Quantitative MRI of the liver: Evaluation of extracellular volume fraction and other quantitative parameters in comparison to MR elastography for the assessment of hepatopathy

Highlights

• ECV and T1 mapping correlate strongly with magnetic resonance elastography.

• ECV correlates stronger with serum markers of hepatopathy than MRE and T1 mapping.

• ECV is a promising tool for non-invasive assessment of liver fibrosis and cirrhosis.

Abstract

Background

Chronic liver diseases pose a major health problem worldwide, while common tests for diagnosis and monitoring of diffuse hepatopathy have considerable limitations. Preliminary data on the quantification of hepatic extracellular volume fraction (ECV) with magnetic resonance imaging (MRI) for non-invasive assessment of liver fibrosis are encouraging, with ECV having the potential to overcome several of these constraints.

Purpose

To clinically evaluate ECV provided by quantitative MRI for assessing the severity of liver disease.

Materials and methods

In this prospective study, multiparametric liver MRI, including T1 mapping and magnetic resonance elastography (MRE), was performed in subjects with and without hepatopathy between November 2018 and October 2019. T1, T2, T2*, proton density fat fraction and stiffness were extracted from parametric maps by regions of interest and ECV was calculated from T1 relaxometries. Serum markers of liver disease were obtained by clinical database research. For correlation analysis, Spearman rank correlation was used. ROC analysis of serum markers and quantitative MRI data for discrimination of liver cirrhosis was performed with MRE as reference standard.

Results

109 participants were enrolled (50.7 ± 16.1 years, 61 men). ECV, T1 and MRE correlated significantly with almost all serum markers of liver disease, with ECV showing the strongest associations (up to r = 0.67 with MELD, p < 0.01). ECV and T1 correlated with MRE (0.75 and 0.73, p < 0.01 each). ECV (AUC 0.89, cutoff 32.2%, sensitivity 85%, specificity 87%) and T1 mapping (AUC 0.85, cutoff 592.5 ms, sensitivity 83%, specificity 75%) featured good performances in detection of liver cirrhosis with only ECV performing significantly superior to model of end stage liver disease (MELD), AST/ALT ratio and international normalized ratio (p < 0.01, respectively).

Conclusion

Quantification of hepatic extracellular volume fraction with MRI is suitable for estimating the severity of liver disease when using MRE as the standard of reference. It represents a promising tool for non-invasive assessment of liver fibrosis and cirrhosis.

Introduction

Liver cirrhosis as the irreversible end stage of chronic liver injury from various etiologies poses a worldwide significant health problem due to an increasing incidence accompanied by high morbidity and mortality [1,2]. It carries the risk of portal hypertension, carcinogenesis and liver failure, and the only curative therapeutic approach is orthotopic liver transplantation. Therefore, an early diagnosis of potentially reversible stages of diffuse liver diseases, e.g., mild or moderate fibrosis, and the ability to monitor treatment response is desirable [3]. However, the gold standard for detection and staging of liver fibrosis remains liver biopsy, suffering from sampling error and periprocedural, potentially life-threatening risks due to its invasive nature [4,5]. As the most accurate non-invasive tests to date for the evaluation of liver fibrosis, elastography techniques using ultrasound (USE) and more recently magnetic resonance (MRE) have increasingly gained attention [6]. Since these methods still have several limitations and are not widely available, there is still a need for diagnostic tools allowing for a reliable assessment of liver fibrosis. Quantitative magnetic resonance imaging (MRI) techniques, such as T1 mapping and computation of extracellular volume fraction (ECV), have shown promising results in grading fibrotic change in other body regions, such as the heart [7,8] and the kidneys [9,10]; however, due to limited data [[11], [12], [13]], the diagnostic value of ECV calculation for assessment of liver fibrosis, especially in clinical routine, still remains undefined. Thus, the purpose of this study was to evaluate the diagnostic potential of ECV for assessing the severity of liver disease and detection of cirrhosis in patients with hepatopathy in comparison to other quantitative MR measures and serological surrogate markers of liver disease.