@gerhardt26, Welcome to Connect. I have located this link to this research study. It looks like it is currently accepting participants at Mayo Arizona. Here is a link for more information:
Pilot Study to Assess the Validity of "Liquid Biopsy" to Improve Diagnosis, Prognostic Assessment and Disease Monitoring in Patients Undergoing Liver Transplant for Hilar and Intrahepatic Cholangiocarcinoma
https://www.mayo.edu/research/clinical-trials/cls-20506995

@gerhardt26, Is this the study that you had in mind?