Acceleration of chemical shift encoding-based water fat MRI for liver proton density fat fraction and T2* mapping using compressed sensing.

Fabian K Lohöfer,Dimitrios Karampinos,Andreas Hock,Rickmer F Braren,Christoph Katemann,Georgios A Kaissis,Ernst J Rummeny,Johannes M Peeters,Christina Müller-Leisse,Daniela Franz,Xi Chen

doi:10.1371/journal.pone.0224988

Abstract

ObjectivesTo evaluate proton density fat fraction (PDFF) and T2* measurements of the liver with combined parallel imaging (sensitivity encoding, SENSE) and compressed sensing (CS) accelerated chemical shift encoding-based water-fat separation.MethodsSix-echo Dixon imaging was performed in the liver of 89 subjects. The first acquisition variant used acceleration based on SENSE with a total acceleration factor equal to 2.64 (acquisition labeled as SENSE). The second acquisition variant used acceleration based on a combination of CS with SENSE with a total acceleration factor equal to 4 (acquisition labeled as CS+SENSE). Acquisition times were compared between acquisitions and proton density fat fraction (PDFF) and T2*-values were measured and compared separately for each liver segment.ResultsTotal scan duration was 14.5 sec for the SENSE accelerated image acquisition and 9.3 sec for the CS+SENSE accelerated image acquisition. PDFF and T2* values did not differ significantly between the two acquisitions (paired Mann-Whitney and paired t-test P>0.05 in all cases). CS+SENSE accelerated acquisition showed reduced motion artifacts (1.1%) compared to SENSE acquisition (12.3%).ConclusionCS+SENSE accelerates liver PDFF and T2*mapping while retaining the same quantitative values as an acquisition using only SENSE and reduces motion artifacts.

Highlights

The non-invasive quantification of fat and iron content in liver tissue is of high clinical significance
In patients with Non-Alcoholic Fatty Liver Disease (NAFLD), liver damage results in hyperferritinemia and hepatic iron accumulation [3, 4]. Both hepatic iron overload and steatosis can result in fibrosis, progress to cirrhosis and carry an increased risk for the development of hepatocellular carcinoma [5]
The first acquisition variant used acceleration based on SENSE with a total acceleration factor equal to 2.64

Summary

Introduction

The non-invasive quantification of fat and iron content in liver tissue is of high clinical significance. In patients with NAFLD, liver damage results in hyperferritinemia and hepatic iron accumulation [3, 4] Both hepatic iron overload and steatosis can result in fibrosis, progress to cirrhosis and carry an increased risk for the development of hepatocellular carcinoma [5]. Liver PDFF has emerged as a method for quantification of intrahepatic fat [13,14,15,16,17] with high sensitivity and specificity of 95.0% and 100.0% for the detection of histologic steatosis [13]. Chemical shift encoding-based water-fat separation by multi-echo gradient echo acquisition enables the simultaneous accurate and precise quantification of liver PDFF and T2

Objectives

Methods

Conclusion