Navigator accuracy requirements for prospective motion correction.
Prospective motion correction in MRI is becoming increasingly popular to prevent the image artifacts that result from subject motion. Navigator information is used to update the position of the imaging volume before every spin excitation so that lines of acquired k-space data are consistent. Errors in the navigator information, however, result in residual errors in each k-space line. This paper presents an analysis linking noise in the tracking system to the power of the resulting image artifacts. An expression is formulated for the required navigator accuracy based on the properties of the imaged object and the desired resolution. Analytical results are compared with computer simulations and experimental data.
Maclaren
Julian
J
Medical Physics, Department of Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany. julian.maclaren@uniklinik-freiburg.de
Speck
Oliver
O
Stucht
Daniel
D
Schulze
Peter
P
Hennig
Jürgen
J
Zaitsev
Maxim
M
D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009038:Motion; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity