MRI of the liver

Over the past few years, MRI of the liver has progressed significantly. MRI allows acquisition of images with excellent anatomical detail, high soft tissue contrast and largely free of artefacts secondary to respiratory motion. Fast sequences have reduced image acquisition time, thereby improving patient acceptance. New volumetric sequences have enabled three-dimensional serial dynamic imaging of the liver with high spatial and temporal resolution (Martin et al., 2005).

Unenhanced MR image (T1-weighted). Courtesy of Dr. Kühn, Germany

Unenhanced MR image (T2-weighted). Courtesy of Dr. Kühn, Germany

So called T1-weighted (scan-mode/water appears dark and fat bright) images allow thin-section imaging of the entire liver during a single suspended respiration. Volumetric three-dimensional sequencing enables improved detection, localization, and characterization of small lesions.

So called T2-weighted (scan-mode/water appears bright and fat grey) images are usually obtained through breathing-averaged or respiratory-triggered sequences with fat saturation (attenuation of the fat-signal). After the acquisition of unenhanced images, contrast-enhanced sequences are almost routinely obtained.

Benefits	Drawbacks
Highest diagnostic accuracy No radiation exposure Excellent multiplanar imaging possibilities Possibility to combine MR angiography/MR cholangiography sequences Contrast media with a favorable safety profile available Contrast media with a favorable safety profile available Initial Primovist® MRI scan can lead to changes in therapy management	More time consuming than CT Higher initial imaging cost in comparison to CT