Advanced

AJNR - American Journal of Neuroradiology

Published ahead of print on June 9, 2009
doi: 10.3174/ajnr.A1669

This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: ajnr.A1669v1 30/9/1717    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Google Scholar Articles by Vertinsky, A.T. Articles by Rauscher, A. PubMed PubMed Citation Articles by Vertinsky, A.T. Articles by Rauscher, A.

American Journal of Neuroradiology 30:1717-1724, October 2009
© 2009 American Society of Neuroradiology

BRAIN

Localization of the Subthalamic Nucleus: Optimization with Susceptibility-Weighted Phase MR Imaging

A.T. Vertinsky^a, V.A. Coenen^b,e, D.J. Lang^a, S. Kolind^c, C.R. Honey^b, D. Li^a and A. Rauscher^d

^aFrom the Department of Radiology (A.T.V., D.J.L., D.L.)
^bSurgical Center for Movement Disorders (V.A.C., C.R.H.), Division of Neurosurgery
^cDepartment of Physics and Astronomy (S.K.)
^dUBC MRI Research Centre (A.R.), University of British Columbia, Vancouver, British Columbia, Canada
^eDepartment of Neurosurgery (V.A.C.), Bonn University, Bonn, Germany.

Please address correspondence to: Alexander Rauscher, PhD, MRI Research Center, University of British Columbia, M10-Purdy Pavilion, 2221 Wesbrook Mall, Vancouver, BC, Canada V5T 2B5; e-mail address: rauscher{at}physics.ubc.ca

BACKGROUND AND PURPOSE: On clinical MR images, the subthalamic nuclei (STN) are poorly delineated from adjacent structures, impeding safe direct targeting for placement of electrodes in the treatment of Parkinson disease. Susceptibility-weighted MR phase imaging offers improved contrast and spatial resolution at reduced imaging times relative to clinically used T2-weighted spin-echo imaging for STN visualization. Our purpose was to assess STN visibility by using phase imaging, comparing phase and magnitude images obtained concurrently by using susceptibility-weighted imaging (SWI). The goal was to identify an efficient scanning protocol for high-quality phase images of STN.

MATERIALS AND METHODS: Seventy-eight SWI scans were acquired at 3T by using different TEs and acceleration factors. STN visibility and delimitation from adjacent structures were scored from 0 (not interpretable) to 5 (excellent). Regression analyses assessed the relationship of STN visibility to scanning parameters

RESULTS: STN were identified at all studied TEs on phase images. Visibility and delimitation of STN were consistently superior on phase images compared with magnitude images. Good visualization (score of 4) of STN on phase imaging occurred at a mean TE of 20.0 ms and a sensitivity encoding (SENSE) of 1.40. Scores of STN visualization on phase images were dependent on SENSE (P < .002) and TE (P < .031). Good delimitation of the STN on phase imaging occurred at a mean TE of 21.6 ms and a SENSE of 1.36.

CONCLUSIONS: Visualization and delimitation of STN was superior on phase images and was achieved at 3T in <2.5 minutes. A TE of 20 ms and an acceleration factor of 1.5 are recommended to visualize STN by using this method.