Ultrasound imaging during endovascular abdominal aortic aneurysm repair using the Stentor bifurcated endograft

Registration of Real-Time 3-D Ultrasound to Tomographic Images of the Abdominal Aorta

The purpose of this study was to develop an image-based method for registration of real-time 3-D ultrasound to computed tomography (CT) of the abdominal aorta, targeting future use in ultrasound-guided endovascular intervention. We proposed a method in which a surface model of the aortic wall was segmented from CT, and the approximate initial location of this model relative to the ultrasound volume was manually indicated. The model was iteratively transformed to automatically optimize correspondence to the ultrasound data. Feasibility was studied using data from a silicon phantom and in vivo data from a volunteer with previously acquired CT. Through visual evaluation, the ultrasound and CT data were seen to correspond well after registration. Both aortic lumen and branching arteries were well aligned. The processing was done offline, and the registration took approximately 0.2 s per ultrasound volume. The results encourage further patient studies to investigate accuracy, robustness and clinical value of the approach.

Endovascular Treatment of Aortic Disease

A review is given of endovascular treatment for AAA, thoracic aortic aneurysms, dissections as well as complications following previous aortic surgery. In several of these conditions endovascular treatment has advantages like a reduced operative trauma, shorter stay in hospital, and the possibility of treating patients who would have been unfit for open surgery. On the other hand, problems like endoleak, deformation of the endoprosthesis, retrograde filling of the aneurysmal sack, and graft limb occlusion need to be solved before the place of endovascular treatment can be defined. It is possible that the steadily improving quality of the implants as well as the introducer systems will widen the indications for endovascular surgery, but randomised clinical trials are warranted and a longer follow-up period is necessary to draw final conclusions.

Transcatheter, Endovascular Repair of Abdominal Aortic Aneurysm: Feasibility, Noninvasive Diagnosis, Problems, and Follow-Up

Until recently, the repair of an abdominal aortic aneurysm (AAA) required major surgery. Recently, the transcatheter technique has allowed minimally invasive endovascular stenting of infrarenal AAAs. This procedure is less traumatic and is associated with a shorter hospital stay than conservative surgery. With the stent placement, the effective aortic lumen diameter decreases and the aneurysmal space is excluded from the circulation. Ultrasonographic studies have allowed imaging of the abdominal aorta, its main branches, and the endovascular stent. The aortic blood flow after the repair is ideally limited to the stent lumen. Follow-up studies have permitted reevaluation of the aorta and the stent, with special emphasis on the aortic expansion and blood flow within the excluded space. These studies have correlated well with other imaging techniques such as intravascular ultrasound, computed tomography scanning, and aortography.