SPIRAL SCANNING WITH ANISOTROPIC FIELD-OF-VIEW

Spiral scanning has been used to achieve much shorter scan times than conventional techniques for a wide range of applications, The major dr awback with spiral scans is blurring from off-resonant spins, which is proportional to the readout time. Blurring limits maximal spatial res olution and minimal scan time potentially achievable with spiral scann ing. Anisotropic field of view is used in conventional scanning to imp rove image quality by matching k-space trajectory to object characteri stics, Anisotropic field of view improves spatial resolution in spiral scanning without increasing scan time or blurring. The resolution imp rovement results from increased maximal k-space radius allowed by the lower field of view. A field of view reduction by a factor of 2 in one direction provides up to 60% resolution improvement in that direction . Reduced SNR also results from non-uniform k-space sampling.