Tissue elasticity and viscosity correlate with pathology. These tissue properties are typically evaluated subjectively using palpation. The purpose of "elastography" is to provide an objective elasticity image that is equivalent to the remote palpation of tissue. The investigators have developed elastography imaging systems based on ultrasound and magnetic resonance imaging and have applied them previously to prostate imaging, breast imaging in patients and liver imaging in healthy volunteers.
A first objective of this study is to compare the investigators' ultrasound shear wave absolute vibro-elastography (S-WAVE) technology with the existing clinical standard, FibroScan, and magnetic resonance elastography to quantify liver stiffness in healthy volunteers and in patients suspected of fatty liver disease.
A second objective of this study is to compare ultrasound-based liver tissue fat measurement with MRI-based measurements.
A third objective of this study is to determine whether ultrasound can be used to assess liver inflammation.