Poster presentation | Open | Published:
Non-contrast fresh-blood MRA for assessment of abdominal endovascular stent grafts
Journal of Cardiovascular Magnetic Resonancevolume 11, Article number: P229 (2009)
Serial imaging of abdominal aortic endovascular stent grafts (AA-ESG) is done in order to determine: 1) stent stability, 2) presence of endograft leak, and 3) residual abdominal aortic aneurysm (AAA) sac size. CT angiography (CTA) has traditionally been used for serial follow-up. Given the high incidence of renal dysfunction in patients with AAA and potential contraindications to both CT and MR contrast agents we development a non-contrast vascular imaging protocol for assessment of patients with AA-ESG.
Consecutive patients who had AAA repair with AA-ESG and had prior CTA for comparison were imaged with a combined black blood (BB) imaging protocol using 2D single-shot FSE for depicting vessel wall dimensions (aneurysm sac size) and a fresh-blood imaging (FBI) technique using 3D single-shot FSE for bright blood imaging of the vessel lumen (stent stability). Comparisons were made in accuracy of endovascular luminal assessment (FBI vs. CTA along 3 points, see Figure 1) and aneurysm wall-to-wall dimensions (BB vs. CTA). The non-contrast technique did not allow direct assessment of endograft leak. CTA was performed on a Toshiba Aquilion 64-slice CT scanner while MRI imaging was performed using a Toshiba Vantage Atlas 1.5 T MRI scanner.
Consecutive patients are reported on (n = 5): 73 ± 4 yo, 45 ± 16 months since AAA repair (mean ± SD). Aneurysm dimension at its greatest size as assessed by CTA (3.9 ± 0.1 cm) was similar to that for BB imaging (3.8 ± 0.1 cm) (p = 0.40). Endograft visualization as assessed by luminal dimensions was similar between FBI and CTA (r2 = 0.96, n = 15) with good visualization of the AA-ESG and surrounding arterial tree.
A combined approach of 2D BB and 3D FBI imaging of AA-ESG can accurately assess aneurysm sac size and endograft angiographic characteristics. Although this non-contrast technique cannot directly assess for endograft leak this approach may still be an acceptable alternative to contrast imaging for serial follow-up of patients with renal dysfunction. Further validation of this novel technique will need to be done in a larger cohort of patients.