Characterizing coronary motion and its effect on MR coronary angiography--initial experience.
OBJECTIVE
To characterize coronary artery motion as a prescan procedure to select the optimum scan setting that will produce high-resolution images.


METHODS
A 2D real-time scan was used to image the major coronary arteries during breath-holding and free-breathing conditions. With the use of the 2D images, motion displacement of each artery was measured along three axes. Motion data obtained from a computer simulation were used to estimate point-spread functions (PSFs) associated with different high-resolution spiral acquisition strategies, including real-time, cardiac-gated, and respiratory-gated acquisitions. The simulation output determined the optimum acquisition and scan parameters that would produce the highest-spatial-resolution images of the coronary arteries. The effects of heart rate (HR), extended breath-holding, and number of slices per heart cycle were also investigated.


RESULTS
Substantial variations in coronary motion occur among individuals, which directly influences the optimum parameters for a high-resolution scan. Lower HRs and longer breath-holds yield substantially increased spatial resolution. The maximum number of slices per heart cycle can also be determined to minimize slice-to-slice distortion.


CONCLUSIONS
The results suggest that to obtain high-resolution coronary images, one should perform a prescan coronary-motion characterization for each individual so that the scan parameters can be optimized before data acquisition.
Al-Kwifi
Osama
O
Imaging Research Program, Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada. osama@sten.sunnybrook.utoronto.ca
Stainsby
Jeffrey
J
Foltz
Warren D
WD
Sussman
Marshall S
MS
Huang
Yuexi
Y
Wright
Graham A
GA
D003198:Computer Simulation; D017023:Coronary Angiography / Q000379:methods*; D003331:Coronary Vessels / Q000033:anatomy & histology*; D006321:Heart / Q000502:physiology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D018810:Magnetic Resonance Angiography; D009038:Motion