2017 Imaging for Physicists Coursebook

Summary 1

• Many reasons exists for artifacts in images – Erroneous sampling of k-space

• Aliasing • Ringing – Magnetic field errors • Gradient artifacts

• Susceptibility artifacts • Water-fat shift

• Geometrical artifacts show up in a particular direction – Phase encoding direction: aliasing – Read-out direction: susceptibility, water-fat shift

• Dephasing results in signal loss in gradient echo sequences