Diagnostic x-ray and other imaging tests, when they are not performed as part of a covered surgical admission. These types of tests can be low-tech radiology services, such as ultrasounds or x-rays. Or, they can be high tech radiology services, such as computerized axial tomography (CT scans), magnetic resonance imaging (MRI), positron emission tomography (PET scans), and nuclear cardiac imaging. Imaging tests may pair pictures of the body with functional measurements, such as a barium swallow test.