Peripheral vascular disease continues to be a leading cause of death and disability in the United States and the Western world.1 Advancements in imaging modalities have enhanced our ability to better understand both the anatomy and pathophysiology of vascular diseases. Health care practitioners with a clear understanding of the available imaging modalities and their utilization will be better positioned to optimize outcomes in patients with peripheral vascular diseases.
In this chapter, we present carotid, aortic, and lower extremity atherosclerotic peripheral vascular disease cases with computed tomography angiography (CTA) images that illustrate key points in diagnosis and treatment.
The recent and rapid advancement of computed tomography (CT) scanners from single-row to multidetector-row scanners has greatly enhanced our ability to image the body's vasculature. Wider detector arrays allow for more rapid image acquisition, using less contrast and less radiation dose. Improved spatial resolution of the new generation of scanners also provides more details of the vascular anatomy including plaque morphology characterization. Postprocessing of these rapidly acquired images with three-dimensional (3D) workstations allows viewing of images in multiple planes and with multiple viewing techniques.
CTA imaging has several advantages in peripheral arterial disease: (1) excellent spatial resolution; (2) exceptional sensitivity and specificity; (3) ability to assess postocclusion anatomy; (4) short examination time; (5) ability to accurately assess vasculature that has been revascularized (stented or bypassed); (6) imaging in multiple planes; (7) lack of interference with metal, including cardiac devices; and (8) patient preference and comfort. There is also the added benefit that CTA and magnetic resonance (MR) can potentially allow for the diagnosis of nonvascular abnormalities that may be clinically significant.
The main disadvantages potentially include: (1) nephrotoxic contrast agents; (2) exposure to radiation; and (3) potential "blooming" (partial volume) artifact from excessive calcium in the vascular system.
A 68-year-old man presents to the office of his primary care physician after experiencing several episodes of transient right hand paresthesias that last for less than 1 hour. He has a history of hypertension, dyslipidemia, and known coronary artery disease with three-vessel bypass 5 years prior to presentation. Physical exam is without focal neurologic deficits but does reveal bilateral carotid bruits. Blood pressure is 95/55 mm Hg. A duplex ultrasound (DUS) of the neck is ordered for evaluation.
Carotid DUS shows a "possible complete occlusion" of the left common carotid artery and "mild" disease within the right carotid system. The patient is referred to cardiology, and a CTA of the neck is ordered for further clarification. See Figs. 23–1, 23–2, 23–3.
Left carotid system. Maximum intensity projection view of stenosis (arrow) of the left internal carotid artery with a large plaque burden. The average Hounsfield units of 27 within the plaque indicate low-density lipid-laden plaque.