The dentatorubrothalamic tract (DRTT) has been suggested as the anatomical substrate for deep brain stimulation (DBS)–induced tremor alleviation. So far, little is known about how accurately and reliably tracking results correspond to the anatomical DRTT. The objective of this study was to systematically investigate and validate the results of different tractography approaches for surgical planning.
The authors retrospectively analyzed 4 methodological approaches for diffusion tensor imaging (DTI)–based fiber tracking using different regions of interest in 6 patients with essential tremor. Tracking results were analyzed and validated with reference to MRI-based anatomical landmarks, were projected onto the stereotactic atlas of Morel at 3 predetermined levels (vertical levels −3.6, −1.8, and 0 mm below the anterior commissure–posterior commissure line), and were correlated to clinical outcome.
The 4 different methodologies for tracking the DRTT led to divergent results with respect to the MRI-based anatomical landmarks and when projected onto the stereotactic atlas of Morel. There was a statistically significant difference in the lateral and anteroposterior coordinates at the 3 vertical levels (p < 0.001, 2-way ANOVA). Different fractional anisotropy values ranging from 0.1 to 0.46 were required for anatomically plausible tracking results and led to varying degrees of success. Tracking results were not correlated to postoperative tremor reduction.
Different tracking methods can yield results with good anatomical approximation. The authors recommend using 3 regions of interest including the dentate nucleus of the cerebellum, the posterior subthalamic area, and the precentral gyrus to visualize the DRTT. Tracking results must be cautiously evaluated for anatomical plausibility and accuracy in each patient.
ABBREVIATIONSAC = anterior commissure; AP = anteroposterior; DBS = deep brain stimulation; DRTT = dentatorubrothalamic tract; DTI = diffusion tensor imaging; ET = essential tremor; FA = fractional anisotropy; fct = fasciculus cerebellothalamicus, per the Morel atlas; LAT = lateral; ML = medial lemniscus; ml = medial lemniscus, per the Morel atlas; PC = posterior commissure; PSA = posterior subthalamic area; PT = pyramidal tract; RN = red nucleus; ROI = region of interest; STN = subthalamic nucleus; TRS = Fahn-Tolosa-Marin tremor rating scale; VERT = vertical; Vim = ventral intermediate nucleus; VLp = ventrolateral posterior part of the thalamus.
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