title: 4D flow MRI.
abstract: Traditionally, magnetic resonance imaging (MRI) of flow using phase contrast (PC) methods is accomplished using methods that resolve single-directional flow in two spatial dimensions (2D) of an individual slice. More recently, three-dimensional (3D) spatial encoding combined with three-directional velocity-encoded phase contrast MRI (here termed 4D flow MRI) has drawn increased attention. 4D flow MRI offers the ability to measure and to visualize the temporal evolution of complex blood flow patterns within an acquired 3D volume. Various methodological improvements permit the acquisition of 4D flow MRI data encompassing individual vascular structures and entire vascular territories such as the heart, the adjacent aorta, the carotid arteries, abdominal, or peripheral vessels within reasonable scan times. To subsequently analyze the flow data by quantitative means and visualization of complex, three-directional blood flow patterns, various tools have been proposed. This review intends to introduce currently used 4D flow MRI methods, including Cartesian and radial data acquisition, approaches for accelerated data acquisition, cardiac gating, and respiration control. Based on these developments, an overview is provided over the potential this new imaging technique has in different parts of the body from the head to the peripheral arteries.
authors.affiliation: Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA. mmarkl@northwestern.edu
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
authors.forename: Alex
authors.initials: A
authors.lastname: Frydrychowicz
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kozerke
authors.forename: Mike
authors.initials: M
authors.lastname: Hope
authors.forename: Oliver
authors.initials: O
authors.lastname: Wieben
mesh_terms: D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D002318:Cardiovascular Diseases / Q000175:diagnosis*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity