Republished: Advanced digital subtraction angiography and MR fusion imaging protocol applied to accurate placement of flow diverter device

Augmented 3D venous navigation for neuroendovascular procedures

Background

Endovascular venous access is increasingly used for the treatment of many cerebrovascular diseases. The quality of venous roadmapping through arterial injection can be problematic because of contrast media dilution, slow flow velocity, and unilateral opacification of the venous system.

Objective

To describe our experience with the VesselNavigator (Philips Healthcare, Best, The Netherlands) in performing live 3D roadmapping for intracranial venous procedures.

Material and methods

Live 3D roadmapping is an image-processing technique that allows dynamic roadmapping of vessels with immediate adaptation to the C-arm movements without the need for contrast injection. For this purpose, 3D MR venography is overlaid on live fluoroscopy images after semiautomatic coregistration. The technique was applied to cases of idiopathic venous stenosis and arteriovenous fistula.

Results

The process of coregistration was performed by the principal operator in <5 min, just before the treatment. The accuracy was controlled peroperatively and was judged satisfactory. Three illustrative cases demonstrate the use of this software for venous navigation and pressure measurement (case 1), venous stenting (case 2), and transvenous embolization of a carotid-cavernous fistula (case 3).

Conclusion

Our preliminary experience suggests that it is a feasible and safe technique for intracranial venous navigation and procedures. The potential lowering of overall radiation dose and contrast media use needs to be verified with further studies.

Treatment of Intra- and Extracranial Aneurysms Using the Flow-Redirection Endoluminal Device: Multicenter Experience and Follow-Up Results

BACKGROUND AND PURPOSE

Flow diversion emerged as a crucial treatment option for intracranial aneurysms. We report a multicenter retrospective analysis of the safety and efficacy in the treatment of intracranial aneurysms with the Flow-Redirection Endoluminal Device (FRED) flow diverter, a dual-layer flow-modulation device.

MATERIALS AND METHODS

All intracranial aneurysms treated with the FRED between March 2013 and February 2016 at 4 neurovascular centers were included. Angiographic and clinical results were retrospectively analyzed, including all follow-up examinations. Aneurysms were unruptured in 44 cases, whereas 8 treatments were due to an acute SAH from the target aneurysm.

RESULTS

Successful implantation of the FRED was possible in 96.2% (50/52) of cases. At 3-month follow-up, complete occlusion was determined in 58.1% (25/43) and near-complete in 25.6% (11/43). At 12-month follow-up, aneurysm occlusion was complete in 75.0% (27/36) and near-complete in 22.2% (8/36). The overall acute and late thromboembolic and hemorrhagic complication rate was 17.3% (9/52), with a permanent treatment-related morbidity and mortality of 4.0% (2/50) and 2.0% (1/50), respectively, to date.

CONCLUSIONS

The FRED device offers an effective tool in the treatment of intracranial aneurysms. The dual-layer design promotes contemporary and stable long-term occlusion rates. Sufficient device expansion should be documented by angiographic CT. Further studies might help to identify a more optimal antiplatelet regimen to avoid thromboembolic complications during the follow-up period.

CBCT-based 3D MRA and angiographic image fusion and MRA image navigation for neuro interventions

Digital subtracted angiography (DSA) remains the gold standard for diagnosis of cerebral vascular diseases and provides intraprocedural guidance. This practice involves extensive usage of x-ray and iodinated contrast medium, which can induce side effects. In this study, we examined the accuracy of 3-dimensional (3D) registration of magnetic resonance angiography (MRA) and DSA imaging for cerebral vessels, and tested the feasibility of using preprocedural MRA for real-time guidance during endovascular procedures.Twenty-three patients with suspected intracranial arterial lesions were enrolled. The contrast medium-enhanced 3D DSA of target vessels were acquired in 19 patients during endovascular procedures, and the images were registered with preprocedural MRA for fusion accuracy evaluation. Low-dose noncontrasted 3D angiography of the skull was performed in the other 4 patients, and registered with the MRA. The MRA was overlaid afterwards with 2D live fluoroscopy to guide endovascular procedures.The 3D registration of the MRA and angiography demonstrated a high accuracy for vessel lesion visualization in all 19 patients examined. Moreover, MRA of the intracranial vessels, registered to the noncontrasted 3D angiography in the 4 patients, provided real-time 3D roadmap to successfully guide the endovascular procedures. Radiation dose to patients and contrast medium usage were shown to be significantly reduced.Three-dimensional MRA and angiography fusion can accurately generate cerebral vasculature images to guide endovascular procedures. The use of the fusion technology could enhance clinical workflow while minimizing contrast medium usage and radiation dose, and hence lowering procedure risks and increasing treatment safety.

Wall Apposition Is a Key Factor for Aneurysm Occlusion after Flow Diversion: A Histologic Evaluation in 41 Rabbits

BACKGROUND AND PURPOSE

Robust wall apposition for flow-diverter stents may be important for endothelialization. Using a large series of experimental aneurysms treated with the Pipeline Embolization Device, the objectives of this study were to 1) assess interobserver agreement for the evaluation of wall apposition on posttreatment DSA and evaluate its association with aneurysm occlusion, and 2) measure the relationship between wall apposition assessed with histology and aneurysm occlusion rate after treatment.

MATERIALS AND METHODS

Saccular aneurysms were created in 41 rabbits and treated with the Pipeline Embolization Device. DSA was performed just after the deployment of the device and at follow-up. Three investigators independently graded wall apposition on posttreatment DSA as good or poor. A histopathologist blinded to the angiographic results graded the wall apposition on histologic samples. We examined the correlation between angiographic occlusion and wall apposition with histology and angiography.

RESULTS

Wall apposition evaluated on histology was strongly associated with saccular aneurysm occlusion. Sensitivity and specificity of wall apposition to predict complete occlusion at follow-up were 76.9% and 84.0%, respectively, with an overall accuracy of 81.6%. In this experimental study, DSA was suboptimal to assess flow-diverter apposition, with moderate interobserver agreement and low accuracy.

CONCLUSIONS

Good wall apposition is strongly associated with complete occlusion after flow-diverter therapy. In this study, DSA was suboptimal for assessing wall apposition of flow-diverter stents. These findings suggest that improved tools for assessing flow diverter-stent wall apposition are highly relevant.

Three-dimensional image fusion of CTA and angiography for real-time guidance during neurointerventional procedures

AIM

To evaluate the accuracy of three-dimensional (3D) images from two modalities-CT angiography (CTA) and digital subtraction angiography (DSA). Additionally, to explore the value of using preprocedural CTA for real-time guidance during neurointerventional procedures.

MATERIALS AND METHODS

25 patients with CTA-confirmed cerebral arterial lesions were enrolled. For 12 of these patients, 3D DSA images of the contrast medium-enhanced target vessel were acquired during the intervention and registered with the preprocedurally acquired CTA images for evaluation of the accuracy of image fusion, focusing on the target vessel and the lesion. For the other 13 patients, a low-dose non-contrast 3D angiographic scan was performed. The preprocedurally acquired CTA image was then registered with the coordinate of angiography and overlaid onto the live fluoroscopic image to provide interventional guidance.

RESULTS

Based on visual inspection by two experienced physicians and quantitative evaluation, excellent accuracy in the 3D registration of the CTA and DSA was achieved for all 12 patients examined. Additionally, CTA could be used successfully to guide the interventional procedures, including both diagnostic DSA and stent treatment. The radiation dose and contrast medium use were compared with those used by conventional interventional procedures and both were found to be significantly reduced.

CONCLUSIONS

3D CTA and angiographic image fusion was approved as highly accurate for neurovasculature. Additionally, using the fusion technique to guide interventional procedures enhanced the workflow, and required much less radiation exposure and contrast medium use, thus helping to reduce potential risks and increase treatment safety.