title: Contrast enhanced MR angiography in the assessment of relevant stenoses in occlusive disease of the pelvic and lower limb arteries: diagnostic value of a two-step examination protocol in comparison to conventional DSA.
abstract: OBJECTIVE
  Contrast-enhanced MRA (ce-MRA) has been claimed by many authors as a replacement of conventional angiography evaluating peripheral arterial occlusive disease. However, reliable detection of relevant stenoses (>70%) has to be provided for planning vascular interventions. Only few data in the literature focuses on this crucial problem. The purpose of this study was to evaluate this topic using a two-step body-coil-based MRA protocol.
  
  
  METHODS
  Forty three patients presenting with 82 stenoses >/=50% and 61 stenoses >70% on conventional catheter angiogram received fast Gadolinium-DTPA-enhanced high resolution 3D MR angiography at 1.5 T covering the pelvic and peripheral vascular tree in two examination steps using the body-coil. The data were evaluated double-blinded by three readers distinguishing moderate (50-70%) from severe stenoses (>70%).
  
  
  RESULTS
  Overall sensitivity/specificity/accuracy was 84/60/70% evaluating 143 segments. Specificity was rather poor in the iliac (58%) and crural (50%) region and moderate in the femoral and popliteal level (73%). The negative predictive value ranged between 78 and 91%. The grade of stenosis tend to be overestimated rather than underestimated in all levels with positive predictive values between 55 and 78%.
  
  
  CONCLUSIONS
  Body-coil-based contrast-enhanced MRA has limited potential in distinguishing moderate from severe stenoses in peripheral occlusive disease. Overestimations are more common than underestimations. Both occur mainly in small-sized crural arteries but also in larger iliac arteries where vessel course in partition direction may cause inadequacy between voxel size and lumen diameter in severe stenosis.
authors.affiliation: Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Str. 55, D-79106 Freiburg, Germany. winterja@ruf.uni-freiburg.de
authors.forename: Jan Thorsten
authors.initials: JT
authors.lastname: Winterer
authors.forename: Oliver
authors.initials: O
authors.lastname: Schaefer
authors.forename: Peter
authors.initials: P
authors.lastname: Uhrmeister
authors.forename: Gesine
authors.initials: G
authors.lastname: Zimmermann-Paul
authors.forename: Stefan
authors.initials: S
authors.lastname: Lehnhardt
authors.forename: C
authors.initials: C
authors.lastname: Altehoefer
authors.forename: J
authors.initials: J
authors.lastname: Laubenberger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D001157:Arterial Occlusive Diseases / Q000175:diagnosis*; D003287:Contrast Media; D005260:Female; D005263:Femoral Artery / Q000473:pathology*; D006801:Humans; D007083:Iliac Artery / Q000473:pathology*; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011150:Popliteal Artery / Q000473:pathology*; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media