Published online Jan 7, 2016. doi: 10.3748/wjg.v22.i1.89
Peer-review started: June 3, 2015
First decision: July 14, 2015
Revised: August 8, 2015
Accepted: October 13, 2015
Article in press: October 13, 2015
Published online: January 7, 2016
Since its introduction in the 1970’s, magnetic resonance imaging (MRI) has become a standard imaging modality. With its broad and standardized application, it is firmly established in the clinical routine and an essential element in cardiovascular and abdominal imaging. In addition to sonography and computer tomography, MRI is a valuable tool for diagnosing cardiovascular and abdominal diseases, for determining disease severity, and for assessing therapeutic success. MRI techniques have improved over the last few decades, revealing not just morphologic information, but functional information about perfusion, diffusion and hemodynamics as well. Four-dimensional (4D) flow MRI, a time-resolved phase contrast-MRI with three-dimensional (3D) anatomic coverage and velocity encoding along all three flow directions has been used to comprehensively assess complex cardiovascular hemodynamics in multiple regions of the body. The technique enables visualization of 3D blood flow patterns and retrospective quantification of blood flow parameters in a region of interest. Over the last few years, 4D flow MRI has been increasingly performed in the abdominal region. By applying different acceleration techniques, taking 4D flow MRI measurements has dropped to a reasonable scanning time of 8 to 12 min. These new developments have encouraged a growing number of patient studies in the literature validating the technique’s potential for enhanced evaluation of blood flow parameters within the liver’s complex vascular system. The purpose of this review article is to broaden our understanding of 4D flow MRI for the assessment of liver hemodynamics by providing insights into acquisition, data analysis, visualization and quantification. Furthermore, in this article we highlight its development, focussing on the clinical application of the technique.
Core tip: Liver cirrhosis is one of the leading cause of morbidity and mortality in the United States, Europe and Asia. Advanced stages of liver cirrhosis are accompanied by hemodynamic changes of the hepatic vascular system. Four-dimensional (4D) flow magnetic resonance imaging (MRI) has been validated for the clinical assessment of the liver blood flow in patients with advanced liver cirrhosis. It represents a method that supplements Doppler ultrasound and provides important additional information on the vessel system in difficult patients. The purpose of this review is to provide insights into 4D flow MRI for blood flow visualization and quantification in patients with advanced liver cirrhosis.