Noninvasive Pressure Estimation for Portal Hypertension

Inclusion Criteria: All subjects accepted for this trial must fulfill all the following criteria: * Be at least 18 years of age. * Be medically stable. * If a female of child-bearing potential, must have a negative pregnancy test. * Be conscious and able to comply with study procedures. * Have read and signed the IRB-approved Informed Consent form for participating in the study. Also there are specific inclusion criteria for each cohort: Cohort 1: • Be scheduled for transjugular liver biopsy where HVPG measurements will be obtained Cohort 2: • Have clinically significant portal hypertension undergoing routine HCC surveillance Cohort 3: • Have a diagnosis of portal hypertension and starting treatment with non-selective β-blockers Cohort 4: • Have clinically significant portal hypertension and be scheduled for endoscopy to screen for varices Exclusion Criteria: * Females who are pregnant or nursing. * Patients with pulmonary hypertension or unstable cardiopulmonary conditions * Patients currently on chemotherapy or with other primary cancers requiring systemic or hepatic loco-regional treatment. * Patients who are medically unstable, patients who are seriously or terminally ill, and patients whose clinical course is unpredictable. For example: * Patients on life support or in a critical care unit. * Patients with unstable occlusive disease (e.g., crescendo angina) * Patients with clinically unstable cardiac arrhythmias, such as recurrent ventricular tachycardia. * Patients with uncontrolled congestive heart failure (NYHA Class IV) * Patients with recent cerebral hemorrhage. * Patients who have undergone surgery within 24 hours prior to the study sonographic examination. * Patients with a history of anaphylactic allergy to eggs or egg products, manifested by one or more of the following symptoms: generalized urticaria, difficulty in breathing, swelling of the mouth and throat, hypotension, or shock. (Subjects with nonanaphylactic allergies to eggs or egg products may be enrolled in the study, but must be watched carefully for 1 hour following the administration of Sonazoid). * Patients with congenital heart defects. * Patients with severe emphysema, pulmonary vasculitis, or a history of pulmonary emboli. * Patients with respiratory distress syndrome * Patients with thrombosis within the hepatic, portal, or mesenteric veins. * Patients with grade 2 and above of hepatic encephalopathy within the last 3 months Also there is one additional exclusion criteria for cohort 1: • Patients with a history of anaphylactic allergy to perflutren (PEG) or any other components of Definity