A high resolution and high contrast MRI for differentiation of subcortical structures for DBS targeting: the Fast Gray Matter Acquisition T1 Inversion Recovery (FGATIR)

Abstract

DBS depends on precise placement of the stimulating electrode into an appropriate target region. Image-based (direct) targeting has been limited by the ability of current technology to visualize DBS targets. We have recently developed and employed a Fast Gray Matter Acquisition T1 Inversion Recovery (FGATIR) 3T MRI sequence to more reliably visualize these structures. The FGATIR provides significantly better high resolution thin (1 mm) slice visualization of DBS targets than does either standard 3T T1 or T2-weighted imaging. The T1 subcortical image revealed relatively poor contrast among the targets for DBS, though the sequence did allow localization of striatum and thalamus. T2 FLAIR scans demonstrated better contrast between the STN, SNr, red nucleus (RN), and pallidum (GPe/GPi). The FGATIR scans allowed for localization of the thalamus, striatum, GPe/GPi, RN, and SNr and displayed sharper delineation of these structures. The FGATIR also revealed features not visible on other scan types: the internal lamina of the GPi, fiber bundles from the internal capsule piercing the striatum, and the boundaries of the STN. We hope that use of the FGATIR to aid initial targeting will translate in future studies to faster and more accurate procedures with consequent improvements in clinical outcomes.