Following new trends in precision medicine, Juxatarenal Abdominal Aortic Aneurysm (JAAA) treatment has been
enabled by using patient-specific fenestrated endovascular grafts. The X-ray guided procedure requires precise
orientation of multiple modular endografts within the arteries confirmed via radiopaque markers. Patient-specific 3D
printed phantoms could familiarize physicians with complex procedures and new devices in a risk-free simulation
environment to avoid periprocedural complications and improve training. Using the Vascular Modeling Toolkit
(VMTK), 3D Data from a CTA imaging of a patient scheduled for Fenestrated EndoVascular Aortic Repair (FEVAR)
was segmented to isolate the aortic lumen, thrombus, and calcifications. A stereolithographic mesh (STL) was generated
and then modified in Autodesk MeshMixer for fabrication via a Stratasys Eden 260 printer in a flexible photopolymer to
simulate arterial compliance. Fluoroscopic guided simulation of the patient-specific FEVAR procedure was performed
by interventionists using all demonstration endografts and accessory devices. Analysis compared treatment strategy
between the planned procedure, the simulation procedure, and the patient procedure using a derived scoring scheme.
Results: With training on the patient-specific 3D printed AAA phantom, the clinical team optimized their procedural
strategy. Anatomical landmarks and all devices were visible under x-ray during the simulation mimicking the clinical
environment. The actual patient procedure went without complications.
Conclusions: With advances in 3D printing, fabrication of patient specific AAA phantoms is possible. Simulation with
3D printed phantoms shows potential to inform clinical interventional procedures in addition to CTA diagnostic imaging.
3D printing has been used to create complex arterial phantoms to advance device testing and physiological condition
evaluation. Stereolithographic (STL) files of patient-specific cardiovascular anatomy are acquired to build cardiac
vasculature through advanced mesh-manipulation techniques. Management of distal branches in the arterial tree is
important to make such phantoms practicable.
We investigated methods to manage the distal arterial flow resistance and pressure thus creating physiologically and
geometrically accurate phantoms that can be used for simulations of image-guided interventional procedures with
new devices. Patient specific CT data were imported into a Vital Imaging workstation, segmented, and exported as
STL files. Using a mesh-manipulation program (Meshmixer) we created flow models of the coronary tree. Distal
arteries were connected to a compliance chamber. The phantom was then printed using a Stratasys Connex3 multimaterial
printer: the vessel in TangoPlus and the fluid flow simulation chamber in Vero. The model was connected
to a programmable pump and pressure sensors measured flow characteristics through the phantoms. Physiological
flow simulations for patient-specific vasculature were done for six cardiac models (three different vasculatures
comparing two new designs). For the coronary phantom we obtained physiologically relevant waves which
oscillated between 80 and 120 mmHg and a flow rate of ~125 ml/min, within the literature reported values. The
pressure wave was similar with those acquired in human patients. Thus we demonstrated that 3D printed phantoms
can be used not only to reproduce the correct patient anatomy for device testing in image-guided interventions, but
also for physiological simulations. This has great potential to advance treatment assessment and diagnosis.
KEYWORDS: Resistance, Data modeling, Medical research, 3D modeling, Arteries, Computed tomography, Image segmentation, Sensors, 3D image processing, Angiography
Purpose: Accurate patient-specific phantoms for device testing or endovascular treatment planning can be 3D printed. We
expand the applicability of this approach for cardiovascular disease, in particular, for CT-geometry derived benchtop
measurements of Fractional Flow Reserve, the reference standard for determination of significant individual coronary
artery atherosclerotic lesions.
Materials and Methods: Coronary CT Angiography (CTA) images during a single heartbeat were acquired with a
320x0.5mm detector row scanner (Toshiba Aquilion ONE). These coronary CTA images were used to create 4 patientspecific
cardiovascular models with various grades of stenosis: severe, <75% (n=1); moderate, 50-70% (n=1); and mild,
<50% (n=2). DICOM volumetric images were segmented using a 3D workstation (Vitrea, Vital Images); the output was
used to generate STL files (using AutoDesk Meshmixer), and further processed to create 3D printable geometries for flow
experiments. Multi-material printed models (Stratasys Connex3) were connected to a programmable pulsatile pump, and
the pressure was measured proximal and distal to the stenosis using pressure transducers. Compliance chambers were used
before and after the model to modulate the pressure wave. A flow sensor was used to ensure flow rates within physiological
reported values.
Results: 3D model based FFR measurements correlated well with stenosis severity. FFR measurements for each stenosis
grade were: 0.8 severe, 0.7 moderate and 0.88 mild.
Conclusions: 3D printed models of patient-specific coronary arteries allows for accurate benchtop diagnosis of FFR.
This approach can be used as a future diagnostic tool or for testing CT image-based FFR methods.
KEYWORDS: 3D printing, 3D image processing, Image segmentation, 3D modeling, Printing, Image processing, Visualization, Picture Archiving and Communication System, Imaging informatics, Medicine, Cardiology, Heart, Angiography, Fluoroscopy, Imaging systems
3D printing an anatomically accurate, functional flow loop phantom of a patient’s cardiac vasculature was used to assist
in the surgical planning of one of the first native transcatheter mitral valve replacement (TMVR) procedures. CTA scans
were acquired from a patient about to undergo the first minimally-invasive native TMVR procedure at the Gates Vascular
Institute in Buffalo, NY. A python scripting library, the Vascular Modeling Toolkit (VMTK), was used to segment the 3D
geometry of the patient’s cardiac chambers and mitral valve with severe stenosis, calcific in nature. A stereolithographic
(STL) mesh was generated and AutoDesk Meshmixer was used to transform the vascular surface into a functioning closed
flow loop. A Stratasys Objet 500 Connex3 multi-material printer was used to fabricate the phantom with distinguishable
material features of the vasculature and calcified valve. The interventional team performed a mock procedure on the
phantom, embedding valve cages in the model and imaging the phantom with a Toshiba Infinix INFX-8000V 5-axis Carm
bi-Plane angiography system.
Results: After performing the mock-procedure on the cardiac phantom, the cardiologists optimized their transapical
surgical approach. The mitral valve stenosis and calcification were clearly visible. The phantom was used to inform the
sizing of the valve to be implanted.
Conclusion: With advances in image processing and 3D printing technology, it is possible to create realistic patientspecific
phantoms which can act as a guide for the interventional team. Using 3D printed phantoms as a valve sizing
method shows potential as a more informative technique than typical CTA reconstruction alone.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.