title: Unenhanced calf MR angiography at 3.0 T using electrocardiography-gated partial-fourier fast spin echo imaging with variable flip angle.
abstract: OBJECTIVE
  This study was to evaluate diagnostic performance of unenhanced electrocardiography-gated fast spin echo based MRA with variable flip angle on 3.0 T for assessment of calf arteries in patients with peripheral arterial occlusive disease (PAOD).
  
  
  METHODS
  64 patients underwent unenhanced MRA (UE), time-resolved contrast-enhanced MRA of the calf and bolus-chase contrast-enhanced lower peripheral MRA (BCE). Diagnostic performance of UE was evaluated and compared with contrast-enhanced MRA in 61 patients and x-ray angiography in 10 patients.
  
  
  RESULTS
  With UE, 852 of 960 segments (88.75%) were diagnostic even in patients with arrhythmia, demonstrating similar image quality with those on BCE (P > 0.05). For those diagnostic segments, statistics revealed good agreement between unenhanced and contrast-enhanced techniques with a Kappa value of 0.77 and 0.75 for stenosis detection and visualized vessel length, respectively. When using X-ray angiography as reference standard, no significant difference was found between UE and contrast-enhanced MRA concerning sensitivity and specificity in depiction of severe stenosis and occlusion (P > 0.05).
  
  
  CONCLUSIONS
  Although further technical refinements are required, this optimized UE technique may be used as a supplement to contrast-enhanced MRA particularly in patients with PAOD in whom venous contamination occurs frequently.
authors.affiliation: Department of Radiology, Shanghai Zhongshan Hospital, Fudan University, Shanghai, 200032, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.forename: Jiang
authors.initials: J
authors.lastname: Lin
authors.forename: Fuhua
authors.initials: F
authors.lastname: Yan
authors.forename: Qingyuan
authors.initials: Q
authors.lastname: Wu
authors.forename: Weiwei
authors.initials: W
authors.lastname: Lv
authors.forename: Yan
authors.initials: Y
authors.lastname: San
authors.forename: Hong
authors.initials: H
authors.lastname: Yun
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007866:Leg / Q000098:blood supply / Q000473:pathology; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels; D055815:Young Adult
chemical_list: D013113:Spin Labels