MAGNES II BIOMAGNETOMETER

K941553 · Biomagnetic Technologies, Inc. · OLX · May 16, 1996 · Neurology

Device Facts

• Record ID: K941553
• Device Name: MAGNES II BIOMAGNETOMETER
• Applicant: Biomagnetic Technologies, Inc.
• Product Code: OLX · Neurology
• Decision Date: May 16, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 882.1400
• Device Class: Class 2

Intended Use

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

Device Story

Magnes II Biomagnetometer detects and amplifies magnetic fields generated by brain electrical activity; utilizes superconducting signal pickup coils and SQUIDs (Superconducting Quantum Interference Devices) cooled to liquid helium temperatures. System includes two sensor units (gantry and floor mounted), electronics for analog amplification/filtering/digitization, and a master analysis processor for data storage, processing, and display. Operates within a magnetically shielded room to reduce interference. Physician/technician operates system to support patient on a table. Device transforms magnetic field inputs into visual displays of field strength, direction, and location. Provides non-contact measurement of brain activity; aids clinical diagnosis by mapping electrical sources. Second sensor unit increases simultaneous coverage area and reduces recording time compared to single-sensor systems.

Clinical Evidence

Bench testing only. Verification of physical principles performed using phantom signal sources to assess localization accuracy, signal sensitivity, and system background noise. Comparison of the second sensor against the original Magnes sensor demonstrated no significant difference in performance for the detection and display of biomagnetic signals.

Technological Characteristics

Superconducting magnetic field sensors (SQUIDs) cooled to liquid helium temperatures; two sensor units (gantry and floor mounted); magnetically shielded room; electronics for analog signal amplification, filtering, and A/D conversion; computer subsystem for data processing and display. Operates on classical electromagnetic field equations (Maxwell, Lenz). Non-contact sensing.

Indications for Use

Indicated for diagnostic procedures requiring measurement and display of extracranial magnetic fields and inferred brain electrical activity.

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 Biomagnetometer (K901215)

Submission Summary (Full Text)

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K941553
MAY 16 1996

# 510(k) SUMMARY

(a) (1) Submitted By:
Biomagnetic Technologies, Inc. (BTi)
9727 Pacific Heights Blvd.
San Diego, CA 92121

Telephone: [phone]
Fax: [phone]

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

Prepared: 15 May 1996

(2) Name of Device:
Proprietary name: Magnes® II Biomagnetometer
Device trade name: Magnetic Encephalograph

(3) Substantial Equivalence:
The Magnes II Biomagnetometer system is substantially equivalent to the Magnes Biomagnetometer system currently manufactured and marketed by Biomagnetic Technologies, Inc. (Reference 510(k) K901215)

(4) Description of Device:
The Magnes II Biomagnetometer system utilizes superconducting signal pickup coils and Superconducting Quantum Interference Devices (SQUIDs) to detect and amplify magnetic fields produced by electrical activity in the brain. The signals are amplified, filtered and digitized by signal processing electronics. The digitized signals are computer processed to produce displays of information about biomagnetic field strength, direction, and location.

The Magnes II Biomagnetometer system consists of: Two sensor units, one gantry mounted and one floor mounted, which house the superconducting components which are cooled to liquid helium temperature, an electronics subsystem for preliminary analog signal amplification, filtering, and analog-to-digital conversion, a computer subsystem "master analysis processor" to store, process, and display the data, a magnetically shielded room for interference reduction, a patient table for subject/patient support, and a gantry for articulation of the upper sensor.

(5) Intended Uses:
"The Magnes II Biomagnetometer is intended for use in diagnostic procedures that require the measurement and display of extracranial magnetic fields and information about the electrical activity of the brain as inferred from those fields."

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(6) Technological Characteristics:

The Magnes II biomagnetometer system provides a second magnetic field sensor unit but is otherwise equivalent to the standard Magnes Biomagnetometer system.

The same electrical currents in the brain that produce electric voltages on the body surface also produce magnetic fields orthogonal to those currents. The magnetic fields are mathematically related to the electrical currents and voltages by the classical electromagnetic field equations of Maxwell, Lenz, and others.

The major technological difference between the Magnes II Biomagnetometer and conventional electrical signal devices (EEG) is the use of superconducting magnetic field sensors. The magnetic field sensor detects and converts magnetic field energy to electrical signals without patient electrical contact. The electronic and computer subsystems are equivalent to processing systems in use by electrical signal devices.

(b) (1) Nonclinical Tests and Results:

Nonclinical tests involve verification of basic physical principles associated with the technology. Typical examples are tests using "phantom" signal sources for localization accuracy, characterization of signal sensitivity, and system background noise relative to biomagnetic signals of interest.

Test results comparing the response of the second Magnes sensor relative to the original Magnes signal sensor indicate that there is no significant difference in the performance of the Magnes II Biomagnetometer system for the detection and display of biomagnetic signals.

(2) Conclusions:

The addition of the second sensor to the Magnes Biomagnetometer system provides additional simultaneous coverage area for signal acquisition and reduction of overall recording time.

Measurement, display, and interpretation of biomagnetic fields originating from electrical activity in the brain has been under development for at least the past 30 years. Current technology has produced enhanced capability through implementation of multiple signal sensors. The Magnes II Biomagnetometer system represents the latest implementation of this technology.

Any questions regarding the 510(k) summary may be directed to the contact person noted.

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