Use of Synchrotron Radiation to Accurately Assess Cross-Sectional Area Reduction of the Aortic Branch Ostia Caused by Suprarenal Stent Wires
Journal of Endovascular Therapy
Purpose: To compare in vivo the use of synchrotron radiation to computed tomography angiography (CTA) for the measurement of cross-sectional area (CSA) reduction of the aortic branch ostia caused by suprarenal stent-graft wires. Methods: This study was performed with a Zenith stent-graft placed in a phantom of the human aorta to simulate treatment of abdominal aortic aneurysm. Synchrotron radiation scans were performed using beam energies between 40 and 100 keV and spatial resolution of 19.88
... per pixel. CSA reduction of the aortic branch ostia by suprarenal stent wires was calculated based on these exposure factors and compared with measurements from CTA images acquired on a 64-row scanner with slice thicknesses of 1.0, 1.5, and 2.0 mm. Results: Images acquired with synchrotron radiation showed <10% of the CSA occupied by stent wires when a single wire crossed a renal artery ostium and <20% for 2 wires crossing a renovisceral branch ostium. The corresponding areas ranged from 24% to 25% for a single wire and from 40% to 48% for double wires crossing the branch ostia when measured on CT images. The stent wire was accurately assessed on synchrotron radiation with a diameter between 0.38±0.01 mm and 0.53±0.03 mm, which is close to the actual size of 0.47±0.01 mm. The wire diameter measured on CT images was greatly overestimated (1.15±0.01 mm to 1.57±0.02 mm). Conclusion: CTA has inferior spatial resolution that hinders accurate assessment of CSA reduction. This experiment demonstrated the superiority of synchrotron radiation over CTA for more accurate assessment of aortic stent wires and CSA reduction of the aortic branch ostia. Keywords abdominal aortic aneurysm, aorta, branch ostia, cross-sectional area, computed tomography, renal artery, superior mesenteric artery, synchrotron radiation, stent-graft, suprarenal stent wire rate of cardiovascular events in patients with abdominal aortic aneurysm considered unfit for open repair? Results from the randomised EVAR trial 2. Eur J Vasc Endovasc Surg. 2010;39:396-402. 5. Bicknell CD, Cheshire NJ, Riga CV, et al. Treatment of complex aneurysmal disease with fenestrated and branched stent grafts. Eur J Vasc Endovasc Surg. 2009;37:175-181. 6. O'Donnell ME, Sun Z, Winder EJ, et al. Suprarenal fixation of endovascular aortic stent grafts: assessment of medium-term to long-term renal function by analysis of juxtarenal stent morphology. J Vasc Surg. 2007;45:694-700. 7. Greenberg RK, Chuter TA, Lawrence-Brown M, et al. Analysis of renal function after aneurysm repair with a device using suprarenal fixation (Zenith AAA Endovascular Graft) in contrast to open surgical repair. J Vasc Surg. 2004;39:1219-1228. 8. Saratzis AN, Bath MF, Harrison SC, et al. Impact of fenestrated endovascular abdominal aortic aneurysm repair on renal function. J Endovasc Ther. 2015;22:889-896. 17-0124 Sun EDIT Corrected.doc -page 13 9. Sun Z, Mwipatayi BP, Semmens JB, et al. Short to midterm outcomes of fenestrated endovascular grafts in the treatment of abdominal aortic aneurysms: a systematic review. J Endovasc Ther. 2006;13:747-753. 10. Zarkowsky DS, Hicks CW, Bostock IC, et al. Renal dysfunction and the associated decrease in survival after elective endovascular aneurysm repair. J Vasc Surg. 2016;64:1278-1285. 11. Sun Z, O'Donnell M, Winder R, et al. Effect of suprarenal fixation of aortic stent-grafts on renal ostium: Assessment of morphological changes by virtual intravascular endoscopy. J Endovasc Ther. 2007;14:650-660. 12. Sun Z. Helical CT angiography of abdominal aortic aneurysms treated with suprarenal stent-grafting. Cardiovasc Intervent Radiol. 2003;26:290-295. 13. Rydberg J, Kopecky KK, Lalka SG, et al. Stent grafting of abdominal aortic aneurysms: Pre-and postoperative evaluation with multislice helical CT. J Comput Assist Tomogr. 2001;25:580-586. 14. Rozenblit A, Patlas M, Rosenbaum AT, et al. Detection of endoleaks after endovascular repair of abdominal aortic aneurysm repair: value of unenhanced and delayed helical CT acquisitions. Radiology. 2003;227:426-433. 15. Stavropoulos SW, Clark TW, Carpenter JP, et al. Use of CT angiography to classify endoleaks after endovascular repair of abdominal aortic aneurysms. J Vasc Interv Radiol. 2005;16 663-667. 16. Sun Z, Choo GH, Ng KH. Coronary CT angiography: current status and continuing challenges. Br J Radiol. 2012;85:495-510. 17. Sun Z, Almoudi M, Cao Y. CT angiography in the diagnosis of cardiovascular disease: A transformation in cardiovascular CT practice.