Susceptibility Weighted Imaging

Title: Susceptibility enhanced 3 Tesla T1-weighted SPGR of the midbrain nuclei for guidance of deep brain stimulation implantation Authors: Geoffrey S. Young, Feng Feng, Hao Shen, Nan-kuei Chen Neurosurgery (2009): In Press Abstract: Surgical planning for deep brain stimulation (DBS) implantation procedures requires T1¬weighted images for stereotactic navigation. Since the subthalamic nucleus (STN), the main target for DBS, and other midbrain nuclei cannot be visualized on the stereotactic guidance T1-weighted images (T1WI), additional T2-weighted imaging (T2WI) is generally acquired and registered to the T1WI for surgical targeting. Surgical planning based on the registration of the two datasets is subject to error resulting from inconsistent geometric distortions and any subject movement between two scans. Here we propose a new method to produce susceptibility-enhanced contrast-optimized T1-weighted 3DSPGR (SECOT1) images with enhanced contrast for midbrain nuclei within the volumetric T1WI dataset itself, eliminating the need for an additional T2WI scan. The scan parameters of 3D SPGR are chosen in a way that (1) T1¬weighted images can be obtained from conventional magnitude reconstruction, and (2) images with high contrast between midbrain nuclei and surrounding tissues can be produced from the same data by performing susceptibility weighted imaging reconstruction on a chosen region of interest. In addition, our preliminary experience suggests that the resulting contrast between the midbrain nuclei is superior to the current state-of-the-art FSE T2WI in depiction of the STN as distinct from the substantia nigra pars reticulata (SNr) and clear depiction of the nucleus ventrointermedius externus (Vim) of thalamus.