Reduction of slab boundary artifact with multiple overlapping thin slab acquisition in MR angiography of the cervical carotid artery.
Multiple overlapping thin slab acquisition (MOTSA) is a magnetic resonance (MR) angiography technique combining advantages of two- and three-dimensional time-of-flight techniques. The authors studied three image acquisition parameters (flip angle, TR, and the slab excitation fraction [SEF]) and a postprocessing algorithm, to evaluate their effect on MOTSA image quality, including contrast-to-noise ratio (C/N) and the severity of the slab boundary artifact. By increasing SEF from 0.75 to 1.10, the slab boundary artifact was reduced by 29%-56% (P < .0001). The boundary artifact can be reduced an additional 46% by postprocessing of the overlapping section data. In the healthy volunteers studied, C/N of the cervical carotid artery could be increased sixfold (P < .0001) by increasing the flip angle from 10 degrees to 50 degrees, without significant worsening of the boundary artifact due to top-of-slab saturation. The effect of TR on image quality was not statistically significant for the range studied (52-70 msec). We conclude that the slab boundary artifact seen with the MOTSA MR angiography technique can be reduced significantly by optimizing imaging acquisition parameters and using a postprocessing algorithm to combine overlapping section information.
Robison
R O
RO
Department of Radiology, LDS Hospital, University of Utah 84143.
Blatter
D D
DD
Parker
D L
DL
Barney
W W
WW
Perry
D M
DM
Goodrich
K C
KC
D000328:Adult; D000465:Algorithms; D016477:Artifacts; D002339:Carotid Arteries / Q000033:anatomy & histology*; D002343:Carotid Artery, Internal / Q000033:anatomy & histology; D005583:Fourier Analysis; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D009333:Neck / Q000098:blood supply; D012815:Signal Processing, Computer-Assisted