MAGNES 2500 WH BIOMAGNETOMETER

K962317 · Biomagnetic Technologies, Inc. · OLY · May 7, 1997 · Neurology

Device Facts

• Record ID: K962317
• Device Name: MAGNES 2500 WH BIOMAGNETOMETER
• Applicant: Biomagnetic Technologies, Inc.
• Product Code: OLY · Neurology
• Decision Date: May 7, 1997
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 882.1400
• Device Class: Class 2

Intended Use

The Magnes 2500 WH is intended for use in diagnostic procedures that require the measurement and display of extracranial magnetic fields and information about the electrical activity in the brain as inferred from those fields.

Device Story

Magnes 2500 WH biomagnetometer detects/measures extracranial magnetic fields produced by human brain. System uses array of 148 superconducting magnetic field pickup coils (magnetometers) and SQUIDs cooled by liquid helium via solid thermal conduction. Ancillary equipment includes magnetically shielded room, non-magnetic patient gantry/table, sensory stimulus systems (somatosensory, auditory, visual, motor), and head position measurement system. Operated by clinicians in medical facility. Computer workstation processes signals; displays results as waveforms, contour maps, or equivalent single current dipoles. Provides data for diagnosis or therapy planning; benefits patient by non-invasively mapping brain electrical activity.

Clinical Evidence

Bench testing only. Comparative studies using head phantoms evaluated dipole localization (location, strength, orientation), sensitivity under varying helium levels, and head position measurement accuracy. Results showed no significant differences between Magnes 2500 WH and Magnes II predicate.

Technological Characteristics

148-channel magnetometer array; SQUID sensors; liquid helium cooling via solid thermal conduction; magnetically shielded room (nickel-rich alloy/aluminum); non-magnetic gantry/table; sensory stimulus hardware; computer-based data acquisition/analysis; head position measurement via low-level transmitter coils.

Indications for Use

Indicated for patients whose physician requires information regarding brain-produced magnetic fields and source locations to assist in diagnosis or therapy planning.

Regulatory Classification

Identification

An electroencephalograph is a device used to measure and record the electrical activity of the patient's brain obtained by placing two or more electrodes on the head.

Predicate Devices

• Magnes II biomagnetometer (K941553)

Submission Summary (Full Text)

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K962317

MAY - 7 1997

# 510(k) Summary

This 510(k) Summary is being submitted pursuant to the requirement of 21 CF 807.92(c).

1. Submitted By: Biomagnetic Technologies, Inc.
9727 Pacific Heights Blvd
San Diego, CA 92121
Telephone: [phone]
Fax: [phone]

Contact: Eugene C Hirschkoff, Ph.D.
Director, Clinical Applications

Date prepared: April 23, 1996

2. Device trade name: Magnetic Encephalograph
Proprietary name: Magnes 2500 WH biomagnetometer

3. Substantial equivalence is claimed to the Magnes II biomagnetometer, manufactured and marketed by Biomagnetic Technologies, Inc. (Reference 510(k) K941553)

4. Description of Device: The Magnes 2500 WH biomagnetometer (hereafter "Magnes 2500 WH") comprises a magnetic sensor for detecting and measuring the magnetic fields produced by the human brain, along with the auxiliary equipment required to perform the measurements in a conventional medical facility environment and to display the results of the measurements to physicians in a variety of ways.

The sensor utilizes an array of superconducting magnetic field pickup coils arranged in such a manner as to sense the magnetic fields over the portion of the skull enclosing the brain. For each such coil, a superconducting quantum interference device (SQUID) is used to detect the current induced in that coil by the brain magnetic field and produce a voltage proportional to the magnetic flux change. Conventional electronic and computer circuitry is used to amplify, filter, digitize, store and display the result of the measurement. The sensor includes an insulated reservoir of liquid helium as a refrigerant for cooling the superconducting components - pickup coils, SQUIDs, and interconnecting leads - to temperatures below their superconducting transition temperature. Heat is conducted from these superconducting elements along thermally conductive pathways into the helium reservoir.

Provided as part of the Magnes 2500 WH biomagnetometer are the following ancillary items:

- Magnetically shielded room, comprised primarily of nickel-rich alloy and aluminum sheeting, to provide shielding from environmental sources of magnetic or rf noise
- Manually operated non-magnetic gantry to place the sensor over the head of the patient in either a seated or supine position

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Non-magnetic patient table with hydraulic elevation, to support the patient securely in either seated or supine position

Non-magnetic patient monitoring and communication devices, including video monitor, intercom, and head motion detector

Head shape and head position measurement system, to provide head shape and location relative to the sensor for data modeling and display

Computer workstation, operator console, and software to control system operation, data acquisition and storage, and data analysis and display

Sensory stimulus systems, to provide stimulation of the patient's somatosensory, auditory, visual, and motor systems for magnetic measurement of evoked response

Results of the measurement of magnetic fields produced by the brain are available in tabular form and may be visualized as waveforms, contour maps of lines of equal magnetic field values, and as equivalent single current dipoles.

5. Intended Use: The Magnes 2500 WH is intended for use in diagnostic procedures that require the measurement and display of extracranial magnetic fields and information about the electrical activity in the brain as inferred from those fields.

6. Technological Characteristics: The Magnes 2500 WH operates with the same principles of operation as the predicate device, the Magnes II biomagnetometer. Magnetic field changes induce currents in superconducting pickup coils, those currents are detected and converted to voltages by superconducting quantum interference devices or SQUIDs, and those voltages are amplified, filtered, digitized, stored, analyzed and displayed for use by a physician. The primary technological difference between the Magnes II and the Magnes 2500 WH is that the latter features 148 pickup coils distributed over the entire surface of the skull overlying cortical tissue while the former features two arrays of 37 pickup coils, each covering a circular area approximately $15\mathrm{cm}$ in diameter.

Because the cryogenic container housing the pickup coils is by necessity rigid and head sizes and shapes vary from patient to patient, the distance from some of the pickup coils to the skull of a patient may be greater than with the Magnes II. To compensate for this, the pickup coils are constructed as magnetometers rather than axial gradiometers as in the Magnes II. Magnetometer coils offer greater sensitivity to brain sources of magnetic fields than gradiometer coils but at the expense of greater sensitivity to extrinsic magnetic noise. A secondary set of pickup coils, spatially separated from the primary pickup coils, are used to detect magnetic noise and subtract it from the primary signals, creating the functional equivalent of an axial gradiometer.

The Magnes II refrigerates one set of the superconducting components of the sensor by immersing them directly in liquid helium, the other by solid thermal conduction. In the Magnes 2500 WH, all of the superconducting components are refrigerated by solid thermal conductors which thermally connect each such component to the liquid helium reservoir.

In the Magnes II, the position of the patient's head was measured using a third-party position indicator system which operated by essentially measuring the mutual inductance between small receiver coils mounted on the patient's head or in a wand and a low level rf transmitter coil mounted on one sensor housing. In the Magnes 2500 WH, the same principle of operation is

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employed, but small very low level transmitter coils are mounted on the patient's head and the field produced by those coils is measured by the biomagnetometer pickup coils themselves.

7. Non-clinical tests: The substantial equivalence between the Magnes II and Magnes 2500 WH was verified by comparative non-clinical tests of each of the technological characteristics which are different, as described in 6) above.

To demonstrate the substantial equivalence of the magnetometer pickup coils as used in the Magnes 2500 WH to the gradiometer coils as used in the Magnes II, two bench tests were run. In the first, a dipolar source in a head phantom was activated and measured with each of the sensors, both in the normal ambient environment of the factory and in the presence of artificially produced magnetic noise. The spectral content of the waveform as measured with each sensor were then compared for both conditions. The waveforms showed no significant difference from each other, in either operating condition.

As a second test of this characteristic, the dipole in the head phantom was localized using the Magnes II and Magnes 2500 WH sensors in a number of trials. There was no significant difference for any of the dipole parameters between the two sensors - physical location, strength, or orientation.

To demonstrate the substantial equivalence of the method of refrigeration, the magnetic field produced by a fixed source was detected by representative pickup coils in the Magnes 2500 WH when the helium level in the reservoir was full and when it was nearly empty. A similar test was conducted with the upper sensor of a Magnes II, in which the direct immersion method of refrigeration is used. Sensitivity of the various channels was compared for these two operating conditions and no material difference measured.

Finally, to demonstrate the substantial equivalence of the methods of measuring head position, repetitive measurements of the location of reference points on a head phantom were conducted with the positioning system in the Magnes II and with the new approach taken in the Magnes 2500 WH. No significant difference between the relative locations of the reference points was found.

8. Conclusion: The comparative non-clinical tests produced no significant differences between those elements of the Magnes II and the correspondent elements of the Magnes 2500 WH for which there has been some change in technological approach. Since all other elements of the two systems are technologically the same, we conclude that the Magnes 2500 WH is substantially equivalent to the predicate Magnes system.

Please direct any questions concerning this 510(k) Summary to the contact person noted above.

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DEPARTMENT OF HEALTH & HUMAN SERVICES
Public Health Service
Food and Drug Administration
10903 New Hampshire Avenue
Document Control Room -WO66-G609
Silver Spring, MD 20993-0002

Eugene C. Hirschkoff, Ph.D.
Director of Clinical Applications
Biomagnetic-Technologies
9727 Pacific Heights Boulevard
San Diego, California 92121-3719

Re: K962317
Trade/Device Name: Magnes 2500 WH Biomagnetometer
Regulation Number: 21 CFR 882.1400
Regulation Name: Electroencephalograph
Regulatory Class: II
Product Code: OLY
Dated (Date on orig SE ltr): March 5, 1997
Received (Date on orig SE ltr): March 6, 1997

Dear Mr. Hirschkoff:

This letter corrects our substantially equivalent letter of May 7, 1997.

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

APR - 9 2012

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Page 2 – Mr. Eugene C. Hirschkoff

Please be advised that FDA’s issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act’s requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please go to http://www.fda.gov/AboutFDA/CentersOffices/CDRH/CDRHOffices/ucm115809.htm for the Center for Devices and Radiological Health’s (CDRH’s) Office of Compliance. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH’s Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number [phone] or [phone] or at its Internet address http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely yours,


Malvina B. Eydelman, M.D.
Director
Division of Ophthalmic, Neurological, and Ear, Nose and Throat Devices
Office of Device Evaluation
Center for Devices and Radiological Health

Enclosure

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510(k) Number (if known): K962317

Place Name: Magnes 2500 WH Biomagnetometer

Indications For Use:

Use of the Magnes 2500 WH is indicated for the patient whose physician believes that information about the magnetic fields produced by that patient's brain and information about the location of the sources of those magnetic fields could contribute to diagnosis or therapy planning.

(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

(Division Sign-Of)
Division of Cardiovascular Respiratory and Neurological Devices
510(k) Number K962317

Prescription Use ☑
Per CFR 801.109

OR

Over-The-Counter Use ☐

(Optional Format 1-2-96)