Magnetization evolution in balanced steady-state free precession with continuously moving table.
Diagnostic imaging of systemic disorders, such as peripheral vascular diseases, requires a field-of-view (FOV) larger than the local FOV available on clinical MR scanners. The continuously moving table (CMT) method acquires large FOV images in a single acquisition. Balanced steady-state free precession (bSSFP) is an attractive candidate for the CMT method due to its short repetition time and high signal-to-noise ratio. However, introducing table motion during data acquisition perturbs the magnetization evolution towards steady state. In this paper, a computer model was developed to simulate the bSSFP magnetization evolution in the presence of table motion. From these simulations, predictions were made about the maximum table velocities that would allow the magnetizations of specific tissues to evolve to the theoretical steady-state values. These predicted maximum table velocities were then successfully verified in vivo with bSSFP CMT acquisitions. For an imaging FOV <or= 35 cm, table velocities of less than 2 cm s(-1) were found to produce satisfactory CMT images.
Stafford
Randall B
RB
Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, T2N 2T9, Canada.
Sabati
Mohammad
M
Mahallati
Houman
H
Frayne
Richard
R
D016477:Artifacts; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D008280:Magnetics; D008954:Models, Biological; D009038:Motion; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D051598:Whole Body Imaging / Q000295:instrumentation* / Q000379:methods*