title: Spiral coronary angiography using a blood pool agent.
abstract: OBJECTIVE
  To experimentally investigate the optimum dose of an iron-oxide-based blood pool agent for spiral coronary MR angiography (MRA), and the difference between single and multiple spiral excitations in each cardiac cycle.
  
  
  METHODS
  Images using single and triple spiral excitations in each cardiac cycle were obtained in late diastole of the left main coronary artery in eight pigs following an inversion prepulse. Measurements were obtained before and after injection of increasing doses of an iron oxide blood pool agent (Clariscan) corresponding to concentrations of 0.8, 2.2, and 3.9 mg Fe/kg BW. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured.
  
  
  RESULTS
  For 0.8 mg Fe/kg BW relative to precontrast values, a significant increase was observed for both one (SNR: 2.3, CNR: 3.8) and three (SNR: 1.4, CNR: 2.2) excitations (P < 0.01). When the dose was increased from 0.8 mg Fe/kg BW to 2.2 mg Fe/kg BW, only the SNR (P < 0.01) increased further. Significantly higher CNR (1.6-1.8) and SNR (1.4-1.6) values were seen for one excitation relative to three excitations at all concentrations (P < 0.05).
  
  
  CONCLUSIONS
  At low concentrations, an iron oxide blood pool agent can increase SNR and CNR significantly with both single excitation and triple excitations using an inversion-prepared spiral acquisition scheme. At higher concentrations, T2* effects reduce image quality.
authors: MR Center, Institute of Clinical Medicine, Skejby Sygehus, Aarhus University Hospital, Brendstrupgaardsvej 100, DK-8200 Aarhus N., Denmark. steffen@mr.au.dk
authors: Steffen
authors: S
authors: Ringgaard
authors: Michael
authors: M
authors: Pedersen
authors: Jonas
authors: J
authors: Rickers
authors: Lars O
authors: LO
authors: Johansson
authors: Peter
authors: P
authors: Börnert
authors: Erik M
authors: EM
authors: Pedersen
mesh_terms: D000818:Animals; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003911:Dextrans; D004305:Dose-Response Relationship, Drug; D005260:Female; D052203:Ferrosoferric Oxide; D007089:Image Enhancement / Q000379:methods*; D007501:Iron; D018810:Magnetic Resonance Angiography; D058185:Magnetite Nanoparticles; D008297:Male; D023421:Models, Animal; D010087:Oxides; D012680:Sensitivity and Specificity; D013552:Swine
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; C097921:ferumoxtran-10; D007501:Iron; D052203:Ferrosoferric Oxide