Noninvasive investigations for non alcoholic fatty liver disease and liver fibrosis

Table 1 Clinical features of nonalcoholic fatty liver disease

Symptoms	Signs
None	Hepatomegaly (50% of patients)
Fatigue	Obesity
Right upper quadrant discomfort	Hypertension

Table 2 Noninvasive diagnosis of non-alcoholic fatty liver disease (adapted from Lewis et al[45]) (%)

Imaging	Sensitivity	Specificity	PPV	NPV
Ultrasound	91-100	93-100	62-89	94
Ultrasound (levovist)	100	95-100	N/A	N/A
Ultrasound (elasticity)	91	84	47	97
CT	93	N/A	76	N/A
MRI	N/A	N/A	N/A	N/A
MR (spectroscopy)	N/A	N/A	N/A	N/A
MR (elastography)	85	86	73	94

N/A: Not available; PPV: Positive predictive value; NPV: Negative predictive value; MRI: Magnetic resonance imaging; MR: Magnetic resonance; CT: Computed tomography.

Table 3 Serological markers for nonalcoholic steatohepatitis and fibrosis

Serological markers	Advantage	Disadvantage
C reactive protein[53]	Independent risk factor for progression of NAFLD	Lack of specificity for NASH
Plasma pentraxin 3[54]	Can differentiate between NASH and non progressive NAFLD	Lack of specificity for NASH
	Fibrosis marker in NAFLD
Hyaluronic acid[34]	Identify fibrosis at a cut-off value of 45 ng/mL	Cannot differentiate NASH from simple steatosis
Tissue inhibitor of metalloproteinases[34]	Fibrosis marker	Cannot differentiate NASH from simple steatosis
Cytokeratin 18[3]	Marker of hepatocyte apoptosis	Limited utility in clinical practice
	Independent predictor of NASH and severity of disease
Polypeptide specific antigen[57]	Marker in differentiating NASH from pure fatty liver	Marker for various cancers
Endothelin 1[59]	Can differentiate NASH from simple steatosis	Lack of specificity for NASH

NAFLD: Non-alcoholic fatty liver disease; NASH: Nonalcoholic steatohepatitis.