Name of the Procedure:

Magnetoencephalography (MEG) Recording and Analysis for Evoked Magnetic Fields, Single Modality (e.g., Sensory, Motor, Language, or Visual Cortex Localization).

Summary

Magnetoencephalography, or MEG, is a non-invasive diagnostic procedure that measures the magnetic fields produced by neuronal activity in the brain. It helps to pinpoint specific functional areas, such as those involved in sensory processing, movement, language, or vision.

Purpose

MEG is used to map brain function and detect abnormalities in the brain's activity. The primary goal is to localize areas responsible for different functions and to identify changes associated with various neurological conditions. It provides critical information for treatment planning, especially for patients undergoing brain surgery.

Indications

• Epilepsy: To locate the origin of seizures.
• Brain tumors: To delineate functional areas for surgical planning.
• Neurological conditions: To assess brain activity in disorders like multiple sclerosis and autism.
• Pre-surgical evaluation: To map critical brain areas before neurosurgery.
• Stroke: To evaluate functional disturbances.

Preparation

• Patients may need to remove metal objects and electronic devices.
• No specific fasting or medication adjustments are typically required.
• A thorough medical history and any prior diagnostic tests, such as MRI or CT scans, may be reviewed.

Procedure Description

1. The patient lies on a comfortable bed under an array of sensors called MEG sensors.
2. The sensors detect magnetic fields produced by neuronal activity.
3. During the procedure, the patient may be asked to perform specific tasks or respond to stimuli, such as lights or sounds, to evoke brain activity.
4. The collected data is then analyzed to create detailed maps of brain function.

Tools and Equipment:

• MEG Scanner
• Stimulus presentation equipment (e.g., visual, auditory equipment)

Anesthesia or Sedation:

• None required as the procedure is non-invasive and painless.

Duration

The procedure typically takes between 1 to 2 hours, depending on the complexity and number of tasks being evaluated.

Setting

MEG is usually performed in specialized diagnostic centers or hospitals equipped with an MEG scanner.

Personnel

• Neurologists or Neuroscientists specializing in neurophysiology.
• Technicians trained to operate MEG equipment.
• Radiologists or Medical Physicists for data analysis.

Risks and Complications

MEG is a safe procedure with minimal risks. There are no known significant complications as it is non-invasive and does not involve exposure to radiation.

Benefits

• Accurate localization of brain functions.
• Non-invasive and comfortable for the patient.
• Provides valuable information for surgical planning, reducing the risk of postoperative deficits.

Recovery

No special recovery is needed. Patients can usually resume normal activities immediately after the procedure. Follow-up appointments may be scheduled to discuss the results.

Alternatives

• Electroencephalography (EEG): Measures electrical activity but offers less precise spatial resolution.
• Functional MRI (fMRI): Maps brain activity using blood flow changes but requires lying still for longer periods.
• Positron Emission Tomography (PET): Uses radioactive tracers to measure brain activity but involves radiation exposure.

Patient Experience

Patients will lie still on a comfortable bed for the duration of the scan. They may be asked to perform simple tasks or respond to stimuli. The process is generally painless and non-intrusive. Comfort measures are taken to ensure the patient remains relaxed, and breaks can be provided if necessary.