title: 3D nongadolinium-enhanced ECG-gated MRA of the distal lower extremities: preliminary clinical experience.
abstract: OBJECTIVE
  To report our initial experience implementing a noncontrast-enhanced electrocardiograph (ECG) gated fast spin echo magnetic resonance angiography (MRA) technique for assessment of the calf arteries.
  
  
  METHODS
  Noncontrast MRA images of 36 clinical patients examined over a 6-month period were evaluated by two radiologists for length and degree of stenosis of arterial segments. Diagnostic confidence in the technique was also recorded. The reference standard was a consensus reading by both radiologists using the noncontrast technique combined with two gadolinium-enhanced techniques: bolus-chase and time-resolved imaging.
  
  
  RESULTS
  For stenosis evaluation the noncontrast technique demonstrated accuracy 79.4% (1083/1364), sensitivity 85.4% (437/512), and specificity 75.8% (646/852). The sequence demonstrated high negative predictive value (92.3%, 646/700). The technique had serious artifacts leading to poor diagnostic confidence in 17 patients (47.2%). These included motion (n = 7) and artifacts specific to the sequence, including inaccurate trigger delays (n = 5), linear artifact (n = 7), and vessel blurring (n = 5). When only patients in whom there was satisfactory diagnostic confidence were considered, accuracy, sensitivity, and negative predictive value were 92.2% (661/717), 92.4% (158/171), and 97.5% (503/516), respectively.
  
  
  CONCLUSIONS
  Our results indicate that when technically successful, noncontrast-enhanced MRA using ECG-gated fast spin echo can provide accurate imaging of the calf and pedal arteries. However, further development and optimization are needed to improve the robustness of the technique.
authors.affiliation: Department of Radiology (MRI), New York University Medical Center, 560 First Avenue, New York, NY 10016, USA. limr02@med.nyu.edu
authors.forename: Ruth P
authors.initials: RP
authors.lastname: Lim
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Hecht
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
authors.forename: Niels
authors.initials: N
authors.lastname: Oesingmann
authors.forename: Samson
authors.initials: S
authors.lastname: Wong
authors.forename: Bart E
authors.initials: BE
authors.lastname: Muhs
authors.forename: Paul
authors.initials: P
authors.lastname: Gagne
authors.forename: Vivian S
authors.initials: VS
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D003251:Constriction, Pathologic / Q000175:diagnosis; D004562:Electrocardiography; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007866:Leg / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009038:Motion; D016491:Peripheral Vascular Diseases / Q000175:diagnosis; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity