Impact of stent malapposition on intracoronary flow dynamics: an optical coherence tomography-based patient-specific study

2021 ◽  
Author(s):  
Lingling Wei ◽  
Jiaqiu Wang ◽  
Qiang Chen ◽  
Zhiyong Li
Keyword(s):  
Optical Coherence Tomography ◽  
Flow Dynamics ◽  
Patient Specific ◽  
Optical Coherence ◽  
Specific Study

Optical Coherence Tomography-Guided Retinal Prosthesis Design: Model of Degenerated Retinal Curvature and Thickness for Patient-Specific Devices

2014 ◽  
Vol 38 (6) ◽  
pp. E82-E94 ◽  
Author(s):  
Nicholas L. Opie ◽  
Lauren N. Ayton ◽  
Nicholas V. Apollo ◽  
Kumaravelu Ganesan ◽  
Robyn H. Guymer ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Retinal Prosthesis ◽  
Prosthesis Design ◽  
Design Model ◽  
Patient Specific ◽  
Optical Coherence

scholarly journals Combining IVUS and Optical Coherence Tomography for More Accurate Coronary Cap Thickness Quantification and Stress/Strain Calculations: A Patient-Specific Three-Dimensional Fluid-Structure Interaction Modeling Approach

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Xiaoya Guo ◽  
Don P. Giddens ◽  
David Molony ◽  
Chun Yang ◽  
Habib Samady ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Patient Specific ◽  
Data Sets ◽  
Optical Coherence ◽  
Stress Strain ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Modeling Approach

Accurate cap thickness and stress/strain quantifications are of fundamental importance for vulnerable plaque research. Virtual histology intravascular ultrasound (VH-IVUS) sets cap thickness to zero when cap is under resolution limit and IVUS does not see it. An innovative modeling approach combining IVUS and optical coherence tomography (OCT) is introduced for cap thickness quantification and more accurate cap stress/strain calculations. In vivo IVUS and OCT coronary plaque data were acquired with informed consent obtained. IVUS and OCT images were merged to form the IVUS + OCT data set, with biplane angiography providing three-dimensional (3D) vessel curvature. For components where VH-IVUS set zero cap thickness (i.e., no cap), a cap was added with minimum cap thickness set as 50 and 180 μm to generate IVUS50 and IVUS180 data sets for model construction, respectively. 3D fluid–structure interaction (FSI) models based on IVUS + OCT, IVUS50, and IVUS180 data sets were constructed to investigate cap thickness impact on stress/strain calculations. Compared to IVUS + OCT, IVUS50 underestimated mean cap thickness (27 slices) by 34.5%, overestimated mean cap stress by 45.8%, (96.4 versus 66.1 kPa). IVUS50 maximum cap stress was 59.2% higher than that from IVUS + OCT model (564.2 versus 354.5 kPa). Differences between IVUS and IVUS + OCT models for cap strain and flow shear stress (FSS) were modest (cap strain <12%; FSS <6%). IVUS + OCT data and models could provide more accurate cap thickness and stress/strain calculations which will serve as basis for further plaque investigations.

scholarly journals Development of an Intravascular Doppler Optical Coherence Tomography Imaging Technique for Neurovascular Applications

2021 ◽  
Author(s):  
Barry Vuong
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Intracranial Aneurysm ◽  
Intracranial Aneurysms ◽  
Fluid Dynamic ◽  
Patient Specific ◽  
Optical Coherence ◽  
Specific Flow ◽  
Arterial Lumen ◽  
Risk Of Rupture

The rupture of an intracranial aneurysm can cause spontaneous subarachnoid hemorrhage and result in sudden death. A large portion of intracranial aneurysms occurs near the center of the head, at the skull base, which poses significant technical challenge to neurosurgeons due to limited accessibility. The utilization of angiography is prominent during the treatment of intracranial aneurysms. However, malapposition of stent or incomplete packing of the intracranial aneurysm can be difficult to assess with angiography, and could lead to severe postoperative complications. As a result, angiography may not be sufficient in determining the risk of rupture as the compensatory mechanisms are known to occur at the microstructural level due to the local hemodynamics in the arterial lumen, as well as in evaluating the intraoperative treatment. In this work, we describe a method for assessing intracranial aneurysm through the evaluation of blood flow within the lumen and morphological structures of the arterial wall with optical coherence tomography (OCT). Sterile intravascular fiber-optic catheters can be introduced in the artery to detect blood flow. Prior to this work, limited investigations of catheter based Doppler OCT (DOCT) were reported. A novel signal processing technique was developed to further reduce the effect of Doppler noise within a catheter based DOCT system. This technique consisted of splitting the interferogram of an OCT signal prior to estimating the Doppler shift. This split spectrum DOCT (ssDOCT) method was evaluated through flow models and porcine models, as well as through the correlation between ssDOCT algorithm and computational fluid dynamic (CFD) models. It was observed that ssDOCT provided improved Doppler artefact suppression over the conventional DOCT technique. ssDOCT also provided the ability to estimate lower velocities within the DOCT image to measure the hemodynamic patterns around stent struts in both the internal carotid and patient specific flow phantoms. An OCT imaging study was also conducted consisting of surgically resected human intracranial aneurysms. Further enhancement of the detection of these key morphological structures was demonstrated by an optical-attenuation imaging variant of OCT. The presented techniques could provide further insights to the cause of intracranial aneurysm rupture and vascular healing mechanisms.

Optical Coherence Tomography-Based Patient-Specific Residual Multi-Thrombus Coronary Plaque Models with Fluid-Structure Interaction for Better Treatment Decisions: A Biomechanical Modeling Case Study

2021 ◽  
Author(s):  
Liang Wang ◽  
Luping He ◽  
Haibo Jia ◽  
Rui Lv ◽  
Xiaoya Guo ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Solid Mechanics ◽  
Treatment Plan ◽  
Specific Treatment ◽  
Coronary Plaque ◽  
Patient Specific ◽  
Optical Coherence ◽  
Aspiration Thrombectomy ◽  
Coronary Syndrome ◽  
Residual Thrombus

Abstract Intracoronary thrombus from plaque erosion could cause fatal acute coronary syndrome (ACS). A conservative anti-thrombotic therapy has been proposed to treat ACS patients in lieu of stenting. It is speculated that the residual thrombus after aspiration thrombectomy would influence the prognosis of this treatment. However, biomechanical mechanisms affecting intracoronary thrombus remodeling and clinical outcome remain largely unknown. In vivo optical coherence tomography (OCT) data of a coronary plaque with two residual thrombi after anti-thrombotic therapy were acquired from an ACS patient with consent obtained. Three OCT-based FSI models with different thrombus volumes, fluid-only and structure-only models were constructed to simulate and compare the biomechanical interplay among blood flow, residual thrombus and vessel wall mimicking different clinical situations. Our results showed that residual thrombus would decrease coronary volumetric flow rate by 9.3%, but elevate wall shear stress (WSS) by 29.4% and 75.5% at Thrombus 1 & 2, respectively. WSS variations in a cardiac cycle from structure-only model were 12.1% and 13.5% higher at the two thrombus surfaces than those from FSI model. Intracoronary thrombi were subjected to compressive forces indicated by negative thrombus stress. Tandem intracoronary thrombus might influence coronary hemodynamics and solid mechanics differently. Computational modeling could be used to quantify biomechanical conditions under which patients could receive patient-specific treatment plan with optimized outcome after anti-thrombotic therapy. More patient studies with follow-up data are needed to continue the investigation and better understand mechanisms governing thrombus remodeling process.

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