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INTRODUCTION

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.

CHEST RADIOGRAPHY

  • Accessible and should be part of the standard evaluation for pts with cardiopulmonary complaints (FIG. 3-1).

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

  • Often normal in a pt with an acute pulmonary embolus.

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

  • Used in conjunction with the physical examination to support the diagnosis of congestive heart failure. The diagnosis of heart failure is supported by findings of cardiomegaly, cephalization, Kerley B lines, and pleural effusions.

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

  • Features of alveolar or airspace disease 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.

FIGURE 3-1

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.

ABDOMINAL RADIOGRAPHY

  • 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.

  • Used to evaluate the size of bowel:

    1. Normal small bowel is <3 cm in diameter.

    2. Normal caliber of the cecum is up ...

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