title: High temporal and high spatial resolution MR angiography (4D-MRA).
abstract: In the first decade of the twenty-first century, whole-body magnetic resonance scanners with high field strengths (and thus potentially better signal-to-noise ratios) were developed. At the same time, parallel imaging and "echo-sharing" techniques were refined to allow for increasingly high spatial and temporal resolution in dynamic magnetic resonance angiography ("time-resolved" = TR-MRA). This technological progress facilitated tracking the passage of intra-venously administered contrast agent boluses as well as the acquisition of volume data sets at high image refresh rates ("4D-MRA"). This opened doors for many new applications in non-invasive vascular imaging, including simultaneous anatomic and functional analysis of many vascular pathologies including arterio-venous malformations. Different methods were established to acquire 4D-MRA using various strategies to acquire k-space trajectories over time in order to optimize imaging according to clinical needs. These include "keyhole"-based techniques (e. g. 4D-TRAK), TRICKS - both with and without projection - and HYPR-reconstruction, TREAT, and TWIST. Some of these techniques were first introduced in the 1980 s and 1990 s, were later enhanced and modified, and finally implemented in the products of major vendors. In the last decade, a large number of studies on the clinical applications of TR-MRA was published. This manuscript provides an overview of the development of TR-MRA methods and the 4D-MRA techniques as they are currently used in the diagnosis, treatment and follow-up of vascular diseases in various parts of the body.
authors: D R
authors: DR
authors: Hadizadeh
authors: C
authors: C
authors: Marx
authors: J
authors: J
authors: Gieseke
authors: H H
authors: HH
authors: Schild
authors: W A
authors: WA
authors: Willinek
mesh_terms: D000328:Adult; D000368:Aged; D001132:Arm / Q000098:blood supply; D003287:Contrast Media; D003937:Diagnosis, Differential; D004867:Equipment Design; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D002538:Intracranial Arteriovenous Malformations / Q000175:diagnosis; D062069:Inventions; D007866:Leg / Q000098:blood supply; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods*; D008297:Male; D058729:Peripheral Arterial Disease / Q000175:diagnosis; D013927:Thrombosis / Q000175:diagnosis; D014652:Vascular Diseases / Q000175:diagnosis*
chemical_list: D003287:Contrast Media