Noninvasive Angiography of Peripheral Arteries

Abstract

Technical advances over the past decade have facilitated fast and robust noninvasive imaging of the peripheral vascular tree in routine clinical practice for the entire spectrum of peripheral arterial disease (PAD). Both magnetic resonance angiography (MRA) and computed tomography angiography (CTA) are highly accurate methods that enable highfidelity depiction of arterial anatomy, atherosclerotic plaque, and narrowing of the peripheral vasculature from the aorta down to the feet. In addition, due to their ability to depict extra-arterial anatomy of the entire lower extremity, both methods are well suited for the detection of nonatherosclerotic peripheral arterial disease. Below, we first detail the clinical context and technical background of both MRA and CTA since high-quality peripheral vascular imaging demands careful attention to proper patient positioning and acquisition. We include suggestions for imaging protocols for both modalities. Subsequently, we discuss the most common clinical applications of both MRA and CTA. We conclude with a short discussion of the clinical efficacy of both methods. Key Point • Peripheral arterial disease is highly prevalent in older patients. In patients <45 years old, alternative causes should be considered.

Quantitative hemodynamic assessment of stenotic below‐the‐knee arteries using spatio‐temporal bolus tracking on 4D‐CT angiography

“…[7][8][9] Both run-off CE-MRA and run-off CTA are reliable non-invasive imaging modalities, providing a high accuracy and sensitivity for detecting stenoses in arterial segments from the aorta up to the popliteal artery. 10,11 In run-off CTA, a helical acquisition from the diaphragm to the toes is acquired with intravenous contrast injection. A failure rate of 7.3% in providing an acceptable diagnosis has been reported in the belowthe-knee (BTK) arteries.…”

“…Digital subtraction angiography (DSA) has long been considered the gold standard for evaluating PAD but has been replaced by computed tomography angiography (CTA) and contrast‐enhanced magnetic resonance angiography (CE‐MRA) 7–9 . Both run‐off CE‐MRA and run‐off CTA are reliable non‐invasive imaging modalities, providing a high accuracy and sensitivity for detecting stenoses in arterial segments from the aorta up to the popliteal artery 10,11 …”

Automatic segmentation of peripheral arteries and veins in ferumoxytol‐enhanced MR angiography

“…For the intermediate stages (levels i = 1, 2, 3) of the network, Focal Tversky loss 36 was considered. Equation (7) describes the total loss function used in the network training:…”

“…Contrast‐enhanced magnetic resonance angiography (CE‐MRA) is widely used for the diagnosis of peripheral artery disease 1‐7 . One of the first steps involved in CE‐MRA post‐processing is blood vessel segmentation.…”

“…Contrast-enhanced magnetic resonance angiography (CE-MRA) is widely used for the diagnosis of peripheral artery disease. [1][2][3][4][5][6][7] One of the first steps involved in CE-MRA post-processing is blood vessel segmentation. For more recent steady-state CE-MRA applications using intravascular agents such as ferumoxytol, 8 the post-processing also involves the additional step of separating the arteries from veins, as both arteries and veins are enhanced in these steady-state acquisitions.…”