Endovascular Aortoiliac Aneurysm Repair with Fenestrated Stent Graft and Iliac Side Branch Using Image Fusion without Iodinated Contrast Medium

Benefits and Role of Carbon Dioxide Angiography in Case of Misalignment Between Fenestration and Target Vessel During Fenestrated Endovascular Aneurysm Repair

PURPOSE

To report the benefits and the role of carbon dioxide (CO₂) angiography in case of misalignment between fenestration and target vessel during fenestrated endovascular aneurysm repair (F-EVAR).

TECHNIQUE

During F-EVAR, misalignment between fenestration and target vessel is a potentially catastrophic complication. In 2 patients, we experienced that one of the target vessels were not visible during standard angiography in different projections after positioning a fenestrated graft and even after cannulation of the corresponding fenestration. In both cases, the graft was sealed to the aortic wall but not in the predictable position. Consequently, acute occlusion of the target vessel was hypothesized. However, CO₂ angiography was useful to evaluate patency of the target vessel clarifying the relative position of the fenestration versus the target vessel. Rescue maneuvers were feasible under the guidance of CO₂ angiography in order to obtain the cannulation of both renal arteries. In both cases, the procedure was successfully accomplished.

CONCLUSION

In case of misalignment of a fenestration during F-EVAR and non-visualization of the target vessel with standard angiography, CO₂ angiography could have the unique and complementary role of clarifying the patency and position of the target vessel. In addition, CO₂ could guide the rescue maneuvers.

Performance of a feature-based algorithm for 3D-3D registration of CT angiography to cone-beam CT for endovascular repair of complex abdominal aortic aneurysms

BACKGROUND

A crucial step in image fusion for intraoperative guidance during endovascular procedures is the registration of preoperative computed tomography angiography (CTA) with intraoperative Cone Beam CT (CBCT). Automatic tools for image registration facilitate the 3D image guidance workflow. However their performance is not always satisfactory. The aim of this study is to assess the accuracy of a new fully automatic, feature-based algorithm for 3D3D registration of CTA to CBCT.

METHODS

The feature-based algorithm was tested on clinical image datasets from 14 patients undergoing complex endovascular aortic repair. Deviations in Euclidian distances between vascular as well as bony landmarks were measured and compared to an intensity-based, normalized mutual information algorithm.

RESULTS

The results for the feature-based algorithm showed that the median 3D registration error between the anatomical landmarks of CBCT and CT images was less than 3 mm. The feature-based algorithm showed significantly better accuracy compared to the intensity-based algorithm (p < 0.001).

CONCLUSION

A feature-based algorithm for 3D image registration is presented.

Fluoroscopy with MRA fusion image guidance in endovascular iliac artery interventions: study protocol for a randomized controlled trial (3DMR-Iliac-roadmapping study)

BACKGROUND

Endovascular iliac artery interventions rely on the use of two-dimensional digital subtraction angiographies with an iodinated contrast agent and ionizing radiation. The amount of iodinated contrast agent should be limited because of its potentially nephrotoxic effects. Three-dimensional (3D) image fusion requires registration of a preprocedural magnetic resonance angiogram (MRA) or computed tomography (CT) angiogram to a perprocedurally acquired cone-beam CT or two fluoroscopic orthogonal projections. After registration, the 3D angiography images can be overlaid on the fluoroscopy screen and will follow table and C-arm movements. This study will assess the added value of the 3D image fusion technique in iliac artery interventions regarding the amount of the iodinated contrast agent administered.

METHODS/DESIGN

The study cohort will comprise 106 patients (> 18 years) with symptomatic common and/or external iliac artery stenoses or occlusions and a recent (< 6 months) diagnostic MRA from the pelvis through the lower extremities, for which an endovascular intervention is indicated. Patients will be randomized into the control or study group (i.e. treatment without or with 3D image fusion guidance). The primary endpoint is the amount of administered iodinated contrast agent (mL). Secondary outcomes are technical success of the procedure, defined as < 30% residual stenosis over the treated lesion, fluoroscopy time, and radiation dose as dose area product (mGycm2). Patient participation in the study will be completed after hospital discharge.

DISCUSSION

This study is a randomized controlled multicenter trial to provide evidence on the effect of the 3D image fusion technique on the amount of administered iodinated contrast during endovascular common and/or external iliac artery interventions.

TRIAL REGISTRATION

Nederlands Trial Register, NTR5008 . Registered on 16 December 2014.

Current status of carbon dioxide angiography

OBJECTIVE

Unfamiliarity of endovascular surgeons with carbon dioxide (CO₂) angiography is one of the main reasons for its limited use. This review is intended to familiarize the reader with the principles and applications of that modality.

METHODS

We conducted a comprehensive review of contemporary literature related to CO₂ angiography and its use in the field of vascular and endovascular surgery, including technical details and diagnostic and interventional applications.

RESULTS

Cardinal physicochemical characteristics of CO₂ include buoyancy, ultralow viscosity, and nonmixing with blood. Because of the risk of neurotoxicity, intra-arterial CO₂ angiography should only be performed below the diaphragm. Venous CO₂ angiography can be performed anywhere in the torso and extremities. Ultralow viscosity enables intraprocedural imaging during vascular interventions without the need to exchange for an angiographic catheter. Benefits, advantages, and emerging applications of CO₂ angiography are listed. Potential complications and their avoidance and troubleshooting are discussed.

CONCLUSIONS

CO₂ holds promise as an effective and versatile angiographic contrast agent. It is also a valuable modality for the guidance of endovascular interventions. Current availability of easy to use, safe, and portable CO₂ delivery systems will likely expand the use of that modality even beyond the traditional indications of renal insufficiency and iodinated contrast allergy.