- Patients with concurrent, confounding causes of liver dysfunction clinically evident or evident on ultrasound or other radiographic imaging (such as evidence of biliary ductal dilatation or focal tissue defects) may require biopsy-proven VOD and/or elevated wedged trans-hepatic venous pressure gradient measurement ( ≥10 mm mercury) to be considered eligible. Best medical judgment and further imaging studies can be used to clarify the diagnosis and determine confounding causes of liver dysfunction.