title: Initial clinical evaluation of a non-contrast-enhanced MR angiography method in the distal lower extremities.
abstract: OBJECTIVE
  To report the initial experience and diagnostic performance applying a novel flow-dependent non-contrast-enhanced MR angiography (NCE-MRA) method, in patients with suspected peripheral vascular disease, in comparison with established contrast-enhanced MRA (CE-MRA).
  
  
  METHODS
  The lower legs of 34 patients were imaged at 1.5 T with both NCE-MRA and CE-MRA. The NCE-MRA method consisted of a cardiac-gated balanced-SSFP sequence with controllable flow-suppression preparation. Flow-suppressed and unsuppressed datasets were subtracted to obtain angiograms. Two experienced radiologists assessed both NCE-MRA and CE-MRA images, first independently and then in consensus to resolve significant disagreements. Signal loss, vessel conspicuity, vascular disease, venous contamination, artifacts, and diagnostic confidence were assessed.
  
  
  RESULTS
  Using the CE-MRA as the "gold standard," the per-segment sensitivity and specificity for detection of significant disease were 81.7% and 90.9%, respectively. Mean diagnostic confidence (scale 0-4) was 3.4 for NCE-MRA and 3.9 for CE-MRA. Most vessel segments were well visualized but the popliteal arteries often suffered some technique-related signal loss.
  
  
  CONCLUSIONS
  The NCE-MRA method was able to visualize most vessel segments with good or excellent confidence, few artifacts, and excellent background suppression, giving moderate agreement with CE-MRA. However, some segments were poorly visualized, probably due to flow profile distortion in these patients.
authors: Department of Radiology, Addenbrooke's Hospital, Cambridge, UK.
authors: Andrew Nicholas
authors: AN
authors: Priest
authors: Ilse
authors: I
authors: Joubert
authors: Andrew Philip
authors: AP
authors: Winterbottom
authors: Teik Choon
authors: TC
authors: See
authors: Martin John
authors: MJ
authors: Graves
authors: David John
authors: DJ
authors: Lomas
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D035002:Lower Extremity / Q000098:blood supply* / Q000473:pathology; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D016491:Peripheral Vascular Diseases / Q000473:pathology*; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media
keywords: MRA; non-contrast enhanced MR angiography; peripheral vascular disease