Thoracoabdominal Aortic Aneurysm or Dissection CTA Chest and Abdomen With IV Contrast Compared with CTA of the chest, abdomen, and pelvis, the lack of visualization of the iliofemoral vessels precludes evaluation for suitability for possible endovascular intervention or for aneurysm dilation/dissection of the iliac or femoral arteries if pathology extends to the bifurcation. MRA Chest, Abdomen, and Pelvis Without and With IV Contrast Similar to CTA, MRA of the thoracoabdominal aorta allows for precise and reproducible assessment or aortic sac size in aneurysm or extent of dissection in thoracoabdominal aortic dissection [33,37-39]. In patients with new symptoms, MRI has conventionally been used as a secondary imaging modality because of relatively long imaging times [40]. However, MRI can be used to accurately assess for acute aortic pathology in this clinical setting [40- 42]. Use of a contrast agent in MRA allows for 4-D evaluation of flow dynamics, with acquisition of multiple time- points allowing for detailed evaluation of flow dynamics associated with aortic aneurysm or dissection [43]. This can be used with a variety of unenhanced MRA techniques such as time-of-flight and phase-contrast imaging that can also allow for evaluation of aortic dissection and aneurysm [44,45]. Similar to CTA, ECG gating can be used for a more accurate assessment of the ascending thoracic aorta if concern exists for retrograde extension of pathology [46,47]. MRA can allow for the evaluation of aortic valve dysfunction associated with ascending aortic dilation or dissection, which cannot typically be identified on CTA [33,46,47]. MRI also allows evaluation for extravascular pathology. In a 2014 study, more than 80% of patients had at least one extravascular finding, with 6.4% found to have a major extravascular finding including neoplasm, spine infection, or pericardial effusion [48].
Thoracoabdominal Aneurysm or Dissection Treatment Planning and Follow Up. Thoracoabdominal Aortic Aneurysm or Dissection CTA Chest and Abdomen With IV Contrast Compared with CTA of the chest, abdomen, and pelvis, the lack of visualization of the iliofemoral vessels precludes evaluation for suitability for possible endovascular intervention or for aneurysm dilation/dissection of the iliac or femoral arteries if pathology extends to the bifurcation. MRA Chest, Abdomen, and Pelvis Without and With IV Contrast Similar to CTA, MRA of the thoracoabdominal aorta allows for precise and reproducible assessment or aortic sac size in aneurysm or extent of dissection in thoracoabdominal aortic dissection [33,37-39]. In patients with new symptoms, MRI has conventionally been used as a secondary imaging modality because of relatively long imaging times [40]. However, MRI can be used to accurately assess for acute aortic pathology in this clinical setting [40- 42]. Use of a contrast agent in MRA allows for 4-D evaluation of flow dynamics, with acquisition of multiple time- points allowing for detailed evaluation of flow dynamics associated with aortic aneurysm or dissection [43]. This can be used with a variety of unenhanced MRA techniques such as time-of-flight and phase-contrast imaging that can also allow for evaluation of aortic dissection and aneurysm [44,45]. Similar to CTA, ECG gating can be used for a more accurate assessment of the ascending thoracic aorta if concern exists for retrograde extension of pathology [46,47]. MRA can allow for the evaluation of aortic valve dysfunction associated with ascending aortic dilation or dissection, which cannot typically be identified on CTA [33,46,47]. MRI also allows evaluation for extravascular pathology. In a 2014 study, more than 80% of patients had at least one extravascular finding, with 6.4% found to have a major extravascular finding including neoplasm, spine infection, or pericardial effusion [48].