title: Bilateral contrast-enhanced MR angiography of the hand: diagnostic image quality of accelerated MRI using echo sharing with interleaved stochastic trajectories (TWIST).
abstract: OBJECTIVE
  To evaluate the image quality of time-resolved contrast-enhanced MRA (tr-MRA) employing echo-sharing with stochastic trajectories for the bilateral examination of the hands.
  
  
  METHODS
  In this institutional review-board approved study, Tr-MRA was compared with multiphasic contrast-enhanced MRA (mp-MRA) featuring sub-systolic venous compression in 20 healthy volunteers at 3.0 T using the following settings: TR/TE: 2.8/1.2 ms, flip angle: 25°, acceleration factor: 4, effective voxel size: 0.9 × 0.8 × 0.9 cm, acquisition time 4.9 s per 3D volume.
  
  
  RESULTS
  With tr-MRA the arterial first-pass contrast agent transit is clearly seen. On average the contrast agent arrived 34 s post-injection and reached the proper digital arteries after 44 s. The mean arterio-venous window was 13 s. Bilateral contrast enhancement was asynchronous in 56-62%. On a semiquantitative scale (0 = non-sufficient to 4 = excellent) tr-MRA (mp-MRA) yielded an average ranking of 2.8-3.6 (3.1-3.8) in the greater and intermediate sized segments and 1.3-2.0 (1.6-2.3) in the proper digital arteries.
  
  
  CONCLUSIONS
  Compared with established multiphasic ce-MRA, time-resolved MRA allows a four times faster acquisition. It reflects the natural haemodynamics of the hand arteries with no need for sub-systolic venous compression and may be beneficial in the detection of hand circulation disorders. Image quality is comparable to mp-MRA. In both techniques depiction of the proper digital arteries is limited.
authors.affiliation: Department of Radiology, University Hospital of Freiburg, Hugstetter Str 55, D-79106 Freiburg, Germany. jan.winterer@uniklinik-freiburg.de
authors.forename: Jan Thorsten
authors.initials: JT
authors.lastname: Winterer
authors.forename: P
authors.initials: P
authors.lastname: Blanke
authors.forename: A
authors.initials: A
authors.lastname: Schaefer
authors.forename: G
authors.initials: G
authors.lastname: Pache
authors.forename: M
authors.initials: M
authors.lastname: Langer
authors.forename: M
authors.initials: M
authors.lastname: Markl
mesh_terms: D000328:Adult; D003287:Contrast Media / Q000494:pharmacology; D003952:Diagnostic Imaging / Q000379:methods; D005260:Female; D006225:Hand / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007511:Ischemia / Q000473:pathology; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012984:Software; D013269:Stochastic Processes; D013997:Time Factors
chemical_list: D003287:Contrast Media