title: MRA of the lower extremities in patients with pulmonary embolism using a blood pool contrast agent: initial experience.
abstract: OBJECTIVE
  To evaluate the feasibility of blood pool contrast-enhanced magnetic resonance angiography (MRA) to visualize the arterial and venous vessel tree and to detect deep venous thrombosis (DVT) of the lower extremities.
  
  
  METHODS
  Nine consecutive patients with pulmonary embolism (mean age = 46 +/- 9) were randomized to various doses of NC100150 (between 0.75 and 6 mg of Fe/kg of body weight). A T1-weighted (T1W) 3D gradient recalled echo (GRE) sequence (TE = 2.0 msec, TR = 5.0 msec) was used. Two observers blinded to the dose of contrast agent assessed image quality, contrast attenuation, and appearance of thrombi.
  
  
  RESULTS
  Qualitative assessment of overall MRA image quality and semiquantitative vessel scoring revealed good to excellent delineation of venous and arterial vessel segments independent of the dose of NC100150. However, quantitative region of interest analysis revealed a significantly higher signal-to-noise ratio (SNR) in the high-dose group than in the mid- and low-dose groups of NC100150 (P < 0.01). Between dose groups, the SNR was independent of vessel type (artery or vein) and vessel segment localization (proximal or distal). All seven venous thrombi (mean length = 7.2 +/- 0.95 cm) were characterized by a very low signal intensity (SI), which was only 16.6 +/- 7% of the SI in adjacent venous segments (P < 0.0001).
  
  
  CONCLUSIONS
  High-quality MR angiograms of the lower extremities can be obtained using low concentrations of NC100150 in combination with a strong T1W 3D GRE sequence. The obvious delineation of venous thrombi suggests that this technique may be potentially used as a noninvasive "one-stop shopping" tool in the evaluation of thromboembolic disease.
authors.affiliation: Department of Radiology and Ludwig- Boltzmann-Institute for Clinical and Experimental Radiological Research, General Hospital and University of Vienna Austria. Hoffmann@helix.mgh.harvard.edu
authors.forename: Udo
authors.initials: U
authors.lastname: Hoffmann
authors.forename: Christian
authors.initials: C
authors.lastname: Loewe
authors.forename: Christoph
authors.initials: C
authors.lastname: Bernhard
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.forename: Manfred
authors.initials: M
authors.lastname: Cejna
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Herold
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schima
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D003911:Dextrans; D005240:Feasibility Studies; D005260:Female; D052203:Ferrosoferric Oxide; D006801:Humans; D007501:Iron / Q000008:administration & dosage; D007866:Leg / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D010087:Oxides / Q000008:administration & dosage; D011655:Pulmonary Embolism / Q000175:diagnosis*
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; C097921:ferumoxtran-10; D007501:Iron; D052203:Ferrosoferric Oxide