Case Study of Image-Guided Deep Brain Stimulation: Magnetic Resonance Imaging-Based White Matter Tractography Shows Differences in Responders and Nonresponders.
BACKGROUND
The caudal zona incerta (cZI) is an increasingly popular deep brain stimulation (DBS) target for the treatment of tremor-predominant disease. The dentatorubrothalamic tract (DRTT) is a white matter fiber bundle that traverses the cZI and can be identified using diffusion-weighted magnetic resonance imaging fiber tractography to ascertain its precise course. In this report, we compare 2 patient cases of cZI DBS, a responder and a nonresponder.


METHODS
Patient 1 (responder) is a 65-year-old man with medically refractory Parkinson disease who underwent bilateral DBS lead placement in the cZI. Postoperatively he demonstrated >90% reduction in baseline tremor and was not limited by stimulation side effects. Postoperative imaging showed correct lead placement in the cZI. Tractography revealed a DRTT within the field of stimulation, bilaterally. Patient 2 (nonresponder) is a 61-year-old man with medically refractory Parkinson disease who also underwent bilateral DBS lead placement in the cZI. He initially demonstrated >90% reduction in baseline tremor but developed disabling dystonia of his left leg and significant slurring of his speech in the months after surgery. Postoperative imaging showed bilateral lead placement in the cZI. Right-sided electrode revision was recommended and resulted in relief of tremor and reduced dystonic side effects. Tractography analysis of the original leads revealed a DRTT with an atypical anterior trajectory and a location outside the field of stimulation. Tractography analysis of the revised lead showed a DRTT within the field of stimulation.


CONCLUSIONS
Preoperative diffusion-weighted magnetic resonance imaging fiber tractography imaging of the DRTT has the potential to improve and individualize DBS planning.
Department of Radiology, Mount Sinai Hospital, New York, New York, USA; Department of Psychiatry, Mount Sinai Hospital, New York, New York, USA.
Rafael L
RL
O'Halloran
Icahn School of Medicine, Mount Sinai Hospital, New York, New York, USA.
Alexander G
AG
Chartrain
Department of Neurosurgery, Mount Sinai Hospital, New York, New York, USA.
Jonathan J
JJ
Rasouli
Department of Medicine, Division of Neurology, Mount Sinai Hospital, New York, New York, USA.
Ritesh A
RA
Ramdhani
Department of Neurosurgery, Mount Sinai Hospital, New York, New York, USA. Electronic address: brian.kopell@mountsinai.org.
Brian Harris
BH
Kopell
D000368:Aged; D001931:Brain Mapping; D002529:Cerebellar Nuclei / Q000473:pathology / Q000601:surgery*; D046690:Deep Brain Stimulation / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging / Q000379:methods*; D004567:Electrodes, Implanted; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000628:therapy*; D011183:Postoperative Complications / Q000209:etiology; D025321:Surgery, Computer-Assisted / Q000379:methods*; D017211:Treatment Failure; D016896:Treatment Outcome; D066127:White Matter / Q000473:pathology / Q000601:surgery*; D065820:Zona Incerta / Q000473:pathology / Q000601:surgery*
Caudal zona incerta; Deep brain stimulation; Dentatorubrothalamic tract; Diffusion magnetic resonance imaging fiber tractography; Tremor-predominant Parkinson disease