title: Time-resolved MR angiography of the legs at 3 T using a low dose of gadolinium: initial experience and contrast dynamics.
abstract: OBJECTIVE
  This article describes our initial clinical experience with time-resolved MR angiography (MRA) of the legs using the time-resolved imaging with stochastic trajectories (TWIST) technique with a half dose of gadolinium.
  
  
  METHODS
  Thirty-four patients underwent a TWIST examination of the legs at 3 T. Thirty-three patients also underwent a bolus-chase MRA examination in the same setting. Times elapsed between the start of contrast injection and the appearance of contrast material (t(A)) and peak enhancement of the arteries in the legs (t(B)) were analyzed. The number of patients with examinations affected by venous contamination was determined. The differences in t(A) and t(B) between cases in which venous contamination was present or absent were evaluated using a two-tailed Student t test.
  
  
  RESULTS
  The TWIST technique using a half dose of gadolinium provided diagnostic-quality images of all patients. The mean t(A) was 35.5 ± 8.8 (SD) seconds (range, 17.8-60.4 seconds), and the mean t(B) was 59.1 ± 15.1 seconds (range, 31-98.8 seconds). Venous contamination was observed in bolus-chase MRA images of 52.9% of patients. The relationship between venous contamination and t(A) was not statistically significant (p = 0.13). The incidence of venous contamination was higher in patients with lower values of t(B) (p = 0.01).
  
  
  CONCLUSIONS
  The described low-dose clinical experience with TWIST and the contrast dynamics information gained from this study could aid radiologists in planning protocols for leg MRA examinations.
authors.affiliation: Department of Radiology, University Hospitals of Cleveland, Case Western Reserve University, 11100 Euclid Ave, 123 Bolwell Bldg, Cleveland, OH 44106, USA. gurpreet10ff@yahoo.co.in
authors.forename: Gurpreet Singh
authors.initials: GS
authors.lastname: Sandhu
authors.forename: Rod P
authors.initials: RP
authors.lastname: Rezaee
authors.forename: John
authors.initials: J
authors.lastname: Jesberger
authors.forename: Katherine
authors.initials: K
authors.lastname: Wright
authors.forename: Mark A
authors.initials: MA
authors.lastname: Griswold
authors.forename: Vikas
authors.initials: V
authors.lastname: Gulani
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage* / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D007866:Leg / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D008875:Middle Aged; D009942:Organometallic Compounds / Q000008:administration & dosage* / Q000493:pharmacokinetics; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine