title: Effect of bolus length of intraarterial injections on contrast-enhanced MR-angiography in patients.
abstract: OBJECTIVE
  To perform MR-guided interventions, repetitive injections of contrast agent in the arterial system are necessary. By reducing the intraarterial bolus length during image acquisition and consecutively reducing the gadolinium-chelate-based contrast agent dose, we focus on a comparable vascular depiction. The tradeoff in reducing bolus length is vascular depiction.
  
  
  METHODS
  Intraarterial gadolinium-chelate injection was performed to depict the femoropopliteal artery and infrapopliteal arteries in six patients. Six measurements with a bolus length of 20% to 100% of the total acquisition time were performed (three-dimensional [3D] Turbo-fast low-angle shot (FLASH) sequence, 1.5 T). Contrast-to-noise ratio (CNR) was determined and a consensus reading of vascular depiction was performed.
  
  
  RESULTS
  CNR values comparable 100% of bolus length were obtained for the femoropopliteal artery at >or=40% and for the infrapopliteal arteries at >or=60%. Qualitative analysis demonstrated that a bolus length of >or=60% is necessary to reveal a good diagnostic vascular depiction.
  
  
  CONCLUSIONS
  Quantitatively, a reduction of intraarterial gadolinium-chelate dosage in patients is possible down to 40% in the femoropopliteal artery and to 60% in the infrapopliteal arteries to acquire a CNR comparable to 100% of bolus length. Qualitatively, however, the bolus length can only be reduced down to 60% for both level to produce a good diagnostic vascular depiction and is, for diagnostic purposes, the limiting factor.
authors.affiliation: Radiology, University of Basel, Basel, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Hashagen
authors.forename: A-C
authors.initials: AC
authors.lastname: Schulte
authors.forename: G
authors.initials: G
authors.lastname: Bongartz
authors.forename: M
authors.initials: M
authors.lastname: Aschwanden
authors.forename: K A
authors.initials: KA
authors.lastname: Jaeger
authors.forename: R
authors.initials: R
authors.lastname: Huegli
authors.forename: A L
authors.initials: AL
authors.lastname: Jacob
authors.forename: Deniz
authors.initials: D
authors.lastname: Bilecen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001157:Arterial Occlusive Diseases / Q000175:diagnosis*; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D005682:Gadolinium / Q000008:administration & dosage*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007269:Injections, Intra-Arterial; D007866:Leg / Q000098:blood supply; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011150:Popliteal Artery / Q000473:pathology*
chemical_list: D003287:Contrast Media; D005682:Gadolinium