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Key Clinical Questions
What are the advantages of noncontrast computed tomography (CT) compared with other CT studies?
What are the indications for noncontrast CT with thin-section reconstruction?
When is the use of IV contrast with CT imaging mandatory?
What are the limitations of positron-emission tomography (PET)-CT?
What are the Fleischner Society Guidelines recommendations concerning follow-up of incidental solid and subsolid pulmonary nodules?
What are the main indications for cardiac-CT?
What are the disadvantages of cardiac magnetic resonance with late gadolinium enhancement?
Complementary to two-dimensional echocardiography, transesophageal echocardiography (TEE) is able to provide superior visualization of what cardiac structures?
What calcium score would preclude contrast computed tomography angiography (CTA)?
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The overwhelming majority of advanced chest imaging for hospitalized patients is performed by computed tomography (CT), with ultrasound, magnetic resonance imaging (MRI), and nuclear medicine reserved for specific indications. The evolution of disease processes in the chest is central to the diagnostic process, necessitating integration between modalities in choosing comparison studies over time. An experienced radiologist may provide interpretation of serial bedside chest radiographs with physiologic and pathologic information that may not be available from more advanced imaging that reflects only a single snapshot in time.
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The chief complaint and clinical differential diagnosis should guide decisions about the extent of medical imaging necessary for the proper diagnosis and treatment of the acute illness. The systematic way in which a clinician completes a history and physical examination is similar to the way in which a radiologist systematically analyzes and interprets an image. Both use a checklist that will identify the truly incidental and unrelated findings as well as separate seemingly unrelated findings that complete the picture of acute illness.
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Many patients who require hospitalization for successful care of their acute illness have underlying medical conditions and chronic disease processes. Pre-existing heart disease, lung disease, and systemic disease findings help to develop the personalized differential diagnosis for the reporting of the imaging studies whether obtained as radiographs, CT, MRI or any other modality. Diabetes, collagen vascular diseases, chronic obstructive pulmonary disease, atherosclerosis, and suppression of the immune system may lead the radiologist to different conclusions about the significance of particular findings in an individual patient.
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This chapter will focus on the abnormalities that most frequently require advanced imaging for diagnosis and the common incidental findings that require mandatory follow-up postdischarge.
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NORMAL VERSUS ABNORMAL FUNCTION OF LUNGS
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Blood flow is greater to the lower lobes than the upper lobes, and greatest in the right lower lobe. Hematogenous spread of tumor likely begins in the lung bases due to greater blood flow to this area, particularly the right lower lobe. Pulmonary emboli and septic emboli also occur more often in lower lobes. Oxygenation is greater in the upper lobes. Oxygen-loving mycobacterium organisms prefer the lung apices. Warm cigarette smoke rises most directly to the apical segment of ...