Automatic field map generation and off-resonance correction for projection reconstruction imaging.
A new projection reconstruction technique utilizes the oversampling of low spatial frequencies to estimate and correct for off-resonance effects. Interleaved spokes are acquired at one of two different echo times. From separated early-TE and late-TE raw data, two one-quarter resolution images are reconstructed and a one-quarter resolution field map is computed. Multifrequency reconstruction with all the data is then used to simultaneously correct for off-resonance and compensate for the difference in echo times. Resulting images obtained on phantoms and in vivo demonstrate significantly reduced off-resonance artifact without the acquisition of a separate field map.
Nayak
K S
KS
Department of Electrical Engineering, Stanford University, California 94305-9510, USA. nayak@lad.stanford.edu
Nishimura
D G
DG
D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008954:Models, Biological; D019047:Phantoms, Imaging; D011152:Popliteal Vein / Q000033:anatomy & histology; D012680:Sensitivity and Specificity; D013997:Time Factors