PT  - JOURNAL ARTICLE
AU  - A.T. Vertinsky
AU  - V.A. Coenen
AU  - D.J. Lang
AU  - S. Kolind
AU  - C.R. Honey
AU  - D. Li
AU  - A. Rauscher
TI  - Localization of the Subthalamic Nucleus: Optimization with Susceptibility-Weighted Phase MR Imaging
AID  - 10.3174/ajnr.A1669
DP  - 2009 Oct 01
TA  - American Journal of Neuroradiology
PG  - 1717--1724
VI  - 30
IP  - 9
4099  - http://www.ajnr.org/content/30/9/1717.short
4100  - http://www.ajnr.org/content/30/9/1717.full
SO  - Am. J. Neuroradiol.2009 Oct 01; 30
AB  - 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,.