4D Flow MRI of the Thoracic Aorta.

Four-dimensional (4D) flow MRI has emerged as a versatile technique for the three-dimensional evaluation of blood flow dynamics, offering the ability to visualize flow patterns qualitatively and allow for the retrospective quantification of standard and advanced hemodynamic parameters. Recent advancements in 4D flow MRI technology, including optimized acquisition protocols and improved hemodynamic analysis workflow efficiency, have facilitated its integration into standard clinical practice, enhancing the accessibility and applicability of this innovative imaging modality. A growing body of studies have demonstrated its clinical value for monitoring and informing the management of aortic pathologies, cementing its role in modern cardiovascular care.

Anatomy-derived 3D Aortic Hemodynamics Using Fluid Physics-informed Deep Learning.

Background Four-dimensional (4D) flow MRI provides assessment of thoracic aorta hemodynamic measures that are increasingly recognized as important biomarkers for risk assessment. However, long acquisition times and cumbersome data analysis limit widespread availability. Purpose To evaluate the feasibility and accuracy of a generative artificial intelligence (AI) approach (fluid physics-informed cycle generative adversarial network [FPI-CycleGAN]) in quantifying aorta hemodynamics directly from anatomic input as an alternative to 4D flow MRI.

Robustness of 4D flow MRI derived aortic wall shear stress and pulse wave velocity across different protocols in healthy controls and in patients with bicuspid aortic valve.

Purpose: To evaluate the reproducibility of important biomarkers like wall shear stress (WSS), pulse wave velocity (PWV), and net flow across two 4D flow MRI imaging protocols with different coverages: aorta-targeted 4D flow MRI (AT4D) and whole-heart 4D flow (WH4D) protocols.

Methods: Thirty-eight control subjects (43.2 ± 10.

Factors affecting radiation dose, radiation exposure time and procedural time in arterial embolization for active hemorrhage.

Purpose: To evaluate patient and procedure-related factors contributing to the radiation dose, cumulative fluoroscopy time (CFT), and procedural time (PT) of Arterial Embolization (AE) for suspected active bleeding.

Methods: Data on patients who underwent AE for suspected bleeding was retrospectively gathered between January 2019 and April 2022. Data collected included the dependent variables consisting of dose-area product (DAP), CFT, PT, and independent variables consisting of demographic, bleeding-specific, and procedure-specific parameters.

Clinical Applications of Four-Dimensional Flow MRI.

Four-dimensional flow MRI is a powerful phase contrast technique used for assessing three-dimensional (3D) blood flow dynamics. By acquiring a time-resolved velocity field, it enables flexible retrospective analysis of blood flow that can include qualitative 3D visualization of complex flow patterns, comprehensive assessment of multiple vessels, reliable placement of analysis planes, and calculation of advanced hemodynamic parameters. This technique provides several advantages over routine two-dimensional flow imaging techniques, allowing it to become part of clinical practice at major academic medical centers.