The investigators plan to investigate the use of US shear wave elastography (SWE), a newly available imaging technology, in children with suspected/known BA.

The investigators plan a prospective, multi-center study to determine if liver ultrasound shear wave speed measurements acquired at clinical presentation can discriminate biliary atresia (BA) from other causes of liver disease in the setting of neonatal cholestasis. The investigators also plan to determine if liver ultrasound shear wave speed measurements acquired at clinical presentation or longitudinally during the first one-year period after Kasai can predict important long-term outcomes in BA patients.

Inclusion Criteria:

• neonatal cholestasis with concern for BA vs. other liver disease direct bilirubin >20% of total or ≥2 mg/dL age <3 months

Exclusion Criteria:

• inability to obtain parent/guardian consent.
• inability to return for follow up visits as required by the study (these patients will be included in aim 1, but will be unable to participate in aim 2).
• no other exclusion criteria.

neonatal cholestasis with concern for BA vs. other liver disease direct bilirubin >20% of total or ≥2 mg/dL age <3 months