MR Elastography Protocol

Information for Scheduling the Exam

  1. The patient should fast for a minimum of 4 hours before the exam

Information for MRI Technologists

Background

1.     Supine patient positioning

2.     Torso phased array coil

3.     Pneumatic passive driver for MR Elastography

Contrast Enhanced Liver MRI Protocol

1.     Pulse Sequences

a.      3-plane localizer sequence (SSFSE)

b.     Coronal SSFSE ASSET

c.      Axial SSFSE ASSET

d.     Liver fat and iron quantification

·  Must be performed pre-contrast

e.      Axial LAVAflex pre and dynamic post X2

·  See “Gadolinium Page” for choice of contrast agent

f.      Elastography

g.     Axial LAVAflex

h.     Diffusion (b=0, 20 and 800)

i.       Radial SSFSE MRCP

# Note: Do NOT perform 3D MRCP unless specifically requested

Non-Contrast Liver MRI Protocol

1.     Pulse Sequences

a.      3-plane localizer sequence (SSFSE)

b.     Coronal SSFSE ASSET

c.      Axial SSFSE ASSET

d.     Liver fat and iron quantification

e.      Elastography

f.      Axial LAVAflex pre

g.     Diffusion (b=0, 20 and 800)

h.     Radial SSFSE MRCP

# Note: Do NOT perform 3D MRCP unless specifically requested

MR Elastography Information

a.      Pneumatic passive driver

·  Place driver in the right lower chest/upper abdomen in the mid clavicular line so that the largest portion of the liver is directly under the driver

b.     Technique

·  The 2D-GRE MRE sequence is performed at 60 Hz, and four slices of 10-mm thickness are prescribed over the region of liver with the largest cross section. This is usually near the liver dome, but the dome should be avoided as there may be breath hold artifacts.

·  Slices should be obtained in expiration to ensure reproducibility of the position of the liver.

c.      Imaging Parameters

·  TR 50 ms; TE 20.2 ms (18.4 – 26 ms); flip angle 300; matrix, 256 x 64; FOV 48 x 48 cm; one-signal average; receiver bandwidth 633 kHz (confirm); and parallel imaging acceleration factor, 2.

·  Repeat 4 times adjusting the phase offset

·  Echo times can be adjusted if needed

1.     TE of 18.4 ms is in phase and can benefit patients with a fatty liver

2.     A TE below 20 ms may be useful in patients with liver iron overload.

·  Breath hold duration is about 16 – 20 seconds

 

References

1.     Loomba R, et al. Magnetic Resonance Elastography Predicts Advanced Fibrosis in Patients with Nonalcoholic Fatty Liver Disease: A Prospective Study. Hepatology Vol 60, No. 6, 2014.

2.     Venkatesh SK, Ehman RL. Magnetic resonance elastography of abdomen. Abdominal Imaging Dec 2014.

3.     Venkatesh SK, Yin M, Ehman RL. Magnetic Resonance Elastography of Liver: Technique, Analysis, and Clinical Applications. JMRI 37:544-555 (2013).

4.     Yin M, et al. A Preliminary Assessment of Hepatic Fibrosis with MR Elastography. Clin Gastroenterol Hepatol. 2007 October; 5 (10): 1207 1213.e2.

 

Rev: January 15, 2015