Noninvasive assessment of liver structural changes in case of diffuse liver diseases

Abstract

Background. The most important factors affecting the prognosis, tactics and results of the treatment of chronic diffuse liver diseases, comprising non-alcoholic fatty liver disease (NAFLD) and chronic hepatitis associated with virus C (HCV), include the progression rate of fibrotic liver transformation and the fibrous tissue area. The fibrosis extent is a predictor of portal hypertension and such lethal complications as bleeding from esophagus varicose veins, acute liver failure and hepatocellular carcinoma. Materials and methods. The investigation involved 66 patients with chronic diffuse liver diseases. All the patients were divided into two groups and three subgroups. Group I consisted of patients with HCV and cirrhosis associated with hepatitis C virus; group II included patients with NAFLD. Depending on the severity of fibrosis, patients in each group were subdivided into three subgroups: no fibrosis (F0), moderate fibrosis (FI + FII), and marked fibrosis (FIII + FIV). Viral etiology of the disease was confirmed by the enzyme immunoassay analysis and PCR diagnostics. Group I consisted of 24 (57.1 %) men and 18 (42.9 %) women; the average age of patients was (45.8 ± 2.2) years. The diagnosis of NAFLD was confirmed by the results of objective examination (the presence of overweight, visceral distribution of adipose tissue), detection of insulin resistance and hyperlipidemia. Group II consisted of 8 men (33.3 %), 16 women (66.7 %); the average age was (47.3 ± 3.1) years. In all the patients the diagnosis was morphologically confirmed. The ultrasound examination of the liver in B-mode was performed, as well as shear wave elastography (SWE). Results. In 13 (19.7 %) cases (7 patients with HCV and 6 patients with NAFLD), fibrous changes of the liver were absent. 43.9 % of patients (19 patients with HCV and 10 patients with NAFLD) were diagnosed with a moderate stage of liver fibrosis, which coincided with stages 1 and 2 of fibrosis on the METAVIR scale. In 36.4 % of cases (16 patients with HCV and 8 patients with NAFLD), the stage of marked liver fibrosis was diagnosed, which coincided with stages 3 and 4 of fibrosis on the METAVIR scale. According to the ROC analysis, the SWE threshold value above which a moderate stage of HCV liver fibrosis was diagnosed proved to be 6.63 kPa (with the sensitivity of 94.7 % and the specificity of 85.7 %). In the assessment of marked fibrosis it was more than 8.81 kPa (with sensitivity of 93.7 % and specificity of 84.2 %). For NAFLD, the threshold value for moderate fibrosis was 5.56 kPa (AUC = 0.867 (95% CI 0.606 to 0.982; p < 0.001)), for marked fibrosis — more than 7.87 kPa (with the sensitivity of 87.5 % and specificity of 90.0 %). Conclusions. According to SWE results, a moderate fibrosis in patients with HCV corresponded to the value of 6.63 kPa and to 5.56 kPa for NAFLD; a marked fibrosis was diagnosed at values higher than 8.81 and 7.87 kPa for HCV and NAFLD, respectively. The SWE method has high sensitivity and specificity for staging of liver fibrosis in patients with HCV and NAFLD and may be recommended for the use in clinical practice. Introduction of SWE with the defined threshold values for liver parenchyma stiffness allows optimizing noninvasive diagnosis of fibrotic liver changes in patients with HCV and NAFLD.

Keywords

• shear wave elastography
• liver fibrosis
• chronic diffuse liver diseases