Publications by authors named "Mohamed Elhaddad"

Intraoperative image-guidance provides enhanced feedback that facilitates surgical decision-making in a wide variety of medical fields and is especially useful when haptic feedback is limited. In these cases, automated instrument-tracking and localization are essential to guide surgical maneuvers and prevent damage to underlying tissue. However, instrument-tracking is challenging and often confounded by variations in the surgical environment, resulting in a trade-off between accuracy and speed.

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Optical coherence tomography (OCT) is the gold standard for quantitative ophthalmic imaging. The majority of commercial and research systems require patients to fixate and be imaged in a seated upright position, which limits the ability to perform ophthalmic imaging in bedridden or pediatric patients. Handheld OCT devices overcome this limitation, but image quality often suffers due to a lack of real-time aiming and patient eye and photographer motion.

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Advances in microscopy have enabled us to see at unprecedented depths and resolutions, even breaking the diffraction-limit by several fold. These improvements have come at the expense of system complexity with microscopes routinely employing multiple objective lenses and custom optical relays. Optimal system design is paramount for imaging performance, but research systems are limited by the use of commercial components because optical prescriptions are often inaccessible.

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This work presents a numerical discretization technique for solving 3-dimensional material interface problems involving complex geometry without conforming mesh generation. The finite cell method (FCM), which is a high-order fictitious domain approach, is used for the numerical approximation of the solution without a boundary-conforming mesh. Weak discontinuities at material interfaces are resolved by using separate FCM meshes for each material sub-domain and weakly enforcing the interface conditions between the different meshes.

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Non-invasive biological imaging is crucial for understanding in vivo structure and function. Optical coherence tomography (OCT) and reflectance confocal microscopy are two of the most widely used optical modalities for exogenous contrast-free, high-resolution, three-dimensional imaging in non-fluorescent scattering tissues. However, sample motion remains a critical barrier to raster-scanned acquisition and reconstruction of wide-field anatomically accurate volumetric datasets.

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This study aims to determine the safety and efficacy of complete versus staged-percutaneous coronary intervention (PCI) of nonculprit lesions at the time of primary PCI in patients with multivessel disease. Recent trials had suggested that revascularization of nonculprit lesions at the time of primary PCI is associated with better outcomes, however; the optimum timing and overall safety of this approach is not well known. An observational prospective study was conducted, including 50 patients who presented with ST-segment elevation myocardial infarction and found to have at least an additional nonculprit significant (> 70%) type A or B lesion.

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Scanning laser ophthalmoscopy (SLO) benefits diagnostic imaging and therapeutic guidance by allowing for high-speed imaging of retinal structures. When combined with optical coherence tomography (OCT), SLO enables real-time aiming and retinal tracking and provides complementary information for post-acquisition volumetric co-registration, bulk motion compensation, and averaging. However, multimodality SLO-OCT systems generally require dedicated light sources, scanners, relay optics, detectors, and additional digitization and synchronization electronics, which increase system complexity.

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Microscope-integrated intraoperative OCT (iOCT) enables imaging of tissue cross-sections concurrent with ophthalmic surgical maneuvers. However, limited acquisition rates and complex three-dimensional visualization methods preclude real-time surgical guidance using iOCT. We present an automated stereo vision surgical instrument tracking system integrated with a prototype iOCT system.

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Atrial fibrillation occurs in 5-40% patients after coronary artery bypass graft surgery. Atrial fibrillation increases mortality and morbidity in the post-operative period. We sought to conduct a comprehensive review of literature focusing on pathophysiology, risk factors, prevention and treatment of post coronary artery bypass graft atrial fibrillation.

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Coronary CT angiography is an effective, evidence-based strategy for evaluating acute chest pain in the emergency department for patients at low-to-intermediate risk of acute coronary syndrome. Recent multicenter trials have reported that coronary CT angiography is safe, reduces time to diagnosis, facilitates discharge, and may lower overall cost compared with routine care. Herein, we provide a 10-step approach for establishing a successful coronary CT angiography program in the emergency department.

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Background: Elective percutaneous coronary intervention (PCI) is associated with myocardial necrosis, as evidenced by troponin release, in approximately one-third of cases. This is known to be linked with subsequent cardiovascular events. This study assessed the ability of remote ischemic preconditioning (RIPC) to attenuate cardiac troponin T (cTnT) release after elective PCI.

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Background And Objective: Atrial fibrillation (AF) is a common complication of cardiothoracic surgery (CTS). Existing evidence about the potential protective role of angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) for post-CTS AF has been limited and conflicting. In this single-blind, open-label, randomized prospective pilot study, we evaluated the potential protective role of irbesartan (an ARB) in post-coronary artery bypass graft (CABG) AF.

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