Liver Fat, Iron, & Fibrosis Abbreviated Protocols
Sudhakar K Venkatesh1

1Radiology, Mayo Clinic, Rochester, MN, United States

Synopsis

With the emergence of non-alcoholic fatty liver disease (NAFLD) as most common chronic liver disease, detection and quantification of liver fat and fibrosis becomes important. Iron overload frequently seen in association with fatty liver and liver fibrosis. Noninvasive quantification of liver fat, iron and fibrosis with MRI is now considered the standard for diagnosis and monitoring. In this presentation, typical clinical scenarios that requires MRI abbreviated protocol for liver fat, iron and fibrosis quantification, candidate sequences and multi-parametric MRI protocols will be discussed. MRI protocols will be illustrated with clinical examples and limitations will be highlighted.

Outcome/Objectives

At the end of this lecture,the participant will be able to

  • Understand the clinical scenarios that require abbreviated protocol for hepatic fat, iron and fibrosis
  • Learn about multi-parametric MRI protocols
  • Understand the limitations of abbreviated protocol

Background

Non-alcoholic fatty liver disease is the leading cause of chronic liver disease (CLD), hepatocellular carcinoma and liver transplantation in the world. NAFLD has a spectrum of relatively benign non-progressive non-alcoholic fatty liver (NAFL) to progressive nonalcoholic steatohepatitis (NASH) which would finally lead to fibrosis or cirrhosis. Physicians evaluating the patients at risk of NAFLD (obesity, diabetes, and metabolic syndrome) would first confirm the diagnosis of NAFLD, then determine NASH vs. NAFL and finally assess the severity of hepatic fibrosis. Fibrosis is the most important prognostic factor in NAFLD patients and advanced fibrosis (≥ stage 3) carry worse prognosis. Increased iron deposition commonly occurs in many CLD including NAFLD. Quantifying Liver iron content (LIC) is important for confirmation of hereditary hemochromatosis (HH) in patients with genetic predisposition and for management decisions in known HH patients. LIC is also important in patients with iron overload due to transfusions or hematologic disorders for decisions on chelation therapy. Liver fibrosis is the end-stage healing response to injury in CLDs and the outcome depends on fibrosis stage. Early detection is of paramount importance as anti-fibrotic treatment would be most effective at earlier stages of liver fibrosis. Monitoring progression and response to anti-fibrotic treatment are invaluable in the follow up of CLD patients.

Typical clinical scenarios for abbreviated liver quantification protocol

  • Living liver transplant donor
  • Detection and quantification of fat, iron and fibrosis in patients with risk factors
  • Assessment of response to treatment or interventions
  • Clinical trials
  • Patient factors- mild claustrophobia, chronic disability, spine issues, etc

Ideal abbreviated Protocol

  • Reduced scan time (time is money!)- A breath hold sequence would be great
  • Simple to perform- set up, running the sequence, minimum post processing
  • Proven clinical utility and diagnostic accuracy
  • Low failure rate/recalls
  • No need for intravenous contrast


Candidate sequences for abbreviated protocol

Fat

  • Conventional In/Opp sequence; 2D or 3D dual echo
  • Chemical shift based Proton density fat fraction calculation (PDFF)

Iron

  • Signal intensity ratio
  • R2* Relaxometry

Fibrosis

  • MR Elastography
  • Liver T1-mapping
  • Diffusion weighted imaging and ADC

Multi-parametric protocol examples

  • Localizer + 2D/3D dual echo + MRE: liver fat detection and rule out steatohepatitis +/- fibrosis
  • Localizer + IDEAL + MRE: liver fat, iron and fibrosis quantification
  • Localizer + T1 map+ T2*+ PDFF: liver fat, iron and LIF marker quantification

Limitations

  • Potentially miss focal liver lesions such as HCC developing in background of liver fibrosis
  • Limited evaluation of portal hypertension features particularly esophageal varices that have potential to bleed with high mortality

Acknowledgements

No acknowledgement found.

References

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Figures

Abbreviated protocol for detection of fat and fibrosis

Abbreviated protocol for detection and quantification of liver fat, iron and fibrosis

Proc. Intl. Soc. Mag. Reson. Med. 26 (2018)