Toward Decision Support System for Lower Limb Endovascular Revascularization.

Vascular surgeons take decisions on the revascularization technics when surgery is needed for patients with Lower Extremities Arterial Disease (LEAD). This decision requires experience, good knowledge of official recommandations and new technics and an exhaustive description of the patient status. The Case Based Reasoning (CBR) is a good candidate to clinical decision support.

Computer-Assisted Transcatheter Mitral Valve Implantation for Valve-in-Valve Procedures.

Transcatheter mitral valve-in-valve is an alternative to high-risk reoperation on a failing bioprosthesis. It entails specific challenges such as left ventricular outflow tract obstruction. We propose a patient-specific augmented imaging based on preoperative planning to assist the procedure.

A parametric study assessing Implicit Solver limits for a generic FEM Simulation of PTA without stent deployment.

This study focuses on the robustness of a generic Finite Element Model (FEM) of Percutaneous Transluminal Angioplasty (PTA) procedure with permanent set. The influence of three different parameters on simulation robustness were investigated: the stenosis percent, the stenosis offset and the arterial caliber. Five arterial calibers are modeled by adapting the ratio between the inner diameter and the wall thickness.

Catheter navigation support for mechanical thrombectomy guidance: 3D/2D multimodal catheter-based registration with no contrast dye fluoroscopy.

Purpose: The fusion of pre-operative imaging and intra-operative fluoroscopy may support physicians during mechanical thrombectomy for catheter navigation from the aortic arch to carotids. Nevertheless, the aortic arch volume is too important for intra-operative contrast dye injection leading to a lack of common anatomical structure of interest that results in a challenging 3D/2D registration. The objective of this work is to propose a registration method between pre-operative 3D image and no contrast dye intra-operative fluoroscopy.

Assessment of shape-based features ability to predict the ascending aortic aneurysm growth.

The current guidelines for the ascending aortic aneurysm (AsAA) treatment recommend surgery mainly according to the maximum diameter assessment. This criterion has already proven to be often inefficient in identifying patients at high risk of aneurysm growth and rupture. In this study, we propose a method to compute a set of local shape features that, in addition to the maximum diameter , are intended to improve the classification performances for the ascending aortic aneurysm growth risk assessment.

Deep-learning approach to automate the segmentation of aorta in non-contrast CTs.

Purpose: Segmentation of vascular structures in preoperative computed tomography (CT) is a preliminary step for computer-assisted endovascular navigation. It is a challenging issue when contrast medium enhancement is reduced or impossible, as in the case of endovascular abdominal aneurysm repair for patients with severe renal impairment. In non-contrast-enhanced CTs, the segmentation tasks are currently hampered by the problems of low contrast, similar topological form, and size imbalance.

Patient-specific finite element simulation of peripheral artery percutaneous transluminal angioplasty to evaluate the procedure outcome without stent implantation.

The purpose of this work is to present a patient-specific (PS) modeling approach for simulating percutaneous transluminal angioplasty (PTA) endovascular treatment and assessing the balloon sizing influence on short-term outcomes in peripheral arteries, i.e. without stent implantation.

Statistical shape model of vessel centerline for endovascular paths comparison in mechanical thrombectomy.

Endovascular interventions are experiencing an important development. Despite many advantages of this type of intervention, catheter navigation is still a cause of difficulties or failure. Mechanical thrombectomy is one of these interventions where navigation difficulties are related to the ability to navigate the aortic arch and access the carotid.

Validation of a Whole Heart Segmentation from Computed Tomography Imaging Using a Deep-Learning Approach.

The aim of this study is to develop an automated deep-learning-based whole heart segmentation of ECG-gated computed tomography data. After 21 exclusions, CT acquired before transcatheter aortic valve implantation in 71 patients were reviewed and randomly split in a training (n = 55 patients), validation (n = 8 patients), and a test set (n = 8 patients). A fully automatic deep-learning method combining two convolutional neural networks performed segmentation of 10 cardiovascular structures, which was compared with the manually segmented reference by the Dice index.

Influence of balloon design, plaque material composition, and balloon sizing on acute post angioplasty outcomes: An implicit finite element analysis.

In this work we propose a generic modeling approach for simulating percutaneous transluminal angioplasty (PTA) endovascular treatment, and evaluating the influence of balloon design, plaque composition, and balloon sizing on acute post-procedural outcomes right after PTA, without stent implantation. Clinically-used PTA balloons were classified into two categories according to their compliance characteristics, and were modeled correspondingly. Self-defined elastoplastic constitutive laws were implemented within the plaque and artery models, after calibration based on experimental and clinical data.

Computer-assisted valve in valve in a deteriorated Mosaic valve using a library of bioprostheses.

Valve-in-valve (ViV) procedures have emerged from an off-label procedure to a safe and efficient alternative to redo aortic valve replacement in the treatment of symptomatic structural valve deterioration (SVD). During ViV procedures, optimal placement of the transcatheter heart valve (THV) inside the degenerated bioprosthesis is of paramount importance regarding complications such as device embolization, coronary obstruction, periprosthetic regurgitation, residual gradients, and mitral valve injury, but also for the attainment of optimal hemodynamics. In the case of the Mosaic (Medtronic, Minneapolis, MN) valve, the limited radiopaque landmarks represent a challenge to a reproducible, optimal implantation.

Numerical simulation of fenestrated graft deployment: Anticipation of stent graft and vascular structure adequacy.

Fenestrated endovascular aneurism repair (FEVAR) is a minimally invasive technique, and its success depends on the adequacy of the correspondence between the visceral arteries ostia and position of the fenestrations of the stent graft (SG) during its deployment in juxtarenal aneurisms. However, the fenestration position is generally determined from a preoperative computerised tomography (CT) scan, without considering the vascular deformation induced by the insertion of the endovascular tools. Catheterisation difficulties may occur during clinical procedures.

Planning With Patient-Specific Rectal Sub-Region Constraints Decreases Probability of Toxicity in Prostate Cancer Radiotherapy.

A rectal sub-region (SRR) has been previously identified by voxel-wise analysis in the inferior-anterior part of the rectum as highly predictive of rectal bleeding (RB) in prostate cancer radiotherapy. Translating the SRR to patient-specific radiotherapy planning is challenging as new constraints have to be defined. A recent geometry-based model proposed to optimize the planning by determining the achievable mean doses (AMDs) to the organs at risk (OARs), taking into account the overlap between the planning target volume (PTV) and OAR.

The influence of angioplasty balloon sizing on acute post-procedural outcomes: a Finite Element Analysis.

Atherosclerosis is one of the most common vascular pathologies in the world. Among the most commonly performed endovascular treatments, percutaneous transluminal angioplasty (PTA) has been showing significantly positive clinical outcomes. Due to the complex geometries, material properties and interactions that characterize PTA procedures, finite element analyses of acute angioplasty balloon deployment are limited.

Similarity measures and attribute selection for case-based reasoning in transcatheter aortic valve implantation.

In a clinical decision support system, the purpose of case-based reasoning is to help clinicians make convenient decisions for diagnoses or interventional gestures. Past experience, which is represented by a case-base of previous patients, is exploited to solve similar current problems using four steps-retrieve, reuse, revise, and retain. The proposed case-based reasoning has been focused on transcatheter aortic valve implantation to respond to clinical issues pertaining vascular access and prosthesis choices.

Catheter navigation support for liver radioembolization guidance: feasibility of structure-driven intensity-based registration.

Purpose: The fusion of pre/intraoperative images may improve catheter manipulation during radioembolization (RE) interventions by adding relevant information. The objective of this work is to propose and evaluate the performance of a RE guidance strategy relying on structure-driven intensity-based registration between preoperative CTA and intraoperative X-ray images.

Methods: The navigation strategy is decomposed into three image fusion steps, supporting the catheter navigation from the femoral artery till reaching the injection site (IS).

Patient-specific access planning in minimally invasive mitral valve surgery.

Background: Minimally invasive mitral valve repair or replacement (MIMVR) approaches have been increasingly adopted for the treatment of mitral regurgitation, allowing a shorter recovery time and improving postoperative quality of life. However, inadequate positioning of the right mini thoracotomy access (working port) translates into suboptimal exposure, prolonged operative times and, potentially, reduction in the quality of mitral repair. At present, we are missing tools to further improve the positioning of the working port in order to ameliorate surgical exposure in a patient- specific fashion.

Patient-specific and real-time model of numerical simulation of the hemodynamics of type B aortic dissections.

Introduction: Regular monitoring of uncomplicated type B aortic dissection is essential because 25-30% will progress to aneurysmal form. The predictive factors of this evolution are not clearly defined, but they seem to be correlated with hemodynamic data.

Hypothesis: Our goal is to create a patient-specific and real-time model of numerical simulation of the hemodynamics of uncomplicated type B aortic dissections in order to predict the evolution of these pathologies for earlier treatment.

Use of Numerical Simulation to Predict Iliac Complications During Placement of An Aortic Stent Graft.

Background: During endovascular aneurysm repair (EVAR), complex iliac anatomy is a source of complications such as unintentional coverage of the hypogastric artery. The aim of our study was to evaluate ability to predict coverage of the hypogastric artery using a biomechanical model simulating arterial deformations caused by the delivery system.

Methods: The biomechanical model of deformation has been validated by many publications.

Deformable image registration for radiation therapy: principle, methods, applications and evaluation.

Deformable image registration (DIR) is increasingly used in the field of radiation therapy (RT) to account for anatomical deformations. The aims of this paper are to describe the main applications of DIR in RT and discuss current DIR evaluation methods. Articles on DIR published from January 2000 to October 2018 were extracted from PubMed and Science Direct.

Structural valve deterioration does not alter tissue valves' radiopaque landmarks: Implications for valve-in-valve therapy.

Background: Valve-in-valve is established as a safe and efficient alternative to redo surgery in the treatment of structural valve deterioration (SVD). In vitro models rely on the radiopaque landmarks of undeteriorated tissue valves to establish the optimal implantation level of the transcatheter heart valves inside the deteriorated valves. In computed assisted procedures, the radiopaque landmarks of the deteriorated valves may be used to guide valve implantation through image fusion.

Deformable image registration for dose mapping between external beam radiotherapy and brachytherapy images of cervical cancer.

For locally advanced cervical cancer (LACC), anatomy correspondence with and without BT applicator needs to be quantified to merge the delivered doses of external beam radiation therapy (EBRT) and brachytherapy (BT). This study proposed and evaluated different deformable image registration (DIR) methods for this application. Twenty patients who underwent EBRT and BT for LACC were retrospectively analyzed.