Correlation of Ultrasound Based Measurements of Liver Stiffness and Steatosis With MRI

Study Overview
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Brief Summary
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The investigators will assess the ability of ultrasound (US) to measure liver stiffness (cirrhosis) and liver fat content (steatosis).

Detailed Description
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Non-invasive monitoring of liver fibrosis using magnetic resonance imaging (MRI) can help determine which patients will most benefit from interventional therapies to help reverse the condition. Similarly, quantitative assessment of liver fat content using MRI can assist physicians in identifying patients at risk for hepatic steatohepatitis. Due to the widespread dissemination of US machines and their relative lower cost compared to other imaging modalities, e.g. MRI, the ability of US to assess these parameters widens diagnostic availability. Patients who have undergone an MRI exam to assess liver stiffness (cirrhosis) and/or liver fat content (steatosis) will be asked to undergo an US exam to assess the same parameters. The cirrhosis and steatosis measurements obtained from both exams will be compared. If US-based measurements of liver stiffness and/or liver fat content are shown to be reproducible and accurate when compared to MRI values (will be used as the gold standard), US may become the first-line diagnostic test for these liver conditions.

Official Title
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Correlation of Ultrasound Based Measurements of Liver Stiffness and Steatosis With MRI

Conditions
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Liver Steatoses, Liver Cirrhosis

Intervention / Treatment
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* Diagnostic Test: Ultrasound


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: participants who have a clinical indication for a standard of care MRI exam that included assessment of the liver participant is at least 18 years of age Exclusion Criteria: Participants unable to take part in the decision making process on whether to consent to the trial Patients with previous chemoembolization or other focal liver therapies to the liver (* NOTE: for liver transplant patients, this criterion is only applicable to the transplanted liver)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients with Liver Fibrosis Measurement<br>Group1: Patients will undergo an Ultrasound to correlate fibrosis measurements obtained using standard-of-care MRI. | Diagnostic Test: Ultrasound<br>* Patients will undergo a standard liver US protocol for approximately 15 minutes.<br>* Other names: US fat quantification;|
| Patients with Liver Steatosis Measurement<br>Group 2: Patients will undergo an Ultrasound to correlate steatosis measurements obtained using standard-of-care MRI. | Diagnostic Test: Ultrasound<br>* Patients will undergo a standard liver US protocol for approximately 15 minutes.<br>* Other names: US fat quantification;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Discriminatory value (AUC) of US in assessing liver stiffness | 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. | an estimated time of 30 minutes | 
| Discriminatory value (AUC) of US in assessing liver fat content | 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. | an estimated average of 30 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| US Elastography Stiffness | 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. | an estimated average of 30 minutes |