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Correlation between liver histology and novel magnetic resonance imaging in adult patients with non‐alcoholic fatty liver disease – MRI accurately quantifies hepatic steatosis in NAFLD

2012; Wiley; Volume: 36; Issue: 1 Linguagem: Inglês

10.1111/j.1365-2036.2012.05121.x

1365-2036

Zack Permutt, Tracy Le, Michael R. Peterson, Ekihiro Seki, David A. Brenner, Claude B. Sirlin, Rohit Loomba,

Liver Diseases and Immunity

Summary Background Conventional magnetic resonance imaging ( MRI ) techniques that measure hepatic steatosis are limited by T1 bias, T 2 * decay and multi‐frequency signal‐interference effects of protons in fat. Newer MR techniques such as the proton density‐fat fraction ( PDFF ) that correct for these factors have not been specifically compared to liver biopsy in adult patients with non‐alcoholic fatty liver disease ( NAFLD ). Aim To examine the association between MRI ‐determined PDFF and histology‐determined steatosis grade, and their association with fibrosis. Methods A total of 51 adult patients with biopsy‐confirmed NAFLD underwent metabolic‐biochemical profiling, MRI ‐determined PDFF measurement of hepatic steatosis and liver biopsy assessment according to NASH ‐ CRN histological scoring system. Results The average MRI ‐determined PDFF increased significantly with increasing histology‐determined steatosis grade: 8.9% at grade‐1, 16.3% at grade‐2, and 25.0% at grade‐3 with P ≤ 0.0001 (correlation: r 2 = 0.56, P < 0.0001). Patients with stage‐4 fibrosis, when compared with patients with stage 0–3 fibrosis, had significantly lower hepatic steatosis by both MRI ‐determined PDFF (7.6% vs. 17.8%, P < 0.005) and histology‐determined steatosis grade (1.4 vs. 2.2, P < 0.05). NAFLD patients with grade 1 steatosis were more likely to have characteristics of advanced liver disease including higher average AST : ALT (0.87 vs. 0.60, P < 0.02), GGT (140 vs. 67, P < 0.01), and INR (1.06 vs. 0.99, P < 0.01), higher stage of fibrosis and hepatocellular ballooning. Conclusions MRI ‐determined proton density‐fat fraction correlates with histology‐determined steatosis grade in adults with NAFLD . Steatosis is non‐linearly related to fibrosis progression. In patients with NAFLD , a low amount of hepatic steatosis on imaging does not necessarily indicate mild disease.