Peri- and postoperative magnetic resonance imaging localization of pallidotomy

Postoperative magnetic resonance imaging (MRI) of basal ganglia functional lesions illustrates the accuracy of preoperative target localization. The technique of perioperative MRI and CT localization for pallidotomy will be discussed and correlated with the center of the lesion on postoperative standard MRI as well as three-dimensional (3-D) volume acquisition of image. Using a 1.5-tesla Signa system, a conventional acquisition of 128-slice, 256 x 256 matrix spoiled grass (SPGR) images were used for 3-D reformation. This allowed approximately 1 x 1 x 2 mm resolution over a 24-cm field of view in a T-1-weighted image. The display affords a volumetric analysis of the anatomic location and relation of the post-ventral pallidotomy to adjacent structures. Accuracy lesion placement based on perioperative MR coordinates and revealed on postoperative images is confirmed. The volume of the lesion as well as its location are factors that affect clinical outcome.