Clinicians have a wide array of imaging modalities at their disposal to aid them in noninvasive diagnosis. Despite the introduction of highly specialized imaging modalities, radiologic procedures such as chest radiographs and ultrasound continue to serve a vital role in the diagnostic approach to pt care. Increasingly, ultrasound is used as a point-of-care procedure to assist with intravenous line placement, and to extend the physical examination of the thyroid thorax, heart, and abdomen. At most institutions, CT is available on an emergent basis and is invaluable for initial evaluation of pts with trauma, suspected CNS hemorrhage, or ischemic stroke. MRI and related techniques (MR angiography, functional MRI, MR spectroscopy) provide high resolution of many tissues including the brain, vascular system, joints, and most large organs. Radionuclide scans including positron emission tomography (PET) can provide functional assessment of organs or specific regions within organs. Combination of PET with MRI or CT scanning provides highly informative images of the location and configuration of metabolically active lesions, such as cancers.

This chapter will review the indications and utility of the most commonly utilized radiologic studies used by internists.