Eur Radiol (2009) 19: 2594–2607 DOI 10.1007/s00330-009-1470-y H E PATO B I L I A RY- PA N C R E A S Paul E. Sijens Parametric exploration of the liver by magnetic resonance methods Received: 4 February 2009 Revised: 24 April 2009 Accepted: 30 April 2009 Published online: 6 June 2009 # The Author(s) 2009. This article is published with open access at Springerlink.com P. E. Sijens (*) Radiology, University Medical Center Groningen and University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands e-mail: p.e.sijens@rad.umcg.nl Tel.: +31-50-3613534 Fax: +31-50-3611798 Abstract MRI, as a completely non- invasive technique, can provide quantitative assessment of perfusion, diffusion, viscoelasticity and metabo- lism, yielding diverse information about liver function. Furthermore, pathological accumulations of iron and lipids can be quantified. Perfusion MRI with various contrast agents is commonly used for the detection and characterization of focal liver disease and the quantification of blood flow parameters. An extended new application is the evaluation of the therapeutic effect of antiangiogenic drugs on liver tumours. Novel, but already widespread, is a histologically validated relaxometry method using five gradient echo sequences for quantifying liver iron content eleva- tion, a measure of inflammation, liver disease and cancer. Because of the high perfusion fraction in the liver, the apparent diffusion coefficients strongly depend on the gradient factors used in diffusion-weighted MRI. While complicating analysis, this offers the opportunity to study perfusion without contrast injection. Another novel method, MR elasto- graphy, has already been established as the only technique able to stage fibrosis or diagnose mild disease. Liver fat content is accurately determined with multivoxel MR spectroscopy (MRS) or by faster MRI methods that are, despite their widespread use, prone to systematic error. Focal liver disease characterisation will be of great benefit once multivoxel methods with fat suppression are implemented in proton MRS, in particular on high-field MR systems providing gains in signal- to-noise ratio and spectral resolution. Keywords Magnetic resonance imaging . Quantification . Liver Introduction Perfusion Although hepatic MR is now widely performed, it is still mainly used to detect focal lesions. However it is becoming much more widely appreciated that MR can provide a wide range of information about hepatic function and clinicians are beginning to request such investigations. Hence a review article is considered timely in order to familiarise more general radiologists about what MR can now offer. The liver is supplied with blood by the portal vein (75%) and by the hepatic artery (25%). Hepatic perfusion disorder refers to perfusion differences among segments, subseg- ments and lobes of the liver caused by various aetiologies, such as portal vein obstruction, liver cirrhosis, hepatic neoplasms, hepatic trauma, hereditary haemorrhagic telan- giectasia, hepatic vein obstruction, steal phenomenon by