Flow patterns in ascending aortic aneurysms: Determining the role of hypertension using phase contrast magnetic resonance and computational fluid dynamics

Thoracic aortic aneurysm (TAA) is a local dilation of the thoracic aorta. Although universally used, aneurysm diameter alone is a poor predictor of major complications such as rupture. There is a need for better biomarkers for risk assessment that also reflect the aberrant flow patterns found in TAAs. Furthermore, hypertension is often...

Modeling of blood flow in aorta: MRI-based computational fluid dynamics of aortic hemodynamics

Aortic aneurysm, a balloon-like enlargement of the healthy artery, is a cardiovascular disease with one of the highest mortality rates. These numbers are due to the usual late diagnosis of the aneurysm, which is often asymptomatic until a fatal event occurs. Such an event can progress to aortic dissection or rupture. Due to the urgent nature of...

Influence of aortic aneurysm on the local distribution of NO and O₂ using image-based computational fluid dynamics

There is a pressing need to establish novel biomarkers to predict the progression of thoracic aortic aneurysm (TAA) dilatation. Aside from hemodynamics, the roles of oxygen (O₂) and nitric oxide (NO) in TAA pathogenesis are potentially significant. As such, it is imperative to comprehend the relationship between aneurysm presence...

Hemodynamic Study of a Patient-Specific Intracranial Aneurysm: Comparative Assessment of Tomographic PIV, Stereoscopic PIV, In Vivo MRI and Computational Fluid Dynamics

Introduction: Wall shear stress (WSS) is associated with the growth and rupture of an intracranial aneurysm. To reveal their underlying connections, many image-based computational fluid dynamics (CFD) studies have been conducted. However, the methodological validations using both in vivo medical imaging and in vitro optical flow measurements...

Echo planar imaging–induced errors in intracardiac 4D flow MRI quantification

Purpose: To assess errors associated with EPI-accelerated intracardiac 4D flow MRI (4DEPI) with EPI factor 5, compared with non-EPI gradient echo (4DGRE). Methods: Three 3T MRI experiments were performed comparing 4DEPI to 4DGRE: steady flow through straight tubes, pulsatile flow in a left-ventricle phantom, and intracardiac flow in 10...

Retrospective Camera-Based Respiratory Gating in Clinical Whole-Heart 4D Flow MRI

Background: Respiratory gating is generally recommended in 4D flow MRI of the heart to avoid blurring and motion artifacts. Recently, a novel automated contact-less camera-based respiratory motion sensor has been introduced. Purpose: To compare camera-based respiratory gating (CAM) with liver-lung-navigator-based gating (NAV) and no gating ...