MRA MRA MRI after TEVAR suffers from severe susceptibility to artifacts relating to the stainless steel used in many stent graft types, obscuring surrounding relevant anatomy and limiting evaluation for endoleak [39,84]. One particular Thoracic Aorta Interventional Planning and Follow-Up group in which MRI is a preferred imaging modality is patients in whom nitinol stents are placed. This is because these endografts do not produce susceptibility artifacts, thereby allowing adequate visualization of the underlying vasculature [74]. Various studies have demonstrated comparable to superior sensitivities in detection of endoleak with MRA compared with CTA when such stents are used [87,88]. Additional research has shown that in patients with MR-compatible endografts, unenhanced MRA can reliably assess stent position and geometry, whereas CE- MRA can sufficiently evaluate endograft hemodynamics and aortic diameter [89]. A principal advantage of MRI in the follow-up period is its lack of ionizing radiation. In younger patients in whom cumulative radiation dose from repeat CT examinations is of particular concern, placement of an MR- compatible endograft should strongly be considered so that routine MRI surveillance can be obtained [61]. As noted previously, the use of CE-MRA is limited in cases of severe renal dysfunction and pregnancy. Aortography Given its invasiveness, catheter angiography is not a routine surveillance tool after TEVAR. However, in cases where significant endoleaks are identified on cross-sectional imaging or where the origin of endoleak is unclear, catheter angiography is indispensable for further anatomic characterization as well as definitive treatment [76]. TEE and TTE In cases where the extent of residual aortopathy is confined to the aortic root or proximal aorta dilation, TTE may play an adjunctive surveillance role, reducing the frequency of CT or MR surveillance [61].
Thoracic Aortic Aneurysm or Dissection Treatment Planning and Follow Up. MRA MRA MRI after TEVAR suffers from severe susceptibility to artifacts relating to the stainless steel used in many stent graft types, obscuring surrounding relevant anatomy and limiting evaluation for endoleak [39,84]. One particular Thoracic Aorta Interventional Planning and Follow-Up group in which MRI is a preferred imaging modality is patients in whom nitinol stents are placed. This is because these endografts do not produce susceptibility artifacts, thereby allowing adequate visualization of the underlying vasculature [74]. Various studies have demonstrated comparable to superior sensitivities in detection of endoleak with MRA compared with CTA when such stents are used [87,88]. Additional research has shown that in patients with MR-compatible endografts, unenhanced MRA can reliably assess stent position and geometry, whereas CE- MRA can sufficiently evaluate endograft hemodynamics and aortic diameter [89]. A principal advantage of MRI in the follow-up period is its lack of ionizing radiation. In younger patients in whom cumulative radiation dose from repeat CT examinations is of particular concern, placement of an MR- compatible endograft should strongly be considered so that routine MRI surveillance can be obtained [61]. As noted previously, the use of CE-MRA is limited in cases of severe renal dysfunction and pregnancy. Aortography Given its invasiveness, catheter angiography is not a routine surveillance tool after TEVAR. However, in cases where significant endoleaks are identified on cross-sectional imaging or where the origin of endoleak is unclear, catheter angiography is indispensable for further anatomic characterization as well as definitive treatment [76]. TEE and TTE In cases where the extent of residual aortopathy is confined to the aortic root or proximal aorta dilation, TTE may play an adjunctive surveillance role, reducing the frequency of CT or MR surveillance [61].