Clinical Application of Quantitative MR Imaging in Nonalcoholic Fatty Liver Disease

Abstract

Viral hepatitis was previously the most common cause of chronic liver disease. However, in recent years, nonalcoholic fatty liver disease (NAFLD) cases have been increasing, especially in developed countries. NAFLD is histologically characterized by fat, fibrosis, and inflammation in the liver, eventually leading to cirrhosis and hepatocellular carcinoma. Although biopsy is the gold standard for the assessment of the liver parenchyma, quantitative evaluation methods, such as ultrasound, CT, and MRI, have been reported to have good diagnostic performances. The quantification of liver fat, fibrosis, and inflammation is expected to be clinically useful in terms of the prognosis, early intervention, and treatment response for the management of NAFLD. The aim of this review was to discuss the basics and prospects of MRI-based tissue quantifications of the liver, mainly focusing on proton density fat fraction for the quantification of fat deposition, MR elastography for the quantification of fibrosis, and multifrequency MR elastography for the evaluation of inflammation.

Severe hepatic steatosis promotes increased liver stiffness in the early stages of metabolic dysfunction–associated steatotic liver disease

“…In addition, this accuracy was consistent across patient subgroups (obesity, sex) and disease states (inflammation grade, liver stiffness) 11 . Quantitative MRI can thus be expected to play a pivotal role in screening, diagnosis and treatment monitoring of MASLD by allowing comprehensive and noninvasive evaluation of pathological liver changes 12 …”

“…In the presence of inflammation and ballooning, the elastic modulus is high due to increased intra-tissue pressure caused by increased regional blood flow, congestive oedema, and inflammatory cell infiltration, and therefore, the interpretation of LSM changes must account for these effects. 12 Inflammation and ballooning are known factors associated with fibrosis progression. 29 As such, we cannot rule out the possibility that this study evaluated these influences together.…”

“…In this study, progression of liver fibrosis was evaluated by changes in LSMs determined by MRE. In the presence of inflammation and ballooning, the elastic modulus is high due to increased intra‐tissue pressure caused by increased regional blood flow, congestive oedema, and inflammatory cell infiltration, and therefore, the interpretation of LSM changes must account for these effects 12 . Inflammation and ballooning are known factors associated with fibrosis progression 29 .…”

“…11 Quantitative MRI can thus be expected to play a pivotal role in screening, diagnosis and treatment monitoring of MASLD by allowing comprehensive and noninvasive evaluation of pathological liver changes. 12 Fibrosis stage strongly predicts outcomes in patients with NAFLD. 13 Therefore, patients at high risk of fibrosis progression should be targeted with lifestyle and pharmacological interventions.…”

Advanced fibrosis leads to overestimation of steatosis with quantitative ultrasound in individuals without hepatic steatosis

“…We only used MR elastography value as an indicator of liver fibrosis. In the presence of inflammation and ballooning, elastic modulus is high due to increased intra-tissue pressure caused by increased regional blood flow, congestive edema, and inflammatory cell infiltration; the interpretation of liver stiffness measurement changes must account for these effects [ 39 ]. Future studies with histological evaluation of fibrosis are necessary.…”