Saikat Sengupta1, Brian E. Welch1,2, Yansong Zhao2, David Foxall2, Piotr Starewicz3, Adam Anderson1, Malcolm Avison1, John Gore1
1VUIIS, Vanderbilt University, Nashville, TN, USA; 2Philips Medical Systems, Cleveland, OH, USA; 3Resonance Research, Inc., Billerica, MA, USA
Dynamic Shimming (DS) is a technique for obtaining optimal Bo field homogeneity over a volume by updating the shim coil currents for every slice (or in general, location) in a multislice acquisition in real time. DS can produce better field homogeneity within each slice than global volume shimming methods and hence lower susceptibility artifacts. We have implemented DS on a human 7T system. Considerable improvements in Bo homogeneity and image distortions compared to global shimming have been shown. The use of actively shielded Z2 shim coil is also shown to be necessary for maintaining image quality with dynamic shimming.