These subtraction images have been demonstrated to be nearly equivalent in diagnostic accuracy to those of conventional angiograms, with similar or less radiation using newer protocols [35]. This technique has been improved at some institutions by subtracting the extravascular tissues in multiple segments rather than the entire study at once [36]. Relatively recent advances in CTA technology include the use of dynamic (time-resolved) imaging of the tibial arteries [37], selective ultra- low-dose intra-arterial contrast-enhanced CTA [38], and CO2-enhanced high-pitch CTA [39], all of which show promise in certain circumstances. MRA MRA has been used for many years in patients with PAD for both treatment planning and assessment of procedural success. Continued evolution of this technology and imaging protocols has improved image quality and increased the potential applications. Most MRA protocols provide both source images with excellent soft- tissue differentiation and subtracted images demonstrating the vasculature in 2-D and 3-D representations similar to those provided during conventional angiography. In the current era, the accuracy of CTA and CE-MRA for the detection of hemodynamically significant PAD has become essentially equivalent, with an edge for CTA in the aortoiliac segment and for MRA in the infrageniculate distribution [32]. In diabetics, MRA is considered particularly helpful for runoff evaluation because of its superior ability to detect flow in small, calcified vessels, approaching the sensitivity of digital subtraction angiography (DSA) [40]. Lower Extremity Arterial Revascularization at which each segment is optimally opacified [42]. This technique increases sensitivity, specificity, and accuracy for PAD in all segments of the lower extremity arteries, but most importantly below the knee [43,44]. Time- resolved imaging of the whole limb has also been reported [45].
Lower Extremity Arterial Revascularization Post Therapy Imaging. These subtraction images have been demonstrated to be nearly equivalent in diagnostic accuracy to those of conventional angiograms, with similar or less radiation using newer protocols [35]. This technique has been improved at some institutions by subtracting the extravascular tissues in multiple segments rather than the entire study at once [36]. Relatively recent advances in CTA technology include the use of dynamic (time-resolved) imaging of the tibial arteries [37], selective ultra- low-dose intra-arterial contrast-enhanced CTA [38], and CO2-enhanced high-pitch CTA [39], all of which show promise in certain circumstances. MRA MRA has been used for many years in patients with PAD for both treatment planning and assessment of procedural success. Continued evolution of this technology and imaging protocols has improved image quality and increased the potential applications. Most MRA protocols provide both source images with excellent soft- tissue differentiation and subtracted images demonstrating the vasculature in 2-D and 3-D representations similar to those provided during conventional angiography. In the current era, the accuracy of CTA and CE-MRA for the detection of hemodynamically significant PAD has become essentially equivalent, with an edge for CTA in the aortoiliac segment and for MRA in the infrageniculate distribution [32]. In diabetics, MRA is considered particularly helpful for runoff evaluation because of its superior ability to detect flow in small, calcified vessels, approaching the sensitivity of digital subtraction angiography (DSA) [40]. Lower Extremity Arterial Revascularization at which each segment is optimally opacified [42]. This technique increases sensitivity, specificity, and accuracy for PAD in all segments of the lower extremity arteries, but most importantly below the knee [43,44]. Time- resolved imaging of the whole limb has also been reported [45].