Group1: Patients will undergo an Ultrasound to correlate fibrosis measurements obtained using standard-of-care MRI.

Group 2: Patients will undergo an Ultrasound to correlate steatosis measurements obtained using standard-of-care MRI.

Patients will undergo a standard liver US protocol for approximately 15 minutes.

Discriminatory value (the ability of the test to diagnose disease from healthy) will be calculated using nonparametric receiver operating characteristic (ROC) curve analysis. Sensitivity (i.e. true positive rate: the ability of a test to correctly identify patients with the disease being investigated) is plotted on the y axis and 1-specificity (i.e. false positive rate: the test incorrectly identifies patients who do not have the disease being investigated as having the disease) will be plotted on the x-axis. Cutoff points of US liver stiffness values will be chosen to create the graph of sensitivity versus 1-Specificity, i.e. the ROC curve, and the area under the curve (AUC) is used to determine how well US discriminates patients with liver stiffness from patients without liver stiffness.

The closer the AUC gets to 1, the more discriminatory the test. An AUC=0.5 is a test that is right 50% of the time, and is no better than flipping a coin.

Discriminatory value (the ability of the test to diagnose disease from healthy) will be calculated using nonparametric receiver operating characteristic (ROC) curve analysis. Sensitivity (i.e. true positive rate: the ability of a test to correctly identify patients with the disease being investigated) is plotted on the y axis and 1-specificity (i.e. false positive rate: the test incorrectly identifies patients who do not have the disease being investigated as having the disease) will be plotted on the x-axis. Cutoff points of US liver fat content values will be chosen to create the graph of sensitivity versus 1-specificity, i.e. the ROC curve, and the area under the curve (AUC) is used to determine how well US discriminates patients with liver fat content from patients without liver fat content.

The closer the AUC gets to 1, the more discriminatory the test. An AUC=0.5 is a test that is right 50% of the time, and is no better than flipping a coin.

MRI tissue stiffness is reported in shear modulus (S), while US uses Young's modulus (Y). Since Y = 2*(1+m)*S, where m is the Poisson's ratio for the material, and since that ratio is between 0.49 and 0.50 for tissue, the US measurements should be three times that of the MRI ones. In particular, treating the MRI measurements as the reference, theory predicts a linear relationship:

Y = 0 + 3*S

which can be tested with a linear regression model. The most straightforward means is by calculating the expected Young's modulus values for US from the MR measurements, and regressing them on the observed US measurements.

Both US and MRI values are given below.