Spiral imaging on a small-bore system at 4.7T.
Spiral imaging has a number of advantages for ultrafast data acquisition. However, implementation on high-field small-bore systems requires carefully addressing the issues of inhomogeneity-induced blurring and gradient hardware constraints. In this paper, spiral imaging on a 40-cm-bore 4.7T CSI Omega System (Bruker Instruments) is discussed. A constant-voltage gradient waveform design algorithm is developed to reduce readout times as well as minimize waveform distortions due to gradient amplifier nonlinearities. Residual errors are then measured and taken into account in the image reconstruction procedure. Multiple spiral interleaves as well as a multifrequency reconstruction algorithm are used to decrease blurring of off-resonance spins. Both phantom and in vivo images demonstrate the performance of the resulting pulse sequences.
Department of Radiology, Stanford University, California 94305-5488, USA.
D M
DM
Spielman
J M
JM
Pauly
D000273:Adipose Tissue / Q000033:anatomy & histology; D000465:Algorithms; D000818:Animals; D016477:Artifacts; D003287:Contrast Media; D004867:Equipment Design; D005682:Gadolinium; D019786:Gadolinium DTPA; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008055:Lipids; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008961:Models, Structural; D009942:Organometallic Compounds; D009991:Oscillometry; D004369:Pentetic Acid / Q000031:analogs & derivatives; D051381:Rats; D012815:Signal Processing, Computer-Assisted; D014867:Water
D003287:Contrast Media; D008055:Lipids; D009942:Organometallic Compounds; D014867:Water; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA