Imaging Study of Tremor Disorders
Imaging Study of Tremor Disorders
To explore the pathogenesis underlying tremor in essential tremor (ET) and parkinson disease
 (PD) as well as the mechanisms of tremor suppression after Magnetic resonance-guided focused
 ultrasound (MRgFUS) thalamotomy through multi-model MRI study, and to identify imaging
 biomarkers for triaging patients for the suitability of MRgFUS thalamotomy and predicting the
 treatment effectiveness.

 Essential tremor (ET) and Parkinson disease (PD) are the most prevalent tremor disorders. ET,
 considered as a pure tremor disease, is characterized by upper limb intention or postural
 tremor, while PD is characterized by a variety of motor and nonmotor symptoms, among them
 rest tremor. A number of studies have demonstrated that Magnetic resonance-guided focused
 ultrasound (MRgFUS) thalamotomy is a minimally invasive and effective procedure suitable for
 medication-refractory tremor in patients with ET and patients with PD. However, the treatment
 effectiveness is variable among individuals. Therefore, it is important to clarify the
 pathogenesis of tremor in both ET and PD and the mechanisms of tremor arrest produced by
 MRgFUS thalamotomy to triage suitable candidates for MRgFUS thalamotomy and predict clinical
 outcomes. In addition, localization precision and individualized treatment remain to be
 improved.
Patients:

 Patients with medication-refractory ET and PD were included. Baseline materials, clinical
 rating scale for tremor (CRST) ,Unified Parkinson Disease Rating Scale (UPDRS), treatment
 parameters(energy, power, duration time, temperature, target location) , associated adverse
 effects were recorded.

 Imaging protocols:

 T2; T2 Flair; DWI; ESWAN; MRS; 3D ASL 2.0s; 3D-T1; DTI; rs-functional MRI

 Imaging evaluation:

 1. Lesion appearance and volume are measured by T2, T2 Flair, DWI, ESWAN, 3D-T1;

 2. ESWAN and MRS manifests the changes of iron deposition and metabolism，respectively;

 3. ASL shows regional cerebral blood flow associated with the procedure;

 4. DTI demonstrates the destruction of white matter integrity.

 5. Rs-functional MRI reflects alterations of resting-state brain activity.

 Treatment:

 MRgFUS thalamotomy

 Follow-up:

 Baseline (MRI+clinical evaluation); 1-day, 1-week, 1-month, 3-months, 6-months,1-year,
 2-years,3-years,4-years, 5-years (MRI+clinical evaluation)
Inclusion Criteria:

 1. Men and women age 22 years or older;

 2. A diagnosis of ET and PD as confirmed from clinical history and examination by a
 neurologist or neurosurgeon specialized in movement disorder;

 3. Intolerance to side effects of medication or poor response to medication, severe and
 disabling tremor;

 4. Regarding PD patients, the ratio of mean Unified Parkinson Disease Rating Scale
 (UPDRS) tremor scores to the mean UPDRS postural instability/gait disorder scores
 equal or greater than 1.5;

 5. Able to communicate sensations during the ExAblate TcMRgFUS treatment;

 6. All MRI examination performed according to study protocol;

 7. Having complete medical history and clinical follow up;

 8. Imaging data can be processed.

 Exclusion Criteria:

 1. Subjects with unstable cardiac status;

 2. Severe hypertension (diastolic BP > 100 on medication);

 3. Subjects with standard contraindications for MR imaging such as non-MRI compatible
 implanted metallic devices including cardiac pacemakers, size limitations, etc;

 4. Known intolerance or allergies to the MRI contrast agent (e.g. Gadolinium or
 Magnevist) including advanced kidney disease;

 5. Patient with severely impaired renal function;

 6. History of abnormal bleeding and/or coagulopathy;

 7. History of immunocompromise including those who are HIV positive;

 8. History of intracranial hemorrhage;

 9. Cerebrovascular disease (multiple CVA or CVA within 6 months);

 10. Subjects with uncontrolled symptoms and signs of increased intracranial pressure
 (e.g., headache, nausea, vomiting, lethargy, papilledema);

 11. Individuals who are not able or willing to tolerate the required prolonged stationary
 supine position during treatment (can be up to 4 hrs of total table time);

 12. Significant claustrophobia that cannot be managed with mild medication;

 13. Presence of any other neurodegenerative disease such as Parkinson-plus syndromes
 suspected on neurological examination;

 14. Presence of significant cognitive impairment;

 15. Subjects with life-threatening systemic disease;

 16. Subjects with a history of seizures within the past year;

 17. Subjects with presence or history of psychosis. -