New Approaches in MRI at 3T Dedicated to Targeting Subthalamic Nucleus on Parkinsonian Patients
New Approaches in MRI at 3T Dedicated to Targeting Subthalamic Nucleus on Parkinsonian Patients
Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a validated procedure, used
 in many French and international centers for the treatment of severe forms of Parkinson's
 disease (PD). The improvement of parkinsonian motor symptoms by stimulation of the STN is 50
 to 80% on average. The main advantage of DBS is that the surgery has low morbidity and
 mortality, it is adaptable to the patient's symptoms and its effect is reversible. This
 treatment is now a routine and more than 85,000 patients worldwide have benefited from the
 installation of this system. Since 1997, this treatment is available to patients followed in
 the Pitié Salpêtrière (GHPS).

 The accuracy of preoperative anatomic targeting in stereotactic neurosurgery will improve
 with the use of high-field MRI. However, several new issues and inherent in that high-field
 MRI should be evaluated before the images can be used directly.

 The chosen sequences must be short to be feasible, minimizing patient discomfort, and
 evaluated on several patients to ensure the low interindividual variability. In addition, the
 quality of the display on all of the sections should provide a reliable three-dimensional
 information. Finally, the quality of targeting and its possible improvement should be
 checked.
Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a validated procedure, used
 in many French and international centers for the treatment of severe forms of Parkinson's
 disease (PD). The improvement of parkinsonian motor symptoms by stimulation of the STN is 50
 to 80% on average. The main advantage of DBS is that the surgery has low morbidity and
 mortality, it is adaptable to the patient's symptoms and that its effect is reversible. This
 treatment is now a routine and more than 85,000 patients worldwide have benefited from the
 installation of this system. Since 1997, this treatment is available to patients followed in
 the Pitié Salpêtrière (GHPS).

 The quality of the implantation of stimulating electrodes into deep brain structures to
 achieve, particularly in the NST for PD patients, is crucial to obtain an excellent result.
 Accurate identification of these deep nuclei and especially the NST on MRI of each patient to
 be operated is an essential step and directly affects the smooth running of the surgery and
 the final clinical outcome.

 The visualization of the NST on MRI remains difficult, variable between patients, requiring
 specific sequences or even sequences dedicated to this activity. In GHPS the investigators
 opted for the realization of an efficient particular sequence for viewing the NST but the
 latter has several disadvantages the first being its duration. Indeed, the patient needs to
 keep still, head fixed for 40 minutes, and this major constraint is sometimes impossible due
 to the importance of abnormal movements. The second is the variability between patients with
 visualization being sometimes inconspicuous. The third is the susceptibility of this sequence
 to flow artifacts at the level of the third ventricle that significantly disrupt viewing NST.

 The new MRI techniques available for some years, especially at 3 Tesla should allow better
 visualization of the deep nuclei of the brain and NST in particular. Indeed, the high-field
 MRI has become an indispensable tool for both define the morphological and structural
 features but also functional and metabolic deep nuclei of the brain, particularly the NST.

 The accuracy of preoperative anatomic targeting in stereotactic neurosurgery will improve
 with the use of high-field MRI. However, several new issues and inherent in that high-field
 MRI should be evaluated before the images can be used directly.

 The chosen sequence must be short to be feasible, minimizing patient discomfort, and
 evaluated several patients to ensure the low interindividual variability. In addition, the
 quality of the display on all of the sections should provide a reliable three-dimensional
 information. Finally, the quality of targeting and its possible improvement should be
 checked.
Inclusion Criteria:

 -  Diagnosis of idiopathic Parkinson's disease (according to the criteria of the "United
 Kingdom Parkinson's Disease Society Brain Bank";

 -  Age between 18 and 70 years

 -  motor complications in the form of fluctuations in motor state or induced dyskinesias
 dopaminergic therapy, despite optimal medical treatment;

 -  Excellent responsiveness to levodopa (improved motor UPDRS score of higher than 50%
 during the acute test with levodopa)

 -  People who voluntarily accepted and intelligently participate in the study (signing a
 written consent)

 -  Patient receiving social health insurance

 Exclusion Criteria:

 -  Patients carry an apomorphine pump used in single and continuous treatment;

 -  scalable psychiatric pathology;

 -  Dementia (MMS <24/30);

 -  Existence of against-indications to MRI (cardiac or neural stimulator, ferromagnetic
 surgical clips, implants and metal objects, intraocular foreign bodies, pregnancy,
 claustrophobia).

 -  Persons under guardianship, trusteeship or any other administrative or judicial
 deprivation of rights and freedom