CTA Abdomen and Pelvis with Bilateral Lower Extremity Runoff Without and With IV Contrast CTA is commonly used for imaging peripheral vascular disease. Multidetector CT scanners, including helical and multistation axial acquisitions, enable rapid scanning of the entire arterial system [13]. When compared with catheter arteriography, CTA offers volumetric as opposed to planar images. The volumetric acquisition enables extensive image postprocessing, including multiplanar reformatted and maximum-intensity projection images to create an arterial road map [13]. With optimized timing of the acquisition, CT images include collaterals and arteries distal to occlusions that may not appear on catheter angiography images. Like MRA, CTA is a cross-sectional technique, which shows nonvascular findings as well as vascular lesions associated with aneurysms and cystic adventitial disease that are not detected with the projectional technique of catheter arteriography. Unlike imaging of the peripheral arteries, CTA is considered to have replaced catheter angiography as the reference standard for imaging of the aorta [13,14]. CTA can readily detect stenosis caused by plaque or thrombus in the aorta and iliac arteries that may be contributing to symptoms of claudication. CTA alone can be used to plan treatment, including assessment of the length, severity, and number of stenoses [15,16]. Compared with catheter angiography, the sensitivity and specificity of CTA for detection of stenoses >50% diameter are 90% to 100% [10,17-20]. Accuracy in patients with bypass grafts is excellent compared with duplex US [21]. CTA is also more clinically useful than duplex US [21]. However, heavily calcified atheromatous disease can limit the ability to interpret CT images. This drawback is usually more pronounced in tibial arteries.
Lower Extremity Arterial Claudication Imaging Assessment for Revascularization. CTA Abdomen and Pelvis with Bilateral Lower Extremity Runoff Without and With IV Contrast CTA is commonly used for imaging peripheral vascular disease. Multidetector CT scanners, including helical and multistation axial acquisitions, enable rapid scanning of the entire arterial system [13]. When compared with catheter arteriography, CTA offers volumetric as opposed to planar images. The volumetric acquisition enables extensive image postprocessing, including multiplanar reformatted and maximum-intensity projection images to create an arterial road map [13]. With optimized timing of the acquisition, CT images include collaterals and arteries distal to occlusions that may not appear on catheter angiography images. Like MRA, CTA is a cross-sectional technique, which shows nonvascular findings as well as vascular lesions associated with aneurysms and cystic adventitial disease that are not detected with the projectional technique of catheter arteriography. Unlike imaging of the peripheral arteries, CTA is considered to have replaced catheter angiography as the reference standard for imaging of the aorta [13,14]. CTA can readily detect stenosis caused by plaque or thrombus in the aorta and iliac arteries that may be contributing to symptoms of claudication. CTA alone can be used to plan treatment, including assessment of the length, severity, and number of stenoses [15,16]. Compared with catheter angiography, the sensitivity and specificity of CTA for detection of stenoses >50% diameter are 90% to 100% [10,17-20]. Accuracy in patients with bypass grafts is excellent compared with duplex US [21]. CTA is also more clinically useful than duplex US [21]. However, heavily calcified atheromatous disease can limit the ability to interpret CT images. This drawback is usually more pronounced in tibial arteries.