Thermoacoustic Method for Estimating Liver Fat Fraction

Inclusion Criteria: * Study participants are 18 or older. * Able to understand, read, and provide written informed consent in English. * Able to tolerate both ultrasound and MRI examinations. * Able to lie flat, or on their side, for 20 minutes and pause breathing for up to 10 seconds. Exclusion Criteria: * Metal or electronic implants, including, but not limited to: pacemakers, metal clips, drug delivery pumps, hip implants, and neural stimulation devices, contraindicates for MRI. * Known pregnancy the day of consent or becoming pregnant during study participation based on start date of last menstrual period). * Liver diseases other than MASLD/MASH/fibrosis including, but not limited to: * Cirrhosis * Hepatocellular carcinoma * Ascites * Patients with broken, or injured skin, in the right upper abdominal quadrant. * Body habitus, or anatomical variation, where the liver capsule is not accessible with ultrasound through the patient's right intercostal imaging window used in conventional ultrasound liver imaging. * BMI greater than 50 kg/m2 * Patients with subcutaneous fat at measurement location less than or equal to 6mm. * Patients with a missing liver lobe. * Patients with peri-hepatic fat in the measurement location. * Patients with focal liver lesions or anatomical structures in the measurement location, as detected by ultrasound.