Evaluation of the Efficacy of Contrast Enhanced Ultrasound Compared to MRI for Differentiation of Hepatic Lesions

Hepatic imaging plays an important role in identifying and differentiating both benign and
malignant neoplasms of the liver. One of the clinical and radiologic dilemmas facing hepatic
medicine is the accurate differentiation of focal nodular hyperplasia (FNH) and hepatic
adenoma (HA). This is a question of some import, as there are significant prognosis and
treatment differences between these entities, as well as overlap in the patient populations
in whom they occur.

FNH is the second most common benign neoplasm of the liver, with a strong female
predilection. These lesions are usually asymptomatic and incidentally discovered, and carry
only a small risk of complication such as bleeding. There is no malignant potential. Hepatic
adenomas (HAs) are more rare benign neoplasms that also have a female predilection. However,
these lesions are more likely to be symptomatic, and carry a higher bleeding risk especially
as they grow over 4 cm. In addition, they harbor a small risk of malignant transformation to
hepatocellular carcinoma (HCC). Of note, patients may present with both types of lesion
concurrently.

Currently, MRI with hepatobiliary contrast agents is the standard for differentiation of
these lesions. These agents (such as gadoxetate disodium, or Eovist) are actively transported
into hepatocytes, which are present in FNH and only in very rare cases with HA. Previous
research (such as from Grazioli et al.) has shown that hepatobiliary agents can differentiate
these lesions with excellent accuracy. However, there is still overlap between these lesions
on imaging, and for certain patients MRI may be difficult or impossible.

FDA approval of contrast enhanced ultrasound (CEUS) agents in 2016 has opened a new avenue
for abdominal imaging. CEUS utilizes gas containing lipid microbubbles to provide pure
intravascular contrast, allowing for evaluation of vascular and solid organ perfusion. It has
an excellent safety profile and is not excreted by the kidneys, allowing for use in patients
with acute and chronic renal disease. It has been used for some time outside of the US for
liver lesion evaluation, and the enhancement patterns of both FNH and HA have been described
in the literature by Kim et al. as having different appearances. CEUS can be especially
useful for focal liver lesion imaging for patients who cannot or will not undergo MRI, and it
has the advantages of flexibility, increased temporal resolution, and decreased cost. This
study aims to compare the utility of CEUS for differentiating FNH and HA with the current
standard of hepatobiliary contrast MRI.

Inclusion Criteria:

1. Males and females

2. Age 18 years or greater

3. Scheduled to undergo abdominal MRI with contrast at a performance site for evaluation
of a hepatic lesion(s).

Exclusion criteria:

1. History of cardiac shunting

2. History of acute cardiac ischemia

3. History of hypersensitivity reaction to Lumason