Treatment Planning for Image-Guided Neuro-Vascular Interventions Using Patient-Specific 3D Printed Phantoms

Abstract

Minimally invasive endovascular image-guided interventions (EIGIs) are the preferred procedures for treatment of a wide range of vascular disorders. Despite benefits including reduced trauma and recovery time, EIGIs have their own challenges. Remote catheter actuation and challenging anatomical morphology may lead to erroneous endovascular device selections, delays or even complications such as vessel injury. EIGI planning using 3D phantoms would allow interventionists to become familiarized with the patient vessel anatomy by first performing the planned treatment on a phantom under standard operating protocols. In this study the optimal workflow to obtain such phantoms from 3D data for interventionist to practice on prior to an actual procedure was investigated. Patient-specific phantoms and phantoms presenting a wide range of challenging geometries were created. Computed Tomographic Angiography (CTA) data was uploaded into a Vitrea 3D station which allows segmentation and resulting stereo-lithographic files to be exported. The files were uploaded using processing software where preloaded vessel structures were included to create a closed-flow vasculature having structural support. The final file was printed, cleaned, connected to a flow loop and placed in an angiographic room for EIGI practice. Various Circle of Willis and cardiac arterial geometries were used. The phantoms were tested for ischemic stroke treatment, distal catheter navigation, aneurysm stenting and cardiac imaging under angiographic guidance. This method should allow for adjustments to treatment plans to be made before the patient is actually in the procedure room and enabling reduced risk of peri-operative complications or delays.

Keywords: 3D Printing; Additive Manufacturing; DSA; Image Guided Interventions; Neuro-vascular; Patient-Specific Phantoms; Treatment Planning; Vascular Phantoms.

Figure 1

Flow chart of images describing the manufacturing process for a patient specific phantom of a Circle of Willis. The phantom shown is designated as Phantom I for the purpose of this study.

Figure 2

New 3D printed cardiac phantom. Left picture shows a phantom of a nearly completed Circle of Willis. Right picture shows a cardiac phantom. Blue and red arrows indicate the inflow and the outflow, respectively.

Figure 3

(a) A segmented image showing location and configuration of all five aneurysms (b) New aneurysm phantom, phantom II, to be used as a learning tool for physicians and interventionists.

Figure 4

Several printed phantoms put together to better simulate the traversal of the catheter from the entry point in the femoral artery to the treatment site.

Figure 5

Example of a clot retrieving procedure. (a) DSA after clot was placed in the Middle Cerebral arteries, white arrow indicates the location of the clot. (b) Fluoroscopic snapshot of the stent retriever (Solitaire FR) deployment over the clot using a micro-catheter, (black arrow). (c) DSA after clot retrieval showing opened Middle Cerebral Artery. However, fragments of the clot traveled distally (black arrow) occluding smaller vessels.

Figure 6

Pre- and post-treatment fluoroscopic and DSA acquisitions of flow. The black arrow in the DSA images indicates the ACA where flow was reduced post-treatment.

Figure 7

Aneurysm coiling example. (a) Fluoroscopic snapshot of the initial part of the procedure. (b) Detail of the micro-catheter placed in the aneurysm. (c) Final fluoroscopic snapshot of a coil mass placed in the aneurysm dome. (d) DSA showing initial arrival of the bolus contrast.

Figure 8

Aneurysm stent supported coiling example. (a) Fluoroscopic snapshot of the initial part of the procedure with a neurovascular stent deployed across the aneurysm neck (b) Detail of the stent deployed across the aneurysm neck. (c) Final fluoroscopic snapshot of a coil mass placed in the aneurysm dome. (d) DSA showing initial arrival of the bolus contrast. Contrast flow was not significantly reduced, indicating a need for greater occlusion through deployment of additional coils.

Figure 9

Coronary phantom exemplification. (a) Result of an averaged DSA sequence (b) Detail of the coronary arteries, the smallest vessels are around 0.5 mm (c) Final DSA showing initial arrival of the bolus contrast and flow through the coronary arteries