Improved Visibility of the Subthalamic Nucleus on High-Resolution Stereotactic MR Imaging by Added Susceptibility (T2*) Contrast Using Multiple Gradient Echoes

E Elolf,P Dechent,G Helms,M Knauth,T Gringel,V Bockermann

doi:10.3174/ajnr.a0527

Abstract

Reliable identification of the subthalamic nucleus (STN) is a critical step in deep brain stimulation for Parkinson disease but difficult on T1-weighted stereotactic MR imaging. By simultaneous imaging of multiple gradient echoes, susceptibility contrast is added to conventional T1-weighted high-resolution MR image. Thus, the visibility of the STN is enhanced on a second co-localized dataset by exploiting the sensitivity of the T2*-relaxation to local iron deposits. The feasibility is underpinned by quantitative measurements on healthy adults.

Highlights

An established neurosurgical therapy for Parkinson disease is to place electrodes for deep brain stimulation within the subthalamic nucleus (STN).[1] Reliable identification of the anatomic borders of the STN is a critical step in stereotactic procedures.[2,3] T2-weighted MR imaging showing the iron-rich structures as hypointensities has been suggested as additional information to the poor contrast of the STN on T1-weighted highresolution 3D MR imaging.[4,5] Exploiting the increased sensitivity of T2* to local iron deposits, a multigradient echo fast low-angle shot (FLASH) technique[6] is proposed to visualize the STN
T2-weighted MR imaging showing the iron-rich structures as hypointensities has been suggested as additional information to the poor contrast of the subthalamic nucleus (STN) on T1-weighted highresolution 3D MR imaging.[4,5]
The spatial assignment was confirmed by comparison with the coregistered T2-weighted turbo spinecho images (TSE) images with the use of a stereotactic system

Summary

Introduction

An established neurosurgical therapy for Parkinson disease is to place electrodes for deep brain stimulation within the subthalamic nucleus (STN).[1] Reliable identification of the anatomic borders of the STN is a critical step in stereotactic procedures.[2,3] T2-weighted MR imaging showing the iron-rich structures as hypointensities has been suggested as additional information to the poor contrast of the STN on T1-weighted highresolution 3D MR imaging.[4,5] Exploiting the increased sensitivity of T2* to local iron deposits, a multigradient echo fast low-angle shot (FLASH) technique[6] is proposed to visualize the STN. This 3D MR technique enables simultaneous acquisition of T1weighted images for stereotactic use and images with superimposed T2* contrast to localize the STN.

Results

Conclusion