title: Time-resolved lower extremity MRA with temporal interpolation and stochastic spiral trajectories: preliminary clinical experience.
abstract: OBJECTIVE
  To assess added value of a new time-resolved technique with temporal interpolation and stochastic spiral trajectory through k-space and parallel imaging (TR-MRA) to conventional bolus chase MRA (BC-MRA) for infragenual peripheral artery evaluation.
  
  
  METHODS
  An institutional review board-approved retrospective review of peripheral arterial disease patients was performed. Infragenual TR-MRA and BC-MRA were performed in 26 patients over four months. Two readers individually assessed image quality, diagnostic confidence, and stenosis severity and length in 13 defined below knee segments, first with BC-MRA alone, and then with a combined BC-MRA and TR-MRA reading (BC+TR-MRA). Perceived contribution of TR-MRA was rated by each reader. The reference standard was a consensus reading of both sequences. Catheter angiographic (CA) correlation was available in 6 patients.
  
  
  RESULTS
  A total of 646 infragenual segments in 51 extremities were evaluated. Image quality and diagnostic confidence were superior for BC+TR-MRA compared with BC-MRA alone (P < 0.001). Adding TR-MRA improved sensitivity (85.7% versus 80.7%; P < 0.05) and diagnostic accuracy (88.1% versus 85.4%; P < 0.05) for hemodynamically significant stenosis. Venous contamination (0% versus 13.1% segments) and motion (0.9% versus 8.0%) were decreased for BC+TR-MRA versus BC-MRA alone, P < 0.01. For BC+TR-MRA, TR-MRA was rated more useful than BC-MRA in 30/51 legs (58.8%). TR-MRA identified retrograde flow in 5 segments. Where available, there was high concordance between CA and BC+TR-MRA (91.6%) for stenosis.
  
  
  CONCLUSIONS
  Adding TR-MRA with temporal interpolation and stochastic spiral trajectories to bolus chase MRA improves image quality, diagnostic confidence and accuracy. It provides hemodynamic information and minimizes venous contamination and patient motion.
authors.affiliation: Department of Radiology, NYU Langone Medical Center, New York, New York, USA. ruth.lim@nyumc.org
authors.forename: Ruth P
authors.initials: RP
authors.lastname: Lim
authors.forename: Jason S
authors.initials: JS
authors.lastname: Jacob
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Hecht
authors.forename: Danny C
authors.initials: DC
authors.lastname: Kim
authors.forename: Steven D
authors.initials: SD
authors.lastname: Huffman
authors.forename: Sooah
authors.initials: S
authors.lastname: Kim
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
authors.forename: Gerhard
authors.initials: G
authors.lastname: Laub
authors.forename: Mark A
authors.initials: MA
authors.lastname: Adelman
authors.forename: Vivian S
authors.initials: VS
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003627:Data Interpretation, Statistical; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D035002:Lower Extremity / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008875:Middle Aged; D016491:Peripheral Vascular Diseases / Q000175:diagnosis*; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013269:Stochastic Processes