MR-Guided Focused Ultrasound in the Treatment of Subcortical Lesional Epilepsy

The purpose of this study is to evaluate the feasibility, safety, and initial effectiveness
of ExAblate thermal ablation of a subcortical focal epileptic target area in the brain of
patients suffering from medication-refractory epilepsy, using the ExAblate transcranial
system to produce multiple sonications targeted in the lesion of interest. The Investigators
will establish the feasibility and collect data to establish the basic safety of this type of
treatment as the basis for later studies that will evaluate its full clinical efficacy.

The hypotheses tested are that:

1. MRgFUS treatment of subcortical lesional epilepsy is feasible and safe, with a low risk
of adverse effects as evaluated during the follow-up period.

2. ExAblate treatment of subcortical lesions in patients with subcortical lesional epilepsy
reduces the seizure frequency.

Inclusion Criteria:

- Seizure refractory to at least three standard antiepileptic medications at adequate
doses, failed for lack of efficacy. This may include a rescue medication designated
use as PRN.

- A minimum of 3 seizures per month for 2 months by patient diary started at intake
interview.

- Subjects should have partial-onset seizures with or without secondary generalization.

- Subjects should have evidence suggesting the target lesion is the source of seizures
by standard clinical criteria including at least the description of seizures, physical
examination, neuroimaging, and video EEG monitoring capturing at least one seizure.

- Subjects must be taking 2 medications during the Baseline period and the dosage must
be stable.

- A diagnosis of intractable epilepsy secondary to a dysplastic subcortical lesion which
would include: Hypothalamic hamartoma, Periventricular nodular hetereotopia,
Dysembryoplastic neuroepithelial tumor (DNET), Cortical dysplasia, or Tuberous
sclerosis

Exclusion Criteria:

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

- 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.).

- Patients with malignant brain tumors.

- Patients with a known history of psychogenic non-epileptic spells in the last three
years.

- Patients with a vagal nerve stimulator, deep brain stimulator, other implanted
electronic device, or prior radiofrequency lesion techniques.

- Lesions in the brainstem or cerebellum.

- Subjects with symptomatic generalized epilepsy.

- Subjects with only simple partial seizures.

- Subjects who have had convulsive status epilepticus within 12 months prior to
baseline.

- Subjects with a prior diagnosis of psychogenic/non-epileptic seizures within the last
5 years.

- Subjects who are candidates for traditional open surgery or elect to receive
traditional open surgery are excluded.