US In cases where thoracic aortic disease does not extend into the abdomen and no cross-sectional imaging of the iliofemoral system is available, US duplex Doppler of the iliofemoral arteries is useful for assessing adequate access. US duplex Doppler allows for assessment of vessel diameter and plaque burden along the anterior aspect of the vessel. In one recent series examining the use of US-guided femoral access in abdominal aortic endovascular aneurysm repair patients, intraoperative US guidance was shown to significantly reduce operative time and access wound complications [68]. Although similar dedicated studies are not available for TEVAR, the underlying principle is directly transferrable. Similarly, IVUS at the time of intervention has been shown to provide reliable information regarding iliofemoral morphology and atherosclerotic disease burden [56]. Radiography Chest radiographs will demonstrate abnormalities in a large percentage of patients with acute thoracic aorta pathology. For example, in patients presenting with acute aortic dissection, >80% demonstrated chest radiograph abnormalities, with mediastinal widening seen in just over 50% of cases [59,69]. However, radiography can only alert to an underlying abnormality and provides no specific information regarding type of pathology or detailed anatomic information necessary for interventional planning. FDG-PET/CT Nuclear medicine studies play a limited role in the workup of acute aortic pathology. In patients presenting with acute type B aortic dissection, greater uptake of fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG) in the aortic wall as seen on positron emission tomography (PET)/CT has been shown to predict rupture and dissection propagation [70]. The optimal CTA protocol for TEVAR follow-up is not well defined. Most commonly a triphasic protocol is performed with acquisition of unenhanced, arterial, and delayed-phase (60-120 seconds after injection) imaging.
Thoracic Aortic Aneurysm or Dissection Treatment Planning and Follow Up. US In cases where thoracic aortic disease does not extend into the abdomen and no cross-sectional imaging of the iliofemoral system is available, US duplex Doppler of the iliofemoral arteries is useful for assessing adequate access. US duplex Doppler allows for assessment of vessel diameter and plaque burden along the anterior aspect of the vessel. In one recent series examining the use of US-guided femoral access in abdominal aortic endovascular aneurysm repair patients, intraoperative US guidance was shown to significantly reduce operative time and access wound complications [68]. Although similar dedicated studies are not available for TEVAR, the underlying principle is directly transferrable. Similarly, IVUS at the time of intervention has been shown to provide reliable information regarding iliofemoral morphology and atherosclerotic disease burden [56]. Radiography Chest radiographs will demonstrate abnormalities in a large percentage of patients with acute thoracic aorta pathology. For example, in patients presenting with acute aortic dissection, >80% demonstrated chest radiograph abnormalities, with mediastinal widening seen in just over 50% of cases [59,69]. However, radiography can only alert to an underlying abnormality and provides no specific information regarding type of pathology or detailed anatomic information necessary for interventional planning. FDG-PET/CT Nuclear medicine studies play a limited role in the workup of acute aortic pathology. In patients presenting with acute type B aortic dissection, greater uptake of fluorine-18-2-fluoro-2-deoxy-D-glucose (FDG) in the aortic wall as seen on positron emission tomography (PET)/CT has been shown to predict rupture and dissection propagation [70]. The optimal CTA protocol for TEVAR follow-up is not well defined. Most commonly a triphasic protocol is performed with acquisition of unenhanced, arterial, and delayed-phase (60-120 seconds after injection) imaging.