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Figure 27-26 A, Anteroposterior (AP) view of a multidetector computed tomography angiogram (CTA) reconstructed with three-dimensional imaging software. This image shows the distal aorta, iliac arteries, common femoral arteries, and proximal superficial femoral arteries. There are minimal plaques in the distal aorta, common iliac arteries, and superficial femoral arteries. B, AP view of a multidetector CTA demonstrating a short total occlusion of the distal left superficial femoral artery (arrowhead). Note surgical clips from prior saphenous vein harvest (thin arrows). Note absence of the left kidney. C, Posterior view of a multidetector CTA demonstrating a long total occlusion of superficial femoral arteries (between arrowheads). These were successfully stented. Again, note vascular clips from prior saphenous vein harvest (thin arrows).

degree of stenosis is usually possible. However, MRA technology requires flow through the vessel to determine where the lumen exists. The pitfall occurs when the vessel runs through the same plane as the frequency of the radio wave. This leads to flow voids, which appear as gaps in the vessel and are frequently overdiagnosed as stenoses. This phenomenon is particularly common at the origin of the renal arteries and throughout the tortuosity of the carotid arteries.

Invasive Imaging

Traditional invasive diagnostic angiography has been the gold standard for diagnosing PVD since the 1950s. This technique involves the percutaneous placement of catheters within the vessel, injecting iodinated contrast through the catheters, and recording fluoroscopic and cineographic images. As with CTA, conventional angiography uses ionizing radiation, and the same relative risks apply. The potential complications include vascular access site injury, pseudoaneurysm or arte-riovenous fistula formation, bleeding, dissection, and ath-eroembolization. For these reasons, and with the advances in noninvasive CTA/MRA imaging, routine diagnostic standalone invasive angiography is not routinely recommended. The only remaining indications for a conventional diagnostic angiogram are an inconclusive or indeterminate CTA/ MRA and at a planned endovascular intervention.

How To Reduce Acne Scarring

How To Reduce Acne Scarring

Acne is a name that is famous in its own right, but for all of the wrong reasons. Most teenagers know, and dread, the very word, as it so prevalently wrecks havoc on their faces throughout their adolescent years.

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