The authors would like to thank the Ulm University Center for Translational Imaging MoMAN for its support.

The study protocol is in compliance with the ethical guidelines of the 1975 Declaration of Helsinki as reflected in a priori approval by the institution&#39;s ethics committee. Written informed consent was obtained from all individual participants included in the study (CSI-Ulm, clinicaltrials.gov NCT02162069).
1. CT Examination
<ol>
	<li>Perform cardiac CT angiography with retrospective ECG-gating using 80 mL of iodinated contrast media injected at a flow rate of 4.0 mL/s followed by a flushing bolus of 70 mL 0.9% saline solution.</li>
	<li>Acquire data cranio-caudally extending from the femoral arteries to the subclavian arteries with the following acquisition parameters: the matrix of 512 &#215; 512 pixels, slice thickness of 1 mm, slice spacing of 0.7 mm.</li>
	<li>Reconstruct images at 30% of the R-R interval using iterative reconstruction algorithm.</li>
</ol>
2. Image Segmentation and Model Generation
<ol>
	<li>Import CT data from an external device or an internal archiving system into image fusion software by drag-and-dropping the dataset or subsets of data for the selected patient into the Patients view within the application.</li>
	<li>Start automatic segmentation of the selected CT volume by double-clicking on the image series. 
	Note: Segmentation of the heart chambers (left and right ventricle, left and right atrium, myocardium) and great vessels (abdominal aorta, vena cava, and coronary sinus) is started automatically and will be displayed in the Segmentation work step.</li>
	<li>Go through the image slices and verify if the edges of the aorta and left ventricle are correctly detected and if necessary edit the automatic segmentation in the Tissue window using the Edit button.</li>
	<li>To perform manual segmentation of additional structures, use the Add button in the Tissue window.</li>
	<li>Use existing editing tools to fill the structure (Inject Dye) and drag the edges of the structure (Drag Edge) in 2D views or remove structure parts with the Free-form Cut in the 3D view.</li>
	<li>Perform manual segmentation of the main trunks of the left and right coronary arteries, main artery branches (brachiocephalic artery with right carotid and right subclavian arteries, left common carotid artery and left subclavian artery), left and right iliofemoral arteries, hip bones, and hip joints as described in steps 2.4-2.5 (Figure 1). 
	Note: Depending on the quality of the CT volume this may take 20 to 30 min.</li>
</ol>
3. Image Co-registration and Fusion
<ol>
	<li>In the Patients view merge the selected patient with the current patient in the XR system by choosing the respective action in the right-click-context-menu. 
	Note: Now the Registration and Live work steps are active and can be used.</li>
	<li>In the Live work step, click Add new tag point in the Tag points window to place three reference markers at aortic valve cusps for facilitating the choice of the optimal projection of the annular plane during the intervention (Figure 2).</li>
	<li>Go to the Registration work step to acquire the XR runs and to perform the co-registration of the segmented models with XR. 
	Note: XR runs acquired with at least 30&#176; angular distance are required for reliable registration.</li>
	<li>Copy the angiographic projection of the appropriate puncture in ~LAO 20 - 30&#176; orientation (or ~RAO 20 - 30&#176; depending on the initial puncture side) into the Reference view 1 by clicking the button Copy to Reference View 1.</li>
	<li>Copy following x-ray projections acquired in ~AP orientation during visualization of the transition from the contralateral A. iliaca communis to the A. femoralis communis into the Reference view 2 by clicking the button Copy to Reference View 2.</li>
	<li>Use the interaction tools Registration Pan, Registration Rotate (for in-plane rotation), Registration Roll (for 3D rotation) to manually align the model of the iliofemoral arteries with the acquired XR projections (Figure 3A-B).</li>
	<li>Use hip bones and hip joints visible in the XR images as additional landmarks during alignment of the overlay in the iliofemoral region. 
	Note: Now the model is linked to the XR system geometry, and the overlay is automatically being adapted to the current XR projection orientation, magnification, and patient table position.</li>
	<li>Guide the puncture of the common femoral artery on the sheath side (Figure 3C) by using the coarse initial co-registration performed in step 3.6.</li>
	<li>Record an angiographic projection of the device sheath femoral artery in ~RAO 20 - 30&#176; (or respectively ~LAO 20 - 30&#176;) by clicking the button Copy to Reference View and finalize the image co-registration in the iliofemoral region (Figure 3D). 
	Note: Since the patient is positioned differently during CT scan and the intervention, registration based on the iliofemoral structures provides only limited accuracy in other regions. Thus, manual refinement of the co-registration in the thoracic region is required.</li>
	<li>To use these data for further overlay re-alignment, copy any additional acquired projections to the &#8220;Reference View&#8221; during the transition from the iliofemoral to the thoracic region as well as any catheterization of the brachiocephalic trunk via the right radial artery.</li>
	<li>After placing the pigtail catheter in the aortic arch, acquire two fluoroscopic projections without CA in LAO 30 - 40&#176; and RAO 20 - 30&#176; orientation and copy them in the Reference view 1 and Reference view 2.</li>
	<li>Use the interaction tools Registration Pan, Registration Rotate (for in-plane rotation), Registration Roll (for 3D rotation) to manually adjust the registration in the thoracic region (Figure 4A-B).</li>
	<li>Guide the placement of the protection device without administration of additional CA purely based on the anatomic overlay (Figure 4C).</li>
	<li>For further refinement, manually correct the overlay position as described in step 3.12&#160;on each acquired XR projection during the entire course of the intervention, ensuring accurate overlay at any time point. 
	Note: Use aortograms acquired according to the routine procedure for verifying the correct position of the delivery system as landmarks for the overlay adjustment (Figure 4D).</li>
</ol>

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M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fusion+of+CT+Angiography+or+MR+Angiography+with+Unenhanced+CBCT+and+Fluoroscopy+Guidance+in+Endovascular+Treatments+of+Aorto-Iliac+Steno-Occlusion:+Technical+Note+on+a+Preliminary+Experience.">Fusion of CT Angiography or MR Angiography with Unenhanced CBCT and Fluoroscopy Guidance in Endovascular Treatments of Aorto-Iliac Steno-Occlusion: Technical Note on a Preliminary Experience.</a> CardioVascular and Interventional Radiology. 39 (1), 111-116 (2015).</li><li>Sailer, A. 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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcatheter+Aortic+Valve+Replacement+(TAVR):+Access+Planning+and+Strategies.">Transcatheter Aortic Valve Replacement (TAVR): Access Planning and Strategies.</a> Methodist DeBakey Cardiovascular Journal. 8 (2), 22-25 (2012).</li><li>W&#246;hrle, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfemoral+Aortic+Valve+Implantation+with+the+New+Edwards+Sapien+3+Valve+for+Treatment+of+Severe+Aortic+Stenosis-Impact+of+Valve+Size+in+a+Single+Center+Experience.">Transfemoral Aortic Valve Implantation with the New Edwards Sapien 3 Valve for Treatment of Severe Aortic Stenosis-Impact of Valve Size in a Single Center Experience.</a> PLOS ONE. 11 (3), e0151247 (2016).</li><li>Seeger, J., Gonska, B., Otto, M., Rottbauer, W., W&#246;hrle, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cerebral+Embolic+Protection+During+Transcatheter+Aortic+Valve+Replacement+Significantly+Reduces+Death+and+Stroke+Compared+With+Unprotected+Procedures.">Cerebral Embolic Protection During Transcatheter Aortic Valve Replacement Significantly Reduces Death and Stroke Compared With Unprotected Procedures.</a> JACC: Cardiovascular Interventions. 10 (22), 2297-2303 (2017).</li><li>Seeger, J., Gonska, B., Rodewald, C., Rottbauer, W., W&#246;hrle, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+suture+mediated+femoral+access+site+closure+with+the+Prostar+XL+compared+to+the+ProGlide+system+on+outcome+in+transfemoral+aortic+valve+implantation.">Impact of suture mediated femoral access site closure with the Prostar XL compared to the ProGlide system on outcome in transfemoral aortic valve implantation.</a> International Journal of Cardiology. 223, 564-567 (2016).</li><li>Vernikouskaya, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patient-specific+registration+of+3D+CT+angiography+(CTA)+with+X-ray+fluoroscopy+for+image+fusion+during+transcatheter+aortic+valve+implantation+(TAVI)+increases+performance+of+the+procedure.">Patient-specific registration of 3D CT angiography (CTA) with X-ray fluoroscopy for image fusion during transcatheter aortic valve implantation (TAVI) increases performance of the procedure.</a> Clinical Research in Cardiology. , (2018).</li><li>Eng, M. H., Kim, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluoroscopy+and+CT+fusion+overlay-greater+than+the+sum+of+their+parts.">Fluoroscopy and CT fusion overlay-greater than the sum of their parts.</a> Catheterization and Cardiovascular Interventions. 85 (1), 148-149 (2015).</li><li>John, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=System+to+guide+transcatheter+aortic+valve+implantations+based+on+interventional+C-arm+CT+imaging.">System to guide transcatheter aortic valve implantations based on interventional C-arm CT imaging.</a> Medical Image Computing and Computer-Assisted Intervention. 13 (Pt 1), 375-382 (2010).</li><li>Lu, Y., Sun, Y., Liao, R., Ong, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+pre-operative+CT+and+non-contrast-enhanced+C-arm+CT+registration+framework+for+trans-catheter+aortic+valve+implantation.">A pre-operative CT and non-contrast-enhanced C-arm CT registration framework for trans-catheter aortic valve implantation.</a> Computerized Medical Imaging and Graphics. 38 (8), 683-695 (2014).</li></ol>

On behalf of all authors, the corresponding authors state that there are no relationships that could be construed as a conflict of interest.

The main focus of this study was to investigate the feasibility of IF without modifying the clinically established TAVI workflow. Whereas the gold standard for the co-registration of the pre-interventional CTA data and XR fluoroscopy uses dedicated aortograms8, we propose using multiple approximate registrations with on-the-fly refinements to provide accurate 3D model overlay during the entire course of the intervention.
The continuous manual registration refinement req...

Image fusion (IF) is the process of superimposing datasets acquired at the different time- and viewpoints on different modalities into a single-frame of reference1. XR is the most frequently used imaging modality for intervention guidance. Even though, providing high temporal and spatial resolution, XR has low dimensionality (2D projections) and lacks anatomical details. 3D organ shape models derived from e.g. high-quality pre-interventional CTA data superimposed onto the live fluoroscopy image can augment XR by relevant anatomic soft-tissue structures. Prerequisite step for IF is the co-registration of the different imaging modalities.
Typically, co-registration of preoperative 3D image datasets with XR fluoroscopy involves one of the following techniques2: a) image-based 3D-3D registration of the preoperative 3D dataset with an intraoperative non-/contrast-enhanced CBCT dataset3,4,5,6, or b) direct image-based 2D-3D registration, where two angiographic images with a minimum of 30&#176; angular spacing7,8 are used for co-registration.
With the recent introduction of fusion packages on commercial XR systems, IF can be made more readily available for a wide range of applications. Using those systems, we have previously shown that it is technically feasible and safe to overlay an aortic root model by means of direct image-based 2D-3D registration for supporting transfemoral transcatheter aortic valve implantation (TAVI)8. Without compromising the overall CA or XR dose, IF proved itself highly valuable during TAVI procedure by adding 3D anatomical details to the conventional XR fluoroscopy image, especially during deployment of the cerebral protection device. However, the additional acquisition of the aortograms used for the co-registration required additional CA and XR dose. Therefore, an optimized workflow providing accurate IF without the need of any additional aortograms was highly desirable.
Here, we present an approach to improved co-registration of pre-interventional CTA with real-time XR without requiring any additional CA or C-arm CT scans for IF. The femoral access TAVI is performed as described elsewhere9,10,11. Briefly, both femoral arteries are accessed: one for the guidance of the contralateral puncture, followed by placement of a pigtail catheter through a 6F sheath to allow arteriography during placement of the valve prosthesis; the second for placement of the valve delivery system and subsequent balloon valvuloplasty and device placement. Angiographic confirmation of appropriate puncture is performed in our institution as a standard of care for localization of the puncture height (above the femoral bifurcation) and estimation of the position of the covered stent in case of access-related complications12. For capturing embolic debris, a double-filter cerebral protection system is introduced after insertion of the TAVI delivery sheath prior to the passage of the aortic arch with any further device.
We use arteriograms performed routinely during the puncture of the femoral arteries to establish the initial co-registration. On-the-fly refinement of the co-registration is subsequently performed during the on-going procedure using the position of the pigtail catheter within the aortic root, the double-filter cerebral embolic protection system in the supraaortal vessels and the aortograms performed before the implantation of the valve prosthesis, thus ensuring accurate model overlay at any time point during the intervention.

<table><tbody><tr><td>Philips Allura FD10&amp;nbsp;&amp;nbsp;</td><td>Philips Healthcare</td><td></td><td>x-ray system</td></tr><tr><td>EP Navigator Release 5.2.10</td><td>Philips Healthcare</td><td></td><td>image segmentation and fusion SW</td></tr><tr><td>Iomeron 350</td><td>Bracco Imaging Deutschland GmbH</td><td></td><td>x-ray contrast agent</td></tr><tr><td>Sentinel&amp;nbsp; double-filter cerebral protection system</td><td>Claret Medical, Inc.</td><td></td><td>double-filter cerebral protection system&amp;nbsp;</td></tr><tr><td>Matlab R2013</td><td>MathWorks</td><td></td><td>statistical analysis</td></tr></tbody></table>

improved registration of 3d ct angiography with x-ray fluoroscopy for image fusion during transcatheter aortic valve implantation

The fusion of 3D anatomical models derived from high-fidelity pre-interventional computed tomography angiography (CTA), and x-ray (XR) fluoroscopy to facilitate anatomical guidance is of huge interest for complex cardiac interventions like TAVI procedures with cerebral protection. Co-registration of CTA and XR has been introduced either based on additional intraoperative non-/contrast-enhanced cone-beam computed tomography (CBCT) or two separate aortograms. With the related increase of radiation exposure and/or contrast agent (CA) dose, a potential additional risk for the patient is introduced. Here, we propose a modified co-registration approach making use of arteriograms of the iliofemoral arteries, routinely performed during the femoral puncture and sheath introduction. On-the-fly refinement of the co-registration during the on-going procedure enables accurate co-registration without any additional angiograms, thus reducing CA, XR dose and procedure time, while simultaneously improving operator confidence and procedure safety.

We introduced a novel co-registration approach for image fusion during TAVI, which allows overlaying the patient-specific anatomic model onto the live XR images during the entire TAVI procedure without the need for any additional aortograms.
Several interventional steps will benefit from the IF: (1) guidance of the puncture of the common femoral artery above the femoral bifurcation on the sheath side (Figure...

Watch this Scientific Journal Video about Improved Registration of 3D CT Angiography with X-ray Fluoroscopy for Image Fusion During Transcatheter Aortic Valve Implantation at JoVE.com

Improved Registration of 3D CT Angiography with X-ray Fluoroscopy for Image Fusion During Transcatheter Aortic Valve Implantation

The aim of this study was to improve the co-registration for image fusion (IF) of pre-interventional CT data with real-time x-ray (XR) fluoroscopy during transfemoral transcatheter aortic valve implantation (TAVI).

The fusion of 3D anatomical models derived from high-fidelity pre-interventional computed tomography angiography (CTA), and x-ray (XR) fluoroscopy to ...

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10.5K Views.  Ulm University Medical Center. Het doel van deze studie was om de co registratie voor afbeelding fusion (IF) voor vooraf Interventionele CT data met real-time x-ray (XR) fluoroscopie tijdens transfemoral transcatheter aortaklep implantatie (TAVI).

Video: Improved Registration of 3D CT Angiography with X-ray Fluoroscopy for Image Fusion During Transcatheter Aortic Valve Implantation

Intracranial Implantation with Subsequent 3D In Vivo Bioluminescent Imaging of Murine Gliomas

The mouse glioma 261 (GL261) is recognized as an in vivo model system that recapitulates many of the features of human glioblastoma multiforme (GBM). The cell line was originally induced by intracranial injection of 3-methyl-cholantrene into a C57BL/6 syngeneic mouse strain 1; therefore, immunologically competent C57BL/6 mice can be used. While we use GL261, the following protocol can be used for the implantation and monitoring of any intracranial mouse tumor model. GL261 cells were engineered to stably express firefly luciferase (GL261-luc). We also created the brighter GL261-luc2 cell line by stable transfection of the luc2 gene expressed from the CMV promoter. C57BL/6-cBrd/cBrd/Cr mice (albino variant of C57BL/6) from the National Cancer Institute, Frederick, MD were used to eliminate the light attenuation caused by black skin and fur. With the use of albino C57BL/6 mice; in vivo imaging using the IVIS Spectrum in vivo imaging system is possible from the day of implantation (Caliper Life Sciences, Hopkinton, MA). The GL261-luc and GL261-luc2 cell lines showed the same in vivo behavior as the parental GL261 cells. Some of the shared histological features present in human GBMs and this mouse model include: tumor necrosis, pseudopalisades, neovascularization, invasion, hypercellularity, and inflammation 1.
Prior to implantation animals were anesthetized by an intraperitoneal injection of ketamine (50 mg/kg), xylazine (5 mg/kg) and buprenorphine (0.05 mg/kg), placed in a stereotactic apparatus and an incision was made with a scalpel over the cranial midline. A burrhole was made 0.1mm posterior to the bregma and 2.3mm to the right of the midline. A needle was inserted to a depth of 3mm and withdrawn 0.4mm to a depth of 2.6mm. Two &mu;l of GL261-luc or GL261-luc2 cells (107 cells/ml) were infused over the course of 3 minutes. The burrhole was closed with bonewax and the incision was sutured.
Following stereotactic implantation the bioluminescent cells are detectable from the day of implantation and the tumor can be analyzed using the 3D image reconstruction feature of the IVIS Spectrum instrument. Animals receive a subcutaneous injection of 150&mu;g luciferin /kg body weight 20 min prior to imaging. Tumor burden is quantified using mean tumor bioluminescence over time. Tumor-bearing mice were observed daily to assess morbidity and were euthanized when one or more of the following symptoms are present: lethargy, failure to ambulate, hunched posture, failure to groom, anorexia resulting in &gt;10% loss of weight. Tumors were evident in all of the animals on necropsy.

Intracranial Implantation with Subsequent 3D In Vivo Bioluminescent Imaging of Murine Gliomas

Intracranial implantation of GL261 cells into C57BL/6 mice produces malignant gliomas that recapitulate many of the hallmarks of human glioblastoma multiforme. We used GL261 cells stably expressing luciferase to allow us to use in vivo imaging to follow tumor progression. The surgery and 3D in vivo imaging are demonstrated.

The mouse glioma 261 (GL261) is recognized as an in vivo model system that recapitulates many of the features of human glioblastoma multiforme (GBM). The ...

Dual-phase Cone-beam Computed Tomography to See, Reach, and Treat Hepatocellular Carcinoma during Drug-eluting Beads Transarterial Chemo-embolization

The advent of cone-beam computed tomography (CBCT) in the angiography suite has been revolutionary in interventional radiology. CBCT offers 3 dimensional&#160;(3D) diagnostic imaging in the interventional suite and can enhance minimally-invasive therapy beyond the limitations of 2D angiography alone. The role of CBCT has been recognized in transarterial chemo-embolization (TACE) treatment of hepatocellular carcinoma (HCC). The recent introduction of a CBCT technique: dual-phase CBCT (DP-CBCT) improves intra-arterial HCC treatment with drug-eluting beads (DEB-TACE). DP-CBCT can be used to localize liver tumors with the diagnostic accuracy of multi-phasic multidetector computed tomography (M-MDCT) and contrast enhanced magnetic resonance imaging (CE-MRI) (See the tumor), to guide intra-arterially guidewire and microcatheter to the desired location for selective therapy (Reach the tumor), and to evaluate treatment success during the procedure (Treat the tumor). The purpose of this manuscript is to illustrate how DP-CBCT is used in DEB-TACE to see, reach, and treat HCC.

Dual-phase cone-beam computed tomography (DP-CBCT) is a useful intraprocedural imaging technique for transarterial chemo-embolization treatment with drug-eluting beads of hepatocellular carcinoma. DP-CBCT has been used to perform three major steps in oncologic interventional radiology: tumor localization (see), navigation and intraprocedural catheter guidance (reach), and intraprocedural evaluation of treatment success (treat).

The advent of cone-beam computed tomography (CBCT) in the angiography suite has been revolutionary in interventional radiology. CBCT offers 3 ...

Two-Dimensional X-Ray Angiography to Examine Fine Vascular Structure Using a Silicone Rubber Injection Compound

Angiography is an essential tool for the study of vascular structures in various research fields. The aim of this study is to introduce a simple angiographic method for examining the fine vascular structure of unfixed, fresh tissue using a silicone rubber injection compound and soft tissue X-ray system. This study is especially focused on flap territories used in reconstructive surgery. This study employs angiography with a silicone rubber injection compound in various experimental conditions using Sprague-Dawley rats. First, 15 mL of MV compound and 15 mL of diluent is mixed. Then, 1.5 mL of the curing agent is prepared, and a 24G catheter is cannulated in the common carotid artery of the rat. A three-way stopcock is then connected to a catheter, and the radiopaque agent, after being mixed with the prepared curing agent, is injected immediately without spillage. Finally, as the agent solidifies, the specimen is harvested, and an angiographic image is obtained using a soft tissue X-ray system. This method indicates that high-quality angiography showing fine vascular structures can be easily and simply obtained within in a short period of time.

This study presents a simple two-dimensional angiographic method to examine fine vascular structures using a silicone rubber injection compound and soft tissue X-ray system.

Angiography is an essential tool for the study of vascular structures in various research fields. The aim of this study is to introduce a simple ...

Three-Dimensional Printing of a Complex Aortic Anomaly

Complex congenital aortic anomalies include diverse types of malformations that may be clinically asymptomatic or present with respiratory or esophageal symptoms. These anomalies may be associated with other congenital heart diseases. It is hard to identify the accurate anatomic vessel location from two-dimensional imaging data, such as computed tomography. As an additive manufacturing method, three-dimensional (3-D) printing can covert the acquired imaging data into 3-D physical models. This protocol describes the procedure for modeling the volumetric DICOM imaging into 3-D data and printing it as an anatomically realistic 3-D model. Using this model, surgeons can identify the vessel location of complex aortic anomalies, which is helpful for pre-operative planning and intra-operative guidance.

Here, we present a protocol to use three dimensional printed models for pre-operative planning and intra-operative reorganization of complicated vascular locations when handling a congenital aortic anomaly.

Complex congenital aortic anomalies include diverse types of malformations that may be clinically asymptomatic or present with respiratory or esophageal ...

Development and Evaluation of 3D-Printed Cardiovascular Phantoms for Interventional Planning and Training

Catheter-based interventions are standard treatment options for cardiovascular pathologies. Therefore, patient-specific models could help training physicians&#39; wire-skills as well as improving planning of interventional procedures. The aim of this study was to develop a manufacturing process of patient-specific 3D-printed models for cardiovascular interventions.
To create a 3D-printed elastic phantom, different 3D-printing materials were compared to porcine biological tissues (i.e., aortic tissue) in terms of mechanical characteristics. A fitting material was selected based on comparative tensile tests and specific material thicknesses were defined. Anonymized contrast-enhanced CT-datasets were collected retrospectively. Patient-specific volumetric models were extracted from these datasets and subsequently 3D-printed. A pulsatile flow loop was constructed to simulate the intraluminal blood flow during interventions. Models&#39; suitability for clinical imaging was assessed by x-ray imaging, CT, 4D-MRI and (Doppler) ultrasonography. Contrast medium was used to enhance visibility in x-ray-based imaging. Different catheterization techniques were applied to evaluate the 3D-printed phantoms in physicians&#39; training as well as for pre-interventional therapy planning.
Printed models showed a high printing resolution (~30 &#181;m) and mechanical properties of the chosen material were comparable to physiological biomechanics. Physical and digital models showed high anatomical accuracy when compared to the underlying radiological dataset. Printed models were suitable for ultrasonic imaging as well as standard x-rays. Doppler ultrasonography and 4D-MRI displayed flow patterns and landmark characteristics (i.e., turbulence, wall shear stress) matching native data. In a catheter-based laboratory setting, patient-specific phantoms were easy to catheterize. Therapy planning and training of interventional procedures on challenging anatomies (e.g., congenital heart disease (CHD)) was possible.
Flexible patient-specific cardiovascular phantoms were 3D-printed, and the application of common clinical imaging techniques was possible. This new process is ideal as a training tool for catheter-based (electrophysiological) interventions and can be used in patient-specific therapy planning.

Here we present development of a mock circulation setup for multimodal therapy evaluation, pre-interventional planning, and physician-training on cardiovascular anatomies. With the application of patient-specific tomographic scans, this setup is ideal for therapeutic approaches, training, and education in individualized medicine.

Catheter-based interventions are standard treatment options for cardiovascular pathologies. Therefore, patient-specific models could help training ...

Time-Resolved, Dynamic Computed Tomography Angiography for Characterization of Aortic Endoleaks and Treatment Guidance via 2D-3D Fusion-Imaging

In the United States, more than 80% of all abdominal aortic aneurysms are treated by endovascular aortic aneurysm repair (EVAR). The endovascular approach warrants good early results, but adequate follow-up imaging after EVAR is imperative to maintain long-term positive outcomes. Potential graft-related complications are graft migration, infection, fraction, and endoleaks, with the last one being the most common. The most frequently used imaging after EVAR is computed tomography angiography (CTA) and duplex ultrasound. Dynamic, time-resolved computed tomography angiography (d-CTA) is a reasonably new technique to characterize the endoleaks. Multiple scans are done sequentially around the endograft during acquisition that grants good visualization of the contrast passage and graft-related complications. This high diagnostic accuracy of d-CTA can be implemented into therapy via image fusion and reduce additional radiation and contrast material exposure.
This protocol describes the technical aspects of this modality: patient selection, preliminary image review, d-CTA scan acquisition, image processing, qualitative and quantitative endoleak characterization. The steps of integrating dynamic CTA into intra-operative fluoroscopy using 2D-3D fusion-imaging to facilitate targeted embolization are also demonstrated. In conclusion, time-resolved, dynamic CTA is an ideal modality for endoleak characterization with additional quantitative analysis. It can reduce radiation and iodinated contrast material exposure during endoleak treatment by guiding interventions.

Time-Resolved, Dynamic Computed Tomography Angiography for Characterization of Aortic Endoleaks and Treatment Guidance via 2D-3D Fusion-Imaging

Dynamic computed tomography angiography (CTA) imaging provides additional diagnostic value in characterizing aortic endoleaks. This protocol describes a qualitative and quantitative approach using time-attenuation curve analysis to characterize endoleaks. The technique of integrating dynamic CTA imaging with fluoroscopy using 2D-3D image fusion is illustrated for better image guidance during treatment.

In the United States, more than 80% of all abdominal aortic aneurysms are treated by endovascular aortic aneurysm repair (EVAR). The endovascular approach ...

Four-Dimensional Computed Tomography-Guided Valve Sizing for Transcatheter Pulmonary Valve Replacement

The measurements of the right ventricle (RV) and pulmonary artery (PA), for selecting the optimal prosthesis size for transcatheter pulmonary valve replacement (TPVR), vary considerably. Three-dimensional (3D) computed tomography (CT) imaging for device size prediction is insufficient to assess the displacement of the right ventricular outflow tract (RVOT) and PA, which could increase the risk of stent misplacement and paravalvular leak. The aim of this study is to provide a dynamic model to visualize and quantify the anatomy of the RVOT to PA over the entire cardiac cycle by four-dimensional (4D) cardiac CT reconstruction to obtain an accurate quantitative evaluation of the required valve size. In this pilot study, cardiac CT from sheep J was chosen to illustrate the procedures. 3D cardiac CT was imported into 3D reconstruction software to build a 4D sequence which was divided into eleven frames over the cardiac cycle to visualize the deformation of the heart. Diameter, cross-sectional area, and circumference of five imaging planes at the main PA, sinotubular junction, sinus, basal plane of the pulmonary valve (BPV), and RVOT were measured at each frame in 4D straightened models prior to valve implantation to predict the valve size. Meanwhile, dynamic changes in the RV volume were also measured to evaluate right ventricular ejection fraction (RVEF). 3D measurements at the end of the diastole were obtained for comparison with the 4D measurements. In sheep J, 4D CT measurements from the straightened model resulted in the same choice of valve size for TPVR (30 mm) as 3D measurements. The RVEF of sheep J from pre-CT was 62.1 %. In contrast with 3D CT, the straightened 4D reconstruction model not only enabled accurate prediction for valve size selection for TPVR but also provided an ideal virtual reality, thus presenting a promising method for TPVR and the innovation of TPVR devices.

This study assessed a new methodology with a straightened model generated from the four-dimensional cardiac computed tomography sequence to obtain the desired measurements for valve sizing in the application of transcatheter pulmonary valve replacement.

The measurements of the right ventricle (RV) and pulmonary artery (PA), for selecting the optimal prosthesis size for transcatheter pulmonary valve ...

Intravascular Lithotripsy-Assisted Transfemoral Transcatheter Aortic Valve Implantation

During the last decade, transcatheter aortic valve implantation (TAVI) has evolved as a well-established therapy for aging patients suffering from symptomatic severe aortic valve stenosis. This is also reflected in the recently updated international guidelines on managing patients with valvular heart disease. A transfemoral&#160;(TF) TAVI&#160;approach has proven superior to alternative access strategies. With the introduction of intravascular lithotripsy (IVL), patients with calcified iliofemoral vascular disease and borderline intraluminal diameters have also become candidates for percutaneous TF-TAVI. Moreover, IVL reduces the risk of major vascular complications by modifying the superficial and deep vascular calcium, thereby changing the vessel compliance and controlling luminal expansion. In this way, IVL has shown to safely facilitate TF delivery of TAVI devices in patients with calcified peripheral artery disease. The present article aims to provide a detailed step-by-step description on how to perform IVL-assisted TF-TAVI safely and efficiently. Furthermore, a literature review on the outcomes obtained with this technology is included, along with a concise discussion on this unique TAVI approach.

Transcatheter aortic valve implantation (TAVI) has been shown to generate the best clinical outcomes when performed by the percutaneous transfemoral approach. Intravascular lithotripsy (IVL) can facilitate a transfemoral process in patients with calcified iliofemoral vascular disease and borderline intraluminal diameters. The present protocol describes IVL-assisted transfemoral TAVI.

During the last decade, transcatheter aortic valve implantation (TAVI) has evolved as a well-established therapy for aging patients suffering from ...

Reduction of Radiation Exposure during Endovascular Treatment of Peripheral Arterial Disease Combining Fiber Optic RealShape Technology and Intravascular Ultrasound

Vascular surgeons and interventional radiologists face chronic exposure to low-dose radiation during endovascular procedures, which may impact their health in the long term due to their stochastic effects. The presented case shows the feasibility and efficacy of combining Fiber Optic RealShape (FORS) technology and intravascular ultrasound (IVUS) to reduce operator exposure during the endovascular treatment of obstructive peripheral arterial disease (PAD). 
FORS technology enables real-time, three-dimensional visualization of the full shape of guidewires and catheters, embedded with optical fibers that use laser light instead of fluoroscopy. Hereby, radiation exposure is reduced, and spatial perception is improved while navigating during endovascular procedures. IVUS has the capacity to optimally define vessel dimensions. Combining FORS and IVUS in a patient with iliac in-stent restenosis, as shown in this case report, enables passage of the stenosis and pre- and post-percutaneous transluminal angioplasty (PTA) plaque assessment (diameter improvement and morphology), with a minimum dose of radiation and zero contrast agent. The aim of this article is to describe the method of combining FORS and IVUS stepwise, to show the potential of merging both techniques in view of reducing radiation exposure and improving navigation tasks and treatment success during the endovascular procedure for the treatment of PAD.

Described here is a stepwise method of combining Fiber Optic RealShape technology and intravascular ultrasound to show the potential of merging both techniques, in view of the reduction of radiation exposure and improvement of navigation tasks and treatment success during an endovascular procedure for the treatment of peripheral arterial disease.

Vascular surgeons and interventional radiologists face chronic exposure to low-dose radiation during endovascular procedures, which may impact their ...

Optimized 3D Reconstruction and Motion Mapping for Remote AR-Assisted Surgery

Automatic Surgery in Transcatheter Aortic Valve Replacement Using Augmented Reality

Augmented Reality (AR) is in high demand in medical applications. The aim of the paper is to provide automatic surgery using AR for the Transcatheter Aortic Valve Replacement (TAVR). TAVR is the alternate medical procedure for open-heart surgery. TAVR replaces the injured valve with the new one using a catheter. In the existing model, remote guidance is given, while the surgery is not automated based on AR. In this article, we deployed a spatially aligned camera that is connected to a motor for the automation of image capture in the surgical environment. The camera tracks the 2D high-resolution image of the patient's heart along with the catheter testbed. These captured images are uploaded using the mobile app to a remote surgeon who is a cardiology expert. This image is utilized for the 3D reconstruction from 2D image tracking. This is viewed in a HoloLens like an emulator in a laptop. The surgeon can remotely inspect the 3D reconstructed images with additional transformation features such as rotation and scaling. These transformation features are enabled through hand gestures. The surgeon's guidance is transmitted to the surgical environment to automate the process in real-time scenarios. The catheter testbed in the surgical field is controlled by the hand gesture guidance of the remote surgeon. The developed prototype model demonstrates the effectiveness of remote surgical guidance through AR.

Author Spotlight: Revolutionizing Remote Surgery with Augmented Reality and Robotics for Enhanced Precision and Accessibility

This article presents the design and implementation of an automatic surgery module based on augmented reality (AR)- based 3D reconstruction. The system enables remote surgery by allowing surgeons to inspect reconstructed features and replicate surgical hand movements as if they were performing the surgery in close proximity.

Augmented Reality (AR) is in high demand in medical applications. The aim of the paper is to provide automatic surgery using AR for the Transcatheter ...

Improved Registration of 3D CT Angiography with X-ray Fluoroscopy for Image Fusion During Transcatheter Aortic Valve Implantation

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