Magnetic Resonance Insights   

A. Huda^{1, 2}, R.K. Gupta³, N.Rajakumar² and M.A. Thomas²

¹Department of Physics, California State University, Fresno, CA 93740. ²Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA 90095. ³Department of Radiology, Sanjay Gandhi Post-Graduate Institute of Medical Sciences, Lucknow, India

Abstract

A spectrum of neuropsychiatric abnormalities caused by portosystemic venous shunting occurs in hepatic encephalopathy (HE) patients with or without liver dysfunction. It is not completely clear how the astrocyte swelling leads to glial-neuronal dysfunction, and how the symptoms are manifested in HE. A major goal of this work is to review the current status of information available from the existing magnetic resonance (MR) modalities including MR imaging (MRI) and MR Spectroscopy (MRS) as well as other modalities in the understanding the pathogenesis of HE. First, we discuss briefly neuron-histopathology, neurotoxins, neuropsychological and neurophysiological tests. A short review on the progress with single-photon emission computed tomography (SPECT) and positron emission tomography (PET) is then presented. In the remaining part of the manuscript, the following topics pertinent to understanding the pathogenesis of HE are discussed: MRI, diffusion tensor imaging (DTI), one-dimensional MRS based single- and multi-voxel based spectroscopic imaging techniques and two-dimensional MRS.