Arch Diagnostic Imaging is closed, Facility is now operated by Mercy Imaging Center of Alliance. Located inside Carnation Clinic. Computerized Tomography (CT) Open MRI Mercy Imaging Center of Alliance Mercy Medical Center offers radiologic services to the Alliance community with the acquisition of ARCH Diagnostics Imaging. The Alliance facility houses Mercy Medical Center's only open MRI, giving claustrophobic patients an alternative to traditional MRI scans.