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Clinicians have a wide array of radiologic modalities at their disposal to aid them in noninvasive diagnosis. Despite the introduction of highly specialized imaging modalities, radiologic tests such as chest radiographs and ultrasound continue to serve a vital role in the diagnostic approach to pt care. 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 remarkable 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. Increasingly, internists are being trained in the use of ultrasound to assist with line placement, thyroid nodules, cardiac sounds, and abdominal abnormalities.

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


  • Can be obtained quickly and should be part of the standard evaluation for pts with cardiopulmonary complaints (Fig. 2-1).

  • Is able to identify life-threatening conditions such as pneumothorax, intraperitoneal air, pulmonary edema, pneumonia, and aortic dissection.

  • Is most often normal in a pt with an acute pulmonary embolus.

  • Should be repeated in 4–6 weeks in a pt with an acute pneumonic process to document resolution of the radiographic infiltrate.

  • Is used in conjunction with the physical examination to support the diagnosis of congestive heart failure. Radiographic findings supporting the diagnosis of heart failure include cardiomegaly, cephalization, Kerley B lines, and pleural effusions.

  • Should be repeated frequently in intubated pts to examine endotracheal tube position and the possibility of barotrauma.

  • Helps to identify alveolar or airspace disease. Radiographic features of such diseases include inhomogeneous, patchy opacities and air-bronchograms.

  • Helps to document the free-flowing nature of pleural effusions. Decubitus views should be obtained to exclude loculated pleural fluid prior to attempts to extract such fluid.


Normal chest radiograph-review of anatomy. 1. Trachea. 2. Carina. 3. Right atrium. 4. Right hemidiaphragm. 5. Aortic knob. 6. Left hilum. 7. Left ventricle. 8. Left hemidiaphragm (with stomach bubble). 9. Retrosternal clear space. 10. Right ventricle. 11. Left hemidiaphragm (with stomach bubble). 12. Left upper lobe bronchus.


  • Should be the initial imaging modality in a pt with suspected bowel obstruction. Signs of small-bowel obstruction on plain radiographs include multiple air-fluid levels, absence of colonic distention, and a “stepladder” appearance of small-bowel loops.

  • Should not be performed with barium enhancement when perforated bowel, portal venous gas, or toxic megacolon is suspected.

  • Is used to evaluate the size of ...

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