Liver ultrasound scanning in the detection of hepatic steatosis and fibrosis in NASH patients

Abstract

Background

Nonalcoholic fatty liver disease (NAFLD) has become the most prevalent cause of liver disease in western countries. The development of nonalcoholic steatohepatitis (NASH) and fibrosis identifies the risk group with an increased incidence of liver-related deaths.

Aim

The aim of the present study is to investigate how accurately liver ultrasound (US) can contribute toward the prediction of the severity of liver damage in NAFLD, and to determine whether it may be an easily available, inexpensive, noninterventional, widely used screening method.

Methods

Fifty-four obese patients with variable degrees of BMI were recruited in the present study. Assessment of full medical history, anthropometric measurements, biochemical studies, abdominal US, liver biopsy for histological examination, and determination of the NAFLD activity score (NAS) score were carried out on all patients to identify NASH patients . Liver steatosis was evaluated using liver US, and graded according to a semiquantitative scale from 1 to 4. Liver histological examination was carried out to identify patients with NASH, borderline NASH, or non-NASH according to the NAS score.

Results

According to the NAS score, patients were divided into non-NASH patients (eight patients), borderline NASH patients (24 patients), NASH patients (20 patients), and patients with NASH and fibrosis (two patients). Alanine aminotransferase and γ-glutamyl transpeptidase were significantly higher in NASH patients. Correlating the grading of hepatic steatosis by liver US and NAS score, grade 1 was found in 37.5% of patients with non-NASH, 33.3% of patients with borderline NASH, and only in 5% of patients with NASH, whereas grade 4 steatosis was found in 20% of NASH patients and 4.2% of patients with borderline NASH; none of the non-NASH patients were diagnosed with grade 4 hepatic steatosis. The sensitivity of liver US in detecting grades of steatosis in liver biopsy was 61% in grade 1, 25% in grade 2, and 75% in grade 3. There was a direct correlation between grading of steatosis in the histological examination and the presence of NASH, P less than 0.000.

Conclusion

Liver US is not only sensitive in the detection of hepatic steatosis, but also in the prediction of the presence of NASH; therefore, it can be used as a simple, noninvasive, low-cost method for the screening of NAFLD and for the early identification of patients in need of aggressive intervention.