A High-resolution Fast Spin-echo Inversion-recovery Sequence for Preoperative Localization of the Internal Globus Pallidus
Caroline A. Reicha,
Patricia A. Hudgins
,a,
Scott K. Shepparda,
Philip A. Starra and
Roy A.E. Bakaya
a From the Greystone Imaging Center, University of Birmingham, Alabama; the Departments of Radiology (P.A.H.) and Neurosurgery (R.A.E.B.), Emory University School of Medicine, Atlanta; Philips Medical Systems (S.K.S.); and the Department of Neurosurgery (P.A.S.), University of California, San Francisco.
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FIG 1. Axial FSE-IR image [3000/40/4 (TR/TE/excitations), with TI = 200 ms, echo train length = 5, 2 mm slice thickness] through the basal ganglia. Conventional localization of the GPi is a point 22 mm lateral to the midportion of the AC-PC line. This approach does not take into account the normal variations in laterality of the GPi.
FIG 2. Anatomy of the GP. Axial diagrammatic depiction of the GPi from the GPe. The "lamina medullaris medialis" is synonymous with the GPi-GPe lamina (Borrowed with permission from Cohn and colleagues. Pre- and postoperative MR evaluation of stereotactic pallidotomy. AJNR 1998;19:1075–1080.).
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FIG 3. Axial (A) and coronal (B) fast spin-echo inversion-recovery sequences [3000/40/2–4, TI = 200 ms, echo train length = 5, 2-mm slice thickness] show GPi-GPe lamina (small arrows), separating the GPi from the GPe. On the axial image, the posterior commissure is not seen. The frame placement technique described only approximates the AC-PC line
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