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Sommer KN, Bhurwani MMS, Tutino V, Siddiqui A, Davies J, Snyder K, Levy E, Mokin M, Ionita CN. Use of patient specific 3D printed neurovascular phantoms to simulate mechanical thrombectomy. 3D Print Med 2021; 7:32. [PMID: 34568987 PMCID: PMC8474770 DOI: 10.1186/s41205-021-00122-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 09/11/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND The ability of the patient specific 3D printed neurovascular phantoms to accurately replicate the anatomy and hemodynamics of the chronic neurovascular diseases has been demonstrated by many studies. Acute occurrences, however, may still require further development and investigation and therefore we studied acute ischemic stroke (AIS). The efficacy of endovascular procedures such as mechanical thrombectomy (MT) for the treatment of large vessel occlusion (LVO), can be improved by testing the performance of thrombectomy devices and techniques using patient specific 3D printed neurovascular models. METHODS 3D printed phantoms were connected to a flow loop with physiologically relevant flow conditions, including input flow rate and fluid temperature. A simulated blood clot was introduced into the model and placed in the proximal Middle Cerebral Artery (MCA) region. Clot location, composition, length, and arterial angulation were varied and MTs were simulated using stent retrievers. Device placement relative to the clot and the outcome of the thrombectomy were recorded for each situation. Digital subtraction angiograms (DSA) were captured before and after LVO simulation. Recanalization outcome was evaluated using DSA as either 'no recanalization' or 'recanalization'. Forty-two 3DP neurovascular phantom benchtop experiments were performed. RESULTS Clot angulation within the MCA region had the most significant impact on the MT outcome, with a p-value of 0.016. Other factors such as clot location, clot composition, and clot length correlated weakly with the MT outcome. CONCLUSIONS This project allowed us to gain knowledge of how such characteristics influence thrombectomy success and can be used in making clinical decisions when planning the procedure and selecting specific thrombectomy tools and approaches.
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Affiliation(s)
- Kelsey N. Sommer
- grid.273335.30000 0004 1936 9887Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228 USA ,grid.273335.30000 0004 1936 9887Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14208 USA
| | - Mohammad Mahdi Shiraz Bhurwani
- grid.273335.30000 0004 1936 9887Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228 USA ,grid.273335.30000 0004 1936 9887Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14208 USA
| | - Vincent Tutino
- grid.273335.30000 0004 1936 9887Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14208 USA ,grid.273335.30000 0004 1936 9887Department of Neurosurgery, University at Buffalo, Buffalo, NY 14208 USA ,grid.273335.30000 0004 1936 9887Department of Pathology and Anatomical Sciences, University at Buffalo, Buffalo, 14208 USA
| | - Adnan Siddiqui
- grid.273335.30000 0004 1936 9887Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14208 USA ,grid.273335.30000 0004 1936 9887Department of Neurosurgery, University at Buffalo, Buffalo, NY 14208 USA
| | - Jason Davies
- grid.273335.30000 0004 1936 9887Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14208 USA ,grid.273335.30000 0004 1936 9887Department of Neurosurgery, University at Buffalo, Buffalo, NY 14208 USA ,grid.273335.30000 0004 1936 9887Department of Biomedical Informatics, University at Buffalo, Buffalo, 14208 USA
| | - Kenneth Snyder
- grid.273335.30000 0004 1936 9887Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14208 USA ,grid.273335.30000 0004 1936 9887Department of Neurosurgery, University at Buffalo, Buffalo, NY 14208 USA
| | - Elad Levy
- grid.273335.30000 0004 1936 9887Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14208 USA ,grid.273335.30000 0004 1936 9887Department of Neurosurgery, University at Buffalo, Buffalo, NY 14208 USA
| | - Maxim Mokin
- grid.170693.a0000 0001 2353 285XDepartment of Neurosurgery and Brain Repair, University of South Florida, Tampa, FL 33620 USA
| | - Ciprian N. Ionita
- grid.273335.30000 0004 1936 9887Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228 USA ,grid.273335.30000 0004 1936 9887Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14208 USA ,grid.273335.30000 0004 1936 9887Department of Neurosurgery, University at Buffalo, Buffalo, NY 14208 USA
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Sommer KN, Iyer V, Kumamaru KK, Rava RA, Ionita CN. Method to simulate distal flow resistance in coronary arteries in 3D printed patient specific coronary models. 3D Print Med 2020; 6:19. [PMID: 32761497 PMCID: PMC7410153 DOI: 10.1186/s41205-020-00072-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/24/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Three-dimensional printing (3DP) offers a unique opportunity to build flexible vascular patient-specific coronary models for device testing, treatment planning, and physiological simulations. By optimizing the 3DP design to replicate the geometrical and mechanical properties of healthy and diseased arteries, we may improve the relevance of using such models to simulate the hemodynamics of coronary disease. We developed a method to build 3DP patient specific coronary phantoms, which maintain a significant part of the coronary tree, while preserving geometrical accuracy of the atherosclerotic plaques and allows for an adjustable hydraulic resistance. METHODS Coronary computed tomography angiography (CCTA) data was used within Vitrea (Vital Images, Minnetonka, MN) cardiac analysis application for automatic segmentation of the aortic root, Left Anterior Descending (LAD), Left Circumflex (LCX), Right Coronary Artery (RCA), and calcifications. Stereolithographic (STL) files of the vasculature and calcium were imported into Autodesk Meshmixer for 3D model optimization. A base with three chambers was built and interfaced with the phantom to allow fluid collection and independent distal resistance adjustment of the RCA, LAD and LCX and branching arteries. For the 3DP we used Agilus for the arterial wall, VeroClear for the base and a Vero blend for the calcifications, respectively. Each chamber outlet allowed interface with catheters of varying lengths and diameters for simulation of hydraulic resistance of both normal and hyperemic coronary flow conditions. To demonstrate the manufacturing approach appropriateness, models were tested in flow experiments. RESULTS Models were used successfully in flow experiments to simulate normal and hyperemic flow conditions. The inherent mean resistance of the chamber for the LAD, LCX, and RCA, were 1671, 1820, and 591 (dynes ∙ sec/ cm5), respectively. This was negligible when compared with estimates in humans, with the chamber resistance equating to 0.65-5.86%, 1.23-6.86%, and 0.05-1.67% of the coronary resistance for the LAD, LCX, and RCA, respectively at varying flow rates and activity states. Therefore, the chamber served as a means to simulate the compliance of the distal coronary trees and to allow facile coupling with a set of known resistance catheters to simulate various physical activity levels. CONCLUSIONS We have developed a method to create complex 3D printed patient specific coronary models derived from CCTA, which allow adjustable distal capillary bed resistances. This manufacturing approach permits comprehensive coronary model development which may be used for physiologically relevant flow simulations.
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Affiliation(s)
- Kelsey N Sommer
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, USA
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, USA
| | - Vijay Iyer
- University at Buffalo Cardiology, University at Buffalo Jacobs School of Medicine, Buffalo, NY, USA
| | | | - Ryan A Rava
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, USA
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, USA
| | - Ciprian N Ionita
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, USA.
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, USA.
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Abstract
Medical 3-dimensional (3D) printing is emerging as a clinically relevant imaging tool in directing preoperative and intraoperative planning in many surgical specialties and will therefore likely lead to interdisciplinary collaboration between engineers, radiologists, and surgeons. Data from standard imaging modalities such as computed tomography, magnetic resonance imaging, echocardiography, and rotational angiography can be used to fabricate life-sized models of human anatomy and pathology, as well as patient-specific implants and surgical guides. Cardiovascular 3D-printed models can improve diagnosis and allow for advanced preoperative planning. The majority of applications reported involve congenital heart diseases and valvular and great vessels pathologies. Printed models are suitable for planning both surgical and minimally invasive procedures. Added value has been reported toward improving outcomes, minimizing perioperative risk, and developing new procedures such as transcatheter mitral valve replacements. Similarly, thoracic surgeons are using 3D printing to assess invasion of vital structures by tumors and to assist in diagnosis and treatment of upper and lower airway diseases. Anatomic models enable surgeons to assimilate information more quickly than image review, choose the optimal surgical approach, and achieve surgery in a shorter time. Patient-specific 3D-printed implants are beginning to appear and may have significant impact on cosmetic and life-saving procedures in the future. In summary, cardiothoracic 3D printing is rapidly evolving and may be a potential game-changer for surgeons. The imager who is equipped with the tools to apply this new imaging science to cardiothoracic care is thus ideally positioned to innovate in this new emerging imaging modality.
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Sommer K, Izzo RL, Shepard L, Podgorsak AR, Rudin S, Siddiqui AH, Wilson MF, Angel E, Said Z, Springer M, Ionita CN. Design Optimization for Accurate Flow Simulations in 3D Printed Vascular Phantoms Derived from Computed Tomography Angiography. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2017; 10138. [PMID: 28663663 DOI: 10.1117/12.2253711] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
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.
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Affiliation(s)
- Kelsey Sommer
- Department of Biomedical Engineering, University at Buffalo, Buffalo NY 14228.,Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo NY 14208
| | - Richard L Izzo
- Department of Biomedical Engineering, University at Buffalo, Buffalo NY 14228.,Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo NY 14208.,The Jacobs Institute, Buffalo NY 14208
| | - Lauren Shepard
- Department of Biomedical Engineering, University at Buffalo, Buffalo NY 14228.,Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo NY 14208
| | - Alexander R Podgorsak
- Department of Biomedical Engineering, University at Buffalo, Buffalo NY 14228.,Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo NY 14208
| | - Stephen Rudin
- Department of Biomedical Engineering, University at Buffalo, Buffalo NY 14228.,Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo NY 14208.,University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo NY 14208
| | - Adnan H Siddiqui
- Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo NY 14208.,University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo NY 14208
| | - Michael F Wilson
- Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo NY 14208.,University at Buffalo Cardiology, University at Buffalo Jacobs School of Medicine, Buffalo NY 14208
| | - Erin Angel
- Toshiba America Medical Systems, Irvine CA 92618
| | - Zaid Said
- University at Buffalo Cardiology, University at Buffalo Jacobs School of Medicine, Buffalo NY 14208
| | | | - Ciprian N Ionita
- Department of Biomedical Engineering, University at Buffalo, Buffalo NY 14228.,Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo NY 14208.,University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo NY 14208
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Abstract
3D-printed models fabricated from CT, MRI, or echocardiography data provide the advantage of haptic feedback, direct manipulation, and enhanced understanding of cardiovascular anatomy and underlying pathologies. Reported applications of cardiovascular 3D printing span from diagnostic assistance and optimization of management algorithms in complex cardiovascular diseases, to planning and simulating surgical and interventional procedures. The technology has been used in practically the entire range of structural, valvular, and congenital heart diseases, and the added-value of 3D printing is established. Patient-specific implants and custom-made devices can be designed, produced, and tested, thus opening new horizons in personalized patient care and cardiovascular research. Physicians and trainees can better elucidate anatomical abnormalities with the use of 3D-printed models, and communication with patients is markedly improved. Cardiovascular 3D bioprinting and molecular 3D printing, although currently not translated into clinical practice, hold revolutionary potential. 3D printing is expected to have a broad influence in cardiovascular care, and will prove pivotal for the future generation of cardiovascular imagers and care providers. In this Review, we summarize the cardiovascular 3D printing workflow, from image acquisition to the generation of a hand-held model, and discuss the cardiovascular applications and the current status and future perspectives of cardiovascular 3D printing.
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Balasubramoniam A, Bednarek DR, Rudin S, Ionita CN. Sensitivity evaluation of DSA-based parametric imaging using Doppler ultrasound in neurovascular phantoms. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2016. [PMID: 28649163 DOI: 10.1117/12.2216907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
An evaluation of the relation between parametric imaging results obtained from Digital Subtraction Angiography (DSA) images and blood-flow velocity measured using Doppler ultrasound in patient-specific neurovascular phantoms is provided. A silicone neurovascular phantom containing internal carotid artery, middle cerebral artery and anterior communicating artery was embedded in a tissue equivalent gel. The gel prevented movement of the vessels when blood mimicking fluid was pumped through it to obtain Colour Doppler images. The phantom was connected to a peristaltic pump, simulating physiological flow conditions. To obtain the parametric images, water was pumped through the phantom at various flow rates (100, 120 and 160 ml/min) and 10 ml contrast boluses were injected. DSA images were obtained at 10 frames/sec from the Toshiba C-arm and DSA image sequences were input into LabVIEW software to get parametric maps from time-density curves. The parametric maps were compared with velocities determined by Doppler ultrasound at the internal carotid artery. The velocities measured by the Doppler ultrasound were 38, 48 and 65 cm/s for flow rates of 100, 120 and 160 ml/min, respectively. For the 20% increase in flow rate, the percentage change of blood velocity measured by Doppler ultrasound was 26.3%. Correspondingly, there was a 20% decrease of Bolus Arrival Time (BAT) and 14.3% decrease of Mean Transit Time (MTT), showing strong inverse correlation with Doppler measured velocity. The parametric imaging parameters are quite sensitive to velocity changes and are well correlated to the velocities measured by Doppler ultrasound.
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Affiliation(s)
- A Balasubramoniam
- Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14214
| | - D R Bednarek
- Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14214
| | - S Rudin
- Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14214
| | - C N Ionita
- Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14214
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Russ M, O'Hara R, Setlur Nagesh SV, Mokin M, Jimenez C, Siddiqui A, Bednarek D, Rudin S, Ionita C. Treatment Planning for Image-Guided Neuro-Vascular Interventions Using Patient-Specific 3D Printed Phantoms. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2015; 9417. [PMID: 26778878 DOI: 10.1117/12.2081997] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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.
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Affiliation(s)
- M Russ
- Toshiba Stroke and Vascular Research Center, University of Buffalo, Buffalo, NY
| | - R O'Hara
- Toshiba Stroke and Vascular Research Center, University of Buffalo, Buffalo, NY
| | - S V Setlur Nagesh
- Toshiba Stroke and Vascular Research Center, University of Buffalo, Buffalo, NY
| | - M Mokin
- Toshiba Stroke and Vascular Research Center, University of Buffalo, Buffalo, NY
| | - C Jimenez
- Toshiba Stroke and Vascular Research Center, University of Buffalo, Buffalo, NY; University of Antioquia-GIB-Eafit, Medellin, Colombia
| | - A Siddiqui
- Toshiba Stroke and Vascular Research Center, University of Buffalo, Buffalo, NY
| | - D Bednarek
- Toshiba Stroke and Vascular Research Center, University of Buffalo, Buffalo, NY
| | - S Rudin
- Toshiba Stroke and Vascular Research Center, University of Buffalo, Buffalo, NY
| | - C Ionita
- Toshiba Stroke and Vascular Research Center, University of Buffalo, Buffalo, NY
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Ionita CN, Mokin M, Varble N, Bednarek DR, Xiang J, Snyder KV, Siddiqui AH, Levy EI, Meng H, Rudin S. Challenges and limitations of patient-specific vascular phantom fabrication using 3D Polyjet printing. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2014; 9038:90380M. [PMID: 25300886 DOI: 10.1117/12.2042266] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Additive manufacturing (3D printing) technology offers a great opportunity towards development of patient-specific vascular anatomic models, for medical device testing and physiological condition evaluation. However, the development process is not yet well established and there are various limitations depending on the printing materials, the technology and the printer resolution. Patient-specific neuro-vascular anatomy was acquired from computed tomography angiography and rotational digital subtraction angiography (DSA). The volumes were imported into a Vitrea 3D workstation (Vital Images Inc.) and the vascular lumen of various vessels and pathologies were segmented using a "marching cubes" algorithm. The results were exported as Stereo Lithographic (STL) files and were further processed by smoothing, trimming, and wall extrusion (to add a custom wall to the model). The models were printed using a Polyjet printer, Eden 260V (Objet-Stratasys). To verify the phantom geometry accuracy, the phantom was reimaged using rotational DSA, and the new data was compared with the initial patient data. The most challenging part of the phantom manufacturing was removal of support material. This aspect could be a serious hurdle in building very tortuous phantoms or small vessels. The accuracy of the printed models was very good: distance analysis showed average differences of 120 μm between the patient and the phantom reconstructed volume dimensions. Most errors were due to residual support material left in the lumen of the phantom. Despite the post-printing challenges experienced during the support cleaning, this technology could be a tremendous benefit to medical research such as in device development and testing.
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Affiliation(s)
- Ciprian N Ionita
- Dept. of Biomedical Engineering, State University of New York at Buffalo ; Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Maxim Mokin
- Dept. of Neurosurgery, State University of New York at Buffalo
| | - Nicole Varble
- Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Daniel R Bednarek
- Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Jianping Xiang
- Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Kenneth V Snyder
- Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Adnan H Siddiqui
- Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Elad I Levy
- Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Hui Meng
- Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Stephen Rudin
- Dept. of Biomedical Engineering, State University of New York at Buffalo ; Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
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Ionita CN, Garcia VL, Bednarek DR, Snyder KV, Siddiqui AH, Levy EI, Rudin S. Effect of injection technique on temporal parametric imaging derived from digital subtraction angiography in patient specific phantoms. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2014; 9038:90380L. [PMID: 25302010 DOI: 10.1117/12.2041347] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Parametric imaging maps (PIM's) derived from digital subtraction angiography (DSA) for the cerebral arterial flow assessment in clinical settings have been proposed, but experiments have yet to determine the reliability of such studies. For this study, we have observed the effects of different injection techniques on PIM's. A flow circuit set to physiologic conditions was created using an internal carotid artery phantom. PIM's were derived for two catheter positions, two different contrast bolus injection volumes (5ml and 10 ml), and four injection rates (5, 10, 15 and 20 ml/s). Using a gamma variate fitting approach, we derived PIM's for mean-transit-time (MTT), time-to-peak (TTP) and bolus-arrivaltime (BAT). For the same injection rates, a larger bolus resulted in an increased MTT and TTP, while a faster injection rate resulted in a shorter MTT, TTP, and BAT. In addition, the position of the catheter tip within the vasculature directly affected the PIM. The experiment showed that the PIM is strongly correlated with the injection conditions, and, therefore, they have to be interpreted with caution. PIM images must be taken from the same patient to be able to be meaningfully compared. These comparisons can include pre- and post-treatment images taken immediately before and after an interventional procedure or simultaneous arterial flow comparisons through the left and right cerebral hemispheres. Due to the strong correlation between PIM and injection conditions, this study indicates that this assessment method should be used only to compare flow changes before and after treatment within the same patient using the same injection conditions.
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Affiliation(s)
- Ciprian N Ionita
- Dept. of Biomedical Engineering, State University of New York at Buffalo ; Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Victor L Garcia
- Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Daniel R Bednarek
- Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Kenneth V Snyder
- Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Adnan H Siddiqui
- Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Elad I Levy
- Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
| | - Stephen Rudin
- Dept. of Biomedical Engineering, State University of New York at Buffalo ; Dept. of Neurosurgery, State University of New York at Buffalo ; Toshiba Stroke and Vascular Research Center, State University of New York at Buffalo
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Ionita CN, Bednarek DR, Rudin S. Investigation of metrics to assess vascular flow modifications for diverter device designs using hydrodynamics and angiographic studies. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2012; 8317:83170F. [PMID: 24027624 DOI: 10.1117/12.915675] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Intracranial aneurysm treatment with flow diverters (FD) is a new minimally invasive approach, recently approved for use in human patients. Attempts to correlate the flow reduction observed in angiograms with a parameter related to the FD structure have not been totally successful. To find the proper parameter, we investigated four porous-media flow models. The models describing the relation between the pressure drop and flow velocity that are investigated include the capillary theory linear model (CTLM), the drag force linear model (DFLM), the simple quadratic model (SQM) and the modified quadratic model (MQM). Proportionality parameters are referred to as permeability for the linear models and resistance for the quadratic ones. A two stage experiment was performed. First, we verified flow model validity by placing six different stainless-steel meshes, resembling FD structures, in known flow conditions. The best flow model was used for the second stage, where six different FD's were inserted in aneurysm phantoms and flow modification was estimated using angiographically derived time density curves (TDC). Finally, TDC peak variation was compared with the FD parameter. Model validity experiments indicated errors of: 70% for the linear models, 26% for the SQM and 7% for the MQM. The resistance calculated according to the MQM model correlated well with the contrast flow reduction. Results indicate that resistance calculated according to MQM is appropriate to characterize the FD and could explain the flow modification observed in angiograms.
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Affiliation(s)
- Ciprian N Ionita
- State University of New York at Buffalo, Toshiba Stroke Research Center, 3435 Main St., Buffalo, NY 14214, USA
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Ionita CN, Natarajan SK, Wang W, Hopkins LN, Levy EI, Siddiqui AH, Bednarek DR, Rudin S. Evaluation of a second-generation self-expanding variable-porosity flow diverter in a rabbit elastase aneurysm model. AJNR Am J Neuroradiol 2011; 32:1399-407. [PMID: 21757527 DOI: 10.3174/ajnr.a2548] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The self-expanding V-POD is a second-generation flow-diverting device with a low-porosity PTFE patch on a self-expanding microstent. The authors evaluated this device for the treatment of elastase-induced aneurysms in rabbits. MATERIALS AND METHODS Three V-POD types (A, circumferential patch closed-cell stent [n = 9]; B, asymmetric patch closed-cell stent [n = 7]; and C, asymmetric patch open-cell stent [n = 4]) were evaluated by using angiography, conebeam micro-CT, histology, and SEM. Aneurysm flow modifications were expressed in terms of immediate poststent/prestent ratios of maximum CA volume entering the aneurysm dome tracked on procedural angiograms. Flow modifications were correlated with 4 weeks' follow-up angiographic, micro-CT, histologic, and SEM results. RESULTS Mechanical stent-deployment difficulties in 4 aneurysms (1 type A; 3 type B) led to suboptimal results and exclusion from analysis. Of the remaining 16 aneurysms, 4-week post-treatment angiograms showed no aneurysm filling in 10 (63%), 3 (∼19%) had no filling with a small remnant neck, and 3 (∼19%) had <0.25 filling. Successfully treated aneurysms (n = 16) demonstrated an immediate poststent/prestent CA maximum volume ratio of 0.13 ± 0.18% (0.0%-0.5%). Favorable contrast-flow modification on immediate angiography after deployment correlated significantly with aneurysm occlusion on follow-up angiography, micro-CT, and histology. The occlusion percentage derived from micro-CT was 96 ± 6.8%. Histology indicated advanced healing (grade ≥3) in the aneurysm dome in 13 of 16 cases. SEM revealed 15 of 16 stents in an advanced state of endothelialization. CONCLUSIONS This study showed the feasibility and effectiveness of V-POD for aneurysm healing in a rabbit elastase model.
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Affiliation(s)
- C N Ionita
- Department of Radiology, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, USA
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