characterized by increased echogenicity;
		Can not always identify the spared or focal steatosis areas from hepatic focal lesions
Unenhanced computed tomography	Good sensitivity and specificity compared to live biopsy	Quantitative assessment of macrovesicular steatosis is not clinically acceptable;
		Radiations exposure
Magnetic resonance	Good sensitivity and specificity compared to live biopsy in adult population	There are insufficient data to make evidence-based recommendations regarding its use in children
	It is not invasive and it is not irradiating
1H-MR spectroscopy	It has been applied successfully in a pediatric pilot study to measure hepatic fat content in patients with histopathological evidence of NASH before and after pharmacological treatment	It is time-consuming and requires off-scan analysis by an expert
		Its use appear to be more appropriate for research studies and not suitable for widespread use
Transient elastography	Good correlation with hepatic histology both in adults and children	It is not yet performed in everyday clinical practice
Magnetic resonance elastography	It could be a complement to 1H-MR spectroscopy to estimate non-invasively the degree of steatosis and degree of liver stiffness	Further studies are needed before to validate this method
Biomarkers, prediction scores Equations and tests	Could help the clinicians to perform NAFLD diagnosis and evaluate progression to NASH without performing liver biopsy	There are contrasting results and more validation studies are needed

NAFLD: Non-alcoholic fatty liver disease; ALT: Alanine transaminase; NASH: Non-alcoholic steatohepatitis;

¹H-MR: ¹H-Magnetic resonance.