The purpose of this study is to prospectively compare the physiologic response of patients who receive either intravenous gadoxetic acid (Eovist) or intravenous gadobenate dimeglumine (MultiHance).

Contrast-enhanced hepatic MRI is an accepted method for detecting and characterizing liver lesions. Liver lesion characterization is fundamental for patient management, because lesions that meet specific imaging criteria for hepatocellular carcinoma (HCC) are assumed to be HCC without tissue confirmation. There are a variety of gadolinium-based contrast agents that are used for this purpose. Two of the more commonly utilized are gadoxetic acid (an hepatobiliary contrast agent that permits 20 minute hepatobiliary phase imaging) and gadobenate dimeglumine (a weak hepatobiliary contrast agent that functions generally as an extracellular contrast agent). A recent study by our group has shown that patients who receive intravenous gadoxetic acid are much more likely to experience transient dyspnea after contrast injection that causes them to breathe rapidly through the arterial phase of imaging, degrading image quality. In that study, subjective complaints of dyspnea and respiratory motion artifact on imaging were scored. The investigators did not assess patient physiologic response. The goal of the proposed work is to build on our prior data and to determine whether there are non-invasively measurable physiologic parameters that can support our original study. Specifically, the investigators want to determine whether there are predictable changes in SpO2, pulse, respiratory periodicity, and respiratory regularity that correlate with arterial phase image degradation and patients complains of dyspnea. Both contrast agents to be assessed in this study are FDA approved with at least 4 years of post-marketing experience documenting safety and efficacy. The investigators will not be changing or altering our clinical approach in any way as a part of this study.

Inclusion Criteria:

• Patients 18 years old and older
• Patients scheduled for MRI examination at the University of Michigan hospital
• Patients receiving either MultiHance or Eovist contrast agents during their clinical MRI examination

Exclusion Criteria:

• Patients under 18 years of age
• Patients who will not receive MultiHance or Eovist as part of their clinical MRI examination

One-hundred patients receiving gadoxetic acid for hepatobiliary indications and 100 patients receiving gadobenate dimeglumine for hepatobiliary indications will be studied prospectively. All patients will be scheduled to undergo MRI for clinical purposes by their primary care physicians. The patients will not be randomized.