Review
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World J Gastroenterol. Aug 28, 2014; 20(32): 11262-11272
Published online Aug 28, 2014. doi: 10.3748/wjg.v20.i32.11262
Multimodality magnetic resonance imaging in hepatic encephalopathy: An update
Xiao-Dong Zhang, Long-Jiang Zhang, Sheng-Yong Wu, Guang-Ming Lu
Xiao-Dong Zhang, Department of Medical Imaging, Jinling Hospital, Nanjing Clinical School, Southern Medical University, Nanjing 210002, Jiangsu Province, China
Xiao-Dong Zhang, Long-Jiang Zhang, Guang-Ming Lu, Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, Jiangsu Province, China
Sheng-Yong Wu, Department of Radiology, Medical Imaging Institute of Tianjin, Tianjin 300192, China
Author contributions: All authors contributed equally to this work; Zhang LJ and Lu GM designed the research; Zhang XD, Zhang LJ, Wu SY and Lu GM wrote the paper.
Supported by Grants from National Natural Science Foundation of China, Nos. 30700194, 81171313, 81322020 and 81230032 (to Zhang LJ); and Program for New Century Excellent Talents in University, No. NCET-12-0260 (to Zhang LJ)
Correspondence to: Long-Jiang Zhang, Associate Professor, Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, No. 305 Zhongshan East Road, Nanjing 210002, Jiangsu Province, China. kevinzhlj@163.com
Telephone: +86-25-80860185 Fax: +86-25-80860185
Received: October 26, 2013
Revised: January 29, 2014
Accepted: May 28, 2014
Published online: August 28, 2014
Abstract

Hepatic encephalopathy (HE) is a neuropsychiatric complication of cirrhosis or acute liver failure. Currently, HE is regarded as a continuous cognitive impairment ranging from the mildest stage, minimal HE to overt HE. Hyperammonaemia and neuroinflammation are two main underlying factors which contribute to the neurological alterations in HE. Both structural and functional impairments are found in the white mater and grey mater involved in HE. Although the investigations into HE pathophysiological mechanism are enormous, the exact pathophysiological causes underlying HE remain controversial. Multimodality magnetic resonance imaging (MRI) plays an important role in helping to understand the pathological process of HE. This paper reviews the up-to-date multimodality MRI methods and predominant findings in HE patients with a highlight of the increasingly important role of blood oxygen level dependent functional MRI.

Keywords: Hepatic encephalopathy, Magnetic resonance imaging, Magnetic resonance spectroscopy, Diffusion weighted imaging, Default-mode network, Blood oxygenation level dependent functional magnetic resonance imaging

Core tip: Multimodality magnetic resonance (MR) imaging is an effective and feasible research tool to uncover the pathophysiological mechanism of hepatic encephalopathy (HE). Among these MR imaging techniques, functional MR imaging method can be the most promising tool for studying HE. Nevertheless, the combination of functional MR imaging and other advanced MR techniques can be helpful to understand HE in the future.