The Role of Non-Gaussian Models of Diffusion Weighted MRI in Hepatocellular Carcinoma: A Systematic Review.

Liberatore Tramontano,Carlo Cavaliere,Marco Salvatore,Valentina Brancato

doi:10.3390/jcm10122641

Abstract

The importance of Diffusion Weighted Imaging (DWI) in hepatocellular carcinoma (HCC) has been widely handled in the literature. Due to the mono-exponential model limitations, several studies recently investigated the role of non-Gaussian DWI models in HCC. However, their results are variable and inconsistent. Therefore, the aim of this systematic review is to summarize current knowledge on non-Gaussian DWI techniques in HCC. A systematic search of the literature, including PubMed, Google Scholar, MEDLINE, and ScienceDirect databases, was performed to identify original articles since 2010 that evaluated the role of non-Gaussian DWI models for HCC diagnosis, grading, response to treatment, and prognosis. Studies were grouped and summarized according to the non-Gaussian DWI models investigated. We focused on the most used non-Gaussian DWI models (Intravoxel Incoherent Motion (IVIM), Diffusion Kurtosis Imaging (DKI), and Stretched Exponential—SE). The quality of included studies was evaluated by using QUADAS-2 and QUIPS tools. Forty-three articles were included, with IVIM and DKI being the most investigated models. Although the role of non-Gaussian DWI models in clinical settings has not fully been established, our findings showed that their parameters may potentially play a role in HCC. Further studies are required to identify a standardized DWI acquisition protocol for HCC diagnosis, grading, response to treatment, and prognosis.

Highlights

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer in the world and is one of the leading causes of cancer-related mortality worldwide [1]
Imaging plays a key role in HCC and all major clinical practice guidelines recommend the use of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) as the firstline modalities for diagnosis and staging of HCC [5]
Depending on how the motility of water molecules is limited by the tissue structure, the diffusion weighted imaging (DWI) signal intensity varies, and this may give information that is functional to HCC diagnosis, grading, response to treatment, and prognosis [10]

Summary

Introduction

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer in the world and is one of the leading causes of cancer-related mortality worldwide [1]. HCC development is characterized by extremely heterogeneous pathogenic mechanisms, epidemiology, and underlying diseases from each etiology This makes HCC diagnosis difficult at an early stage, affecting the choice of an effective therapeutic approach [2,3,4]. Multiparametric MRI is an excellent non-invasive tool for HCC diagnosis, grading, response to treatment, and prognosis. This because it combines morphological MRI sequences (such as T1 and T2 weighted) with functional methods such as diffusion weighted imaging (DWI) and dynamic contrastenhanced imaging, with the latter involving the use of hepatobiliary contrast agents [5,6,7,8]. Depending on how the motility of water molecules is limited by the tissue structure, the DWI signal intensity varies, and this may give information that is functional to HCC diagnosis, grading, response to treatment, and prognosis [10]

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Conclusion