Short TE (15ms) Spectroscopic Imaging of the Human Brain at 7T Using Transceiver Arrays and B1 Shimming Based Localization

Introduction: Despite the presence of ultra high field systems (7T) dating from late 1990s, there have been few reports of their use in spectroscopic imaging (SI) studies. This limitation is due to the inherent disadvantages of high field which result in a 5-12 fold increase in power deposition at 7T in comparison to 3T. These problems become especially severe when in–plane volume localization is used for SI. To overcome these limitations we have developed a short TE (15ms) SI sequence utilizing an 8 element 7T transceiver array and a B1 shimming based method for in-plane localization. This method reduces the required peak power by 456% and does not require gradient selection, thereby eliminating spatial mis-registration errors. We have utilized this method to acquire high resolution (0.36cc) spectroscopic images of the human brain at 7T of glutamate, glutamine and macromolecules in controls with an average power deposition of 1W/kg.