Spiral coronary angiography using a blood pool agent.
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.
Ringgaard
Steffen
S
MR Center, Institute of Clinical Medicine, Skejby Sygehus, Aarhus University Hospital, Brendstrupgaardsvej 100, DK-8200 Aarhus N., Denmark. steffen@mr.au.dk
Pedersen
Michael
M
Rickers
Jonas
J
Johansson
Lars O
LO
Börnert
Peter
P
Pedersen
Erik M
EM
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
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; C097921:ferumoxtran-10; D007501:Iron; D052203:Ferrosoferric Oxide