This article describes a basic 1.5-T hepatic magnetic resonance (MR) imaging protocol, strategies for optimizing pulse sequences while managing artifacts, the proper timing of postgadolinium 3-dimensional gradient echo sequences, and an effective order of performing pulse sequences with the goal of creating an efficient and high-quality hepatic MR imaging examination. The authors have implemented this general approach on General Electric, Philips, and Siemens clinical scanners.

Keywords

Hepatic MRI protocol

Hepatic MRI sequence optimization

Minimizing hepatic MRI artifacts

Extracellular space contrast agents

Hepatocyte-specific contrast agents

Postgadolinium pulse sequences

Diffusion-weighted imaging

Parallel imaging techniques

Key points

Introduction

Compared with other hepatic imaging modalities including ultrasonography, contrast-enhanced ultrasonography, computed tomography (CT), and positron emission tomography-CT, magnetic resonance imaging (MRI) offers more comprehensive evaluation of the liver, establishing in many cases an accurate tissue diagnosis. To fully harness the power of MRI, the techniques must be optimized while minimizing artifacts interfering with interpretation. The foundation for hepatic MRI includes T1-weighted images (including chemical shift imaging), T2-weighted images, fat suppression, and in most cases, contrast-enhanced images. Complementary imaging sequences include balanced steady state free precession (BSSFP) and diffusion weighted imaging (DWI). Pregadolinium and postgadolinium fat-suppressed T1-weighted 3D gradient echo (GRE) sequences are generally the workhorse of the examination and must be properly timed to account for the type of gadolinium based contrast agent (GBCA) while adjusting imaging parameters to maximize image quality. Finally, certain pulse sequences can be performed after gadolinium administration to improve examination efficiency while maximizing the diversity of pulse sequences.

This article describes a basic 1.5-T hepatic MRI protocol, strategies for optimizing pulse sequences while managing artifacts, the proper timing of postgadolinium 3D GRE sequences, and an effective order of performing pulse sequences with the goal of creating an efficient and high-quality hepatic MRI examination. The authors have implemented this general approach on Philips (Philips Medical Systems, Best, Netherlands), Siemens (Siemens Medical Solutions, Erlangen, Germany) and General Electric (GE Medical Systems, Milwaukee, Wisconsin, USA) clinical scanners.

The basic hepatic MR imaging examination

In clinical practice, the typical hepatic MR imaging examination (Table 1) includes comprehensive imaging of other abdominal viscera, although generally, the MR imaging protocol is optimized for evaluation of the liver. For gadolinium-enhanced studies, intravenous gadolinium should be administered as early as possible during the examination. Then, if the examination is prematurely terminated for any reason, gadolinium-enhanced images, which are often the most important sequences for lesion characterization, will have already been completed. This protocol is achievable because most sequences, except dual GRE (in and out of phase) sequences, single shot fast spin echo (SSFSE) heavily T2-weighted sequences, high-resolution 3D MR cholangiopancreatography (MRCP) sequences obtained after gadoxetate disodium administration, and short TI inversion recovery (STIR) sequences obtained after administration of extracellular space contrast agents (ECSAs), are not adversely affected by gadolinium and can be performed after gadolinium administration. A torso phased array coil should be used for all sequences, including localizer images.