Multiparametric magnetic resonance imaging for the assessment of non-alcoholic fatty liver disease severity

Abstract

Background & aims: The diagnosis of non-alcoholic steatohepatitis and fibrosis staging are central to non-alcoholic fatty liver disease assessment. We evaluated multiparametric magnetic resonance in the assessment of non-alcoholic steatohepatitis and fibrosis using histology as standard in non-alcoholic fatty liver disease.

Methods: Seventy-one patients with suspected non-alcoholic fatty liver disease were recruited within 1 month of liver biopsy. Magnetic resonance data were used to define the liver inflammation and fibrosis score (LIF 0-4). Biopsies were assessed for steatosis, lobular inflammation, ballooning and fibrosis and classified as non-alcoholic steatohepatitis or simple steatosis, and mild or significant (Activity ≥2 and/or Fibrosis ≥2 as defined by the Fatty Liver Inhibition of Progression consortium) non-alcoholic fatty liver disease. Transient elastography was also performed.

Results: Magnetic resonance success rate was 95% vs 59% for transient elastography (P<.0001). Fibrosis stage on biopsy correlated with liver inflammation and fibrosis (r_s =.51, P<.0001). The area under the receiver operating curve using liver inflammation and fibrosis for the diagnosis of cirrhosis was 0.85. Liver inflammation and fibrosis score for ballooning grades 0, 1 and 2 was 1.2, 2.7 and 3.5 respectively (P<.05) with an area under the receiver operating characteristic curve of 0.83 for the diagnosis of ballooning. Patients with steatosis had lower liver inflammation and fibrosis (1.3) compared to patients with non-alcoholic steatohepatitis (3.0) (P<.0001); area under the receiver operating characteristic curve for the diagnosis of non-alcoholic steatohepatitis was 0.80. Liver inflammation and fibrosis scores for patients with mild and significant non-alcoholic fatty liver disease were 1.2 and 2.9 respectively (P<.0001). The area under the receiver operating characteristic curve of liver inflammation and fibrosis for the diagnosis of significant non-alcoholic fatty liver disease was 0.89.

Conclusions: Multiparametric magnetic resonance is a promising technique with good diagnostic accuracy for non-alcoholic fatty liver disease histological parameters, and can potentially identify patients with non-alcoholic steatohepatitis and cirrhosis.

Keywords: diagnostic accuracy; non-alcoholic steatohepatitis; non-invasive test; sensitivity and specificity.

Figure 1

Study flow chart. NAFLD, non‐alcoholic fatty liver disease, MR, magnetic resonance, TE, transient elastography

Figure 2

Representative magnetic resonance data. Magnetic resonance data (T₁, T₂*, cT ₁ maps and LIF scores) from patients classified using the Fatty Liver Inhibition of Progression (FLIP) algorithm as having: mild disease (top panel), significant disease/mild fibrosis (middle panel) and significant disease/advanced fibrosis (bottom panel). Red circles indicate typical regions of interest. Iron‐corrected T₁ (cT ₁), liver inflammation and fibrosis (LIF) scores, and corresponding transient elastography (TE) data and histological scores are included. The predefined colour scale for generating the LIF score is based on the cT ₁ maps and is shown in each case [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 3

Liver inflammation and fibrosis score for the evaluation of (A) fibrosis, (B) ballooning, (C) lobular inflammation and (D) activity. (A) There was a significant association between LIF and fibrosis (r _s=.51; P<.0001). The median LIF score could differentiate (B) ballooning grades (LIF 1.2, 2.7 and 3.5 for ballooning grades 0, 1 and 2 respectively (P<.05), (C) lobular inflammation grades (LIF 1.6 vs 2.7 for lobular inflammation grade 0 vs >0) and (D) overall activity (LIF 1.3 vs 3.0 for mild (0‐1) vs significant activity.2, 3, 4 Lines and error bars indicate the median and interquartile range on all graphs [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 4

Liver inflammation and fibrosis score for the assessment of the total steatosis, activity and fibrosis score. There was a strong association between the liver inflammation and fibrosis score (LIF) and the overall histological severity scored by the steatosis, activity and fibrosis score (SAF; r _s=.70; P<.0001) [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 5

Liver inflammation and fibrosis score for NAFLD classification according to the Fatty Liver Inhibition of Progression consortium algorithms. Liver inflammation and fibrosis scores (LIF) are plotted against the diagnostic categories of the Fatty Liver Inhibition of Progression (FLIP) algorithm. (A), Patients with steatosis had lower median LIF scores compared to patients with NASH (1.3 vs 3.0; P<.0001) and (B), patients with mild disease had lower median LIF scores compared to patients with severe disease (2.2 vs 3.3; P<.0001). Lines and error bars indicate the median and interquartile range on both graphs [Colour figure can be viewed at wileyonlinelibrary.com]