Emory cardiovascular imaging & biomechanics core laboratory

Angiography is the established imaging technique used routinely during all coronary diagnostic and interventional procedures. Angiograms are qualified as either single plane with one projection, single plane with two or more projections, or biplane. (Multiple projections are crucial for reconstructing heart vessels in 3-Dimensions). Angiographic projections are outlined at the bottom of the angiographic cines. Biplane angiograms are identified by consecutive cines with an equal number of frames and are preferred to single plane angiograms with multiple projections. If a case contains only single plane angiograms with one projection, then it is omitted from the study for not following protocol.

Intravascular Ultrasound (IVUS) is a technique providing cross-sectional, high-resolution tomographic images of the arterial wall. This technique yields qualitative and quantitative assessment of the extent and severity of arterial atherosclerotic diseases. Intravascular ultrasound (IVUS) pullbacks are qualified as either gray scale or virtual histology.

Optical Coherence Tomography (OCT), a light-based intravascular imaging modality, permits the in vivo visualization of biologic tissues with an unmatched resolution of 15 microns. Optical coherence tomography (OCT) pullbacks are screened for image clarity, ie. no skipping, clear defined lumen.

Once screened, data are stored both onsite in a username and password protected storage server and on Emory BOX (HIPAA compliant file sharing software) organized by case ID. Complete cases are chosen at random. The clinical division works to reconstruct the wire in 3 dimensions using Medis QAngio XA 3D Straight and Bifurcation (3D QCA software). Additionally, contours are added to IVUS pullbacks that outline both the vessel boundaries and the lumen boundaries using INDEC Echoplaque 4.0.27 (VH-IVUS software). IVUS and angiographic are co-registered using branch points along the vessel for reference. DAT,XML, and TIFF files of the IVUS pullback along with the Medis reconstructed wires are sent to the engineering division where computational fluid models of the vessels are created.

Computational fluid dynamic (CFD) simulations to calculate WSS values have been validated and used extensively in our laboratory. Following imaging and hemodynamic data acquisition, 3-dimensional (3D) coronary geometries are reconstructed and a mesh is created based on the geometry. A set of conditions (e.g., incompressible Newtonian fluid, pulsatile inlet velocity values applied at the inlet  face  as  a  series  of  axisymmetric  blunt  core profiles, traction-free boundary conditions applied at all outlets, and a no-slip boundary condition applied at the vessel wall) are employed in the finite volume method used for solving the Navier-Stokes equations. For OCT derived reconstructions, the wire is again reconstructed in 3 dimensions. OCT and the wire are also co-registered with branch points along the vessel and sent to the mathematical division to create the computational fluid dynamic models. 

Core lab members and contact information

Core Lab Principals

Habib Samady, MD, FACC

Professor of Medicine

Director, Interventional Cardiology
Emory University Hospitals Director
Emory Cardiovascular Imaging & Biomechanical Core Laboratory

Email: hsamady@emory.edu

Spencer B. King III, MD, MACC
Emeritus Professor of Medicine, Emory University School of Medicine
Email:Spencer.King@emoryhealthcare.org

Alessandro Veneziani, PhD
Associate Professor, Department of Mathematics & Computer Science
Email:avenez2@emory.edu

Don P. Giddens, PhD
Dean Emeritus - College of Engineering
Professor, Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory
Email:don.giddens@bme.gatech.edu

Core Lab Staff

Bll D. Gogas, MD, PHD, FACC  (Vasileios D. Gkogkas)
Instructor of Medicine, Division of Cardiology, Emory University School of Medicine
Email:vasileios.gkogkas@emory.edubgogas@gmail.com

Luke Timmins, PhD
Instructor, Department of Radiology and Imaging Sciences, Emory University School of Medicine
Email:lucas.timmins@bme.gatech.edu

Marina Piccinelli, PhD
Instructor, Department of Radiology and Imaging Sciences, Emory University School of Medicine
Email:marina.piccinelli@gmail.com

Olivia Y. Hung, MD, PhD
Cardiology Fellow, Emory University School of Medicine
Email:ohung@emory.edu

Parham Eshtehardi, MD 
Cardiology Fellow, Emory University School of Medicine
Email:parham.eshtehardi@emory.edu

David Molony, PhD
Post Doctoral Fellow, Emory University School of Medicine
Email:dmolony@emory.edu

Boyi Yang, MS, PhD
Post-Doctoral Fellow, Department of Mathematics & Computer Science
Email:yangboyi@gmail.com and byang8@emory.edu

Teresa Stilly, MBA
Manager, Research Projects
Email:teresa.stilley@emory.edu

Cardiology Research Interns

Yasir Bouchi, BS
Email:ybouchi@emory.edu

Udit Joshi, MD
Email:udit.joshi@emory.edu

Wenjie Zeng, MD, MPH
Email:wenjie.zeng@emory.edu

Faten Sebaali, BS, MS
Email:faten.sebaali@emory.edu

Visiting Scholars

Sung Ahn, MD
Jon Suh, M.D

Publications

Project 1 - Pre clinical research - Vascular Reparative Therapy

Vasomotor Function Comparative Assessment at 1-, 2-, 3-, and 4-years of Vessels Treated with the Absorb Everolimus- Eluting Bioresorbable Vascular Scaffold and the Xience V Everolimus-Eluting Metallic stent in Porcine Coronary Arteries.

Despite innovations in the field of coronary stenting, clinical restenosis and stent thrombosis rates following stent deployment in diseased coronary arterial segments remain 5.0% and 0.4%, respectively. Furthermore, late or very late clinical events attributed to in-stent neoatherosclerosis, very late stent thrombosis, and endothelial dysfunction are being increasingly observed. Permanent metallic drug-eluting stents (DES) with durable polymer coatings induce sustained endothelial- or non-endothelial dependent vasomotor dysfunction after revascularization both within and distal to the implanted segments which invariably extends during the healing phase. There is a paucity of experimental comparator observations assessing short- and long-term vascular responses following deployment of permanent metallic stents and fully resorbable scaffolds in the absence of underlying atherosclerosis. Accordingly we investigated the vasomotor and genetic responses of porcine coronary arteries treated with a permanent metallic DES, the Xience V (XV) stent (Abbott Vascular, Santa Clara, California), and a fully resorbable scaffold, the Absorb bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, California), at 1- and 2- years. We hypothesized that BVS treated coronary segments will demonstrate more robust functional and phenotypic recovery compared to XV treated vessels at 1-, 2-, 3- and 4-year follow-up.

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Project 2: Clinical research: ABSORB III Imaging sub-study

Evaluation and Comparison of Three-Dimensional Wall Shear Stress Patterns And Neointimal Healing Following Percutaneous Coronary Intervention With the Absorb Everolimus-Eluting Bioresorbable Vascular Scaffold Compared to the Xience V Everolimus-Eluting Metallic Stent.

To evaluate the effects of the fully bioresorbable stent system, Absorb everolimus-eluting bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, Calif. USA) and themetallic device: XIENCE everolimus eluting stent (Abbott Vascular, Santa Clara, Calif. USA) on the local hemodynamics and vessel compliance in subjects entered into the imaging sub-study of the ABSORB randomized clinical trial (ABSORB III) and prospectively correlate these biomechanical characteristics to clinical outcomes.

Samady 2

Project 3: Shear-Stent study

Conformability Assessment of Resolute Integrity Zotarolimus-Eluting Stent versus XIENCE Xpedition Everolimus-Eluting Stent

The aim of this study is to calculate OCT-derived WSS within R-ZES and X-EES stents and relate differences in regional in-stent WSS to neo-intimal tissue coverage assessed by OCT at one year and to calculate IVUS-derived WSS at the R-ZES and X-EES stent edges and relate differences in regional WSS at stent edges to change in plaque area at one year in patients undergoing PCI to angulated coronary arteries.

Samady