STRATIS II

K974498 · Hitachi Medical Systems America, Inc. · LNH · Feb 26, 1998 · Radiology

Device Facts

• Record ID: K974498
• Device Name: STRATIS II
• Applicant: Hitachi Medical Systems America, Inc.
• Product Code: LNH · Radiology
• Decision Date: Feb 26, 1998
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 892.1000
• Device Class: Class 2

Intended Use

The MR system is an imaging device, and is intended to provide the physician with physiological and clinical information, obtained non-invasively and without the use of ionizing radiation. The MR system produces transverse, coronal, sagittal, oblique, and curved cross-sectional images that display the internal structure of the head, body, or extremities. The images produced by the MR system reflect the spatial distribution of protons (hydrogen nuclei) exhibiting magnetic resonance. The NMR properties that determine the image appearance are proton density, spin-lattice relaxation time (T1), spin-spin relaxation time (T2), and flow. When interpreted by a trained physician, these images provide information that can be useful in diagnosis determination.

Device Story

STRATIS II is a system-level upgrade for the Hitachi STRATIS MR diagnostic device. It functions as a stationary, stand-alone imaging system. Input consists of RF emissions from hydrogen nuclei excited by magnetic fields and spatial localization via magnetic field gradients. The system transforms these signals into 2D/3D cross-sectional images using reconstruction algorithms. Enhancements include a workstation-based User Console with a graphical user interface (OpenWindows™), real-time system control, and new acquisition sequences (TRSG, RSSG). Hardware additions include an elliptical T/R QD Body Coil, physiological gating, and phased-array RF coils. Operated by trained clinicians in a clinical setting, the device provides images for physician interpretation to assist in diagnosis. Benefits include high-quality anatomical imaging without ionizing radiation.

Clinical Evidence

No clinical data provided; bench testing only.

Technological Characteristics

Magnetic resonance diagnostic device; proton excitation; RF frequencies up to 65MHz; pulse powers up to >10kW; gradient fields sub-millisecond to milliseconds. Features elliptical T/R QD Body Coil, phased-array RF coils, and physiological gating. Software-based workstation console (OpenWindows™). Stand-alone configuration.

Indications for Use

Indicated for non-invasive diagnostic imaging of the head, body, spine, and extremities in patients requiring visualization of internal structures via proton density, T1, T2, and flow-based MR imaging. Contraindications not specified.

Regulatory Classification

Identification

A magnetic resonance diagnostic device is intended for general diagnostic use to present images which reflect the spatial distribution and/or magnetic resonance spectra which reflect frequency and distribution of nuclei exhibiting nuclear magnetic resonance. Other physical parameters derived from the images and/or spectra may also be produced. The device includes hydrogen-1 (proton) imaging, sodium-23 imaging, hydrogen-1 spectroscopy, phosphorus-31 spectroscopy, and chemical shift imaging (preserving simultaneous frequency and spatial information).

Special Controls

*Classification.* Class II (special controls). A magnetic resonance imaging disposable kit intended for use with a magnetic resonance diagnostic device only is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.

Predicate Devices

• Hitachi STRATIS
• Hitachi STRATIS with Version 6-05 Operating System Software

Submission Summary (Full Text)

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FEB 26 1998
K974498

1.0 SUBMITTER INFORMATION:

1.1 Submitter: Hitachi Medical Systems America
1963 Case Parkway
Twinsburg, OH 44087
PH: 216 425-1313
FX: 216 425-1410

1.2 Contact: James Jochen Rogers
1.3 Date: November 26, 1997

2.0 DEVICE NAME:

2.1 Classification Panel: Radiology
2.2 Classification Number: 892.1000 Magnetic Resonance Diagnostic Device
2.3 Product Nomenclature: System, Nuclear Magnetic Resonance Imaging
2.4 Product Code(s): 90LNH
90MOS (Magnetic Resonance Specialty Coil)
2.5 Trade/Proprietary Name: STRATIS II
2.6 PREDICATE DEVICE(s):
Hitachi STRATIS
Hitachi STRATIS with Version 6-05 Operating System Software

3.0 DEVICE DESCRIPTION:

3.1 FUNCTION

The STRATIS Magnetic Resonance Diagnostic Device is being enhanced by the STRATIS II System-level upgrade to increase the clinical utility of the STRATIS in the stationary configuration. The STRATIS II is provided in a stand-alone configuration, and as an upgrade path to existing STRATIS installations.

STRATIS II System-level upgrade enhancements include a new Back End user interface featuring a workstation-based User Console, implementing a graphical user interface operating system and task card-style operations (OpenWindows™). A new Front End provides real-time system control, data acquisition and reconstruction, implements all image acquisition sequences available on current STRATIS, and provides two additional types of image acquisition sequences: TRSG (time-reversed steady-state acquisition with rewinded gradient echo) and RSSG (rf spoiled steady-state acquisition with rewinded gradient echo). Other enhancements include an elliptical T/R QD Body Coil, a patient physiological gating package, and phased-array RF coils.

3.2 SCIENTIFIC CONCEPTS

Magnetic Resonance (MR) is based on the fact that certain atomic nuclei have electromagnetic properties which cause them to act as small spinning bar magnets. The most ubiquitous of these nuclei is hydrogen, which makes it the primary nucleus used in current imaging experiments in magnetic resonance. When placed in a magnetic field, there is a slight net orientation or alignment of these atomic nuclei with the magnetic field. The introduction of a short burst of radiofrequency (RF) excitation of wavelength specific to the magnetic field strength and to the atomic nuclei under consideration can cause a reorientation of the proton's magnetization vector. When the RF excitation is

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removed, the proton relaxes and returns to its original orientation. The rate of relaxation is exponential, and varies with the character of the proton and its adjacent molecular environment. This reorientation process is characterized by two exponential relaxation times called T1 and T2 which can be measured.

These relaxation events are accompanied by an RF emission or echo which can be measured and used to develop a representation of these emissions on a three dimensional matrix. Spatial localization is encoded into the echo by varying the RF excitation and by appropriately applying magnetic field gradients in x, y, and z directions, and changing the direction and strength of these gradients. Images depicting the spatial distribution of NMR characteristics of the nuclei under consideration can be constructed by using image processing techniques similar to those used in CT.

For magnetic fields up to 1.5T, the RF frequencies commonly used range up to 65MHz. The RF fields have pulse powers from several watts to greater than 10 kilowatts, and repeat at rates from once every few seconds to greater than fifty per second. The time-varying magnetic gradient fields have a typical duration of sub-millisecond to several milliseconds.

## 3.3 PHYSICAL AND PERFORMANCE CHARACTERISTICS

MR is currently of great interest because it is capable of producing high quality anatomical images without the associated risks of ionizing radiation. In addition, the biological properties that contribute to MR image contrast are different from those responsible for x-ray image contrast. In x-ray imaging, differences in x-ray attenuation, largely based on differences in electro density are responsible for the contrast observed in x-ray images. In MR imaging, differences in proton density, blood flow, and relaxation times T1 and T2 all may contribute to image contrast. In addition, by varying the duration and spacing of the RF pulses, images may be produced in which the contrast is primarily dependent on T1 relaxation, T2 relaxation, proton density, or a combination of all three.

## 4.0 DEVICE INTENDED USE:

The MR system is an imaging device, and is intended to provide the physician with physiological and clinical information, obtained non-invasively and without the use of ionizing radiation. The MR system produces transverse, coronal, sagittal, oblique, and curved cross-sectional images that display the internal structure of the head, body, or extremities. The images produced by the MR system reflect the spatial distribution of protons (hydrogen nuclei) exhibiting magnetic resonance. The NMR properties that determine the image appearance are proton density, spin-lattice relaxation time (T1), spin-spin relaxation time (T2), and flow. When interpreted by a trained physician, these images provide information that can be useful in diagnosis determination.

- Anatomical Region: Head, Body, Spine, Extremities
- Nucleus excited: Proton
- Diagnostic uses:
- 2D T1- / T2-weighted imaging
- T1, T2, proton density measurements
- MR Angiography
- image processing
- Imaging capabilities:
- 2D, 3D Spin Echo (SE)
- 2D, 3D Fast Spin Echo (FSE)
- 2D Inversion Recovery (IR)
- 2D, 3D Fast Inversion Recovery (FIR)
- 2D, 3D Gradient Echo (GE)
- 2D, 3D Steady state acquisition with rewinded GE (SARGE)

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2D, 3D RF-spoiled SARGE (RSSG)
2D, 3D Time-reversed SARGE (TRSG)
MR Angiography
2D, 3D TOF
2D, 3D TOF RSSG
ECG, Peripheral Gating
Fat Suppression

## 5.0 DEVICE TECHNOLOGICAL CHARACTERISTICS:
Identical to the Predicate Device.

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DEPARTMENT OF HEALTH & HUMAN SERVICES
Public Health Service
FEB 26 1998
Food and Drug Administration
9200 Corporate Boulevard
Rockville MD 20850

James Jochen Rogers
Manager, Regulatory Affairs
Hitachi Medical Systems America
1959 Summit Commerce Park
Twinsburg, OH 44087-2371

Re: K974498
STRATIS II (Magnetic Resonance Diagnostic Device)
Dated: November 26, 1997
Received: November 28, 1997
Regulatory class: II
21 CFR 892.1000/Procode: 90 LNH

Dear Mr. Rogers:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to 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). 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.

If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic QS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at [phone]. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at [phone]. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number [phone] or [phone] or at its Internet address "http://www.fda.gov/cdrh/dsma/dsmamain.html".

Sincerely yours,

Lillian Yin, Ph.D.
Director, Division of Reproductive,
Abdominal, Ear, Nose and Throat
and Radiological Devices
Office of Device Evaluation
Center for Devices and
Radiological Health

Enclosure

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510(k) Number (if known): _________________________

Device Name: STRATIS II

Indications for Use:

The MR system is an imaging device, and is intended to provide the physician with physiological and clinical information, obtained non-invasively and without the use of ionizing radiation. The MR system produces transverse, coronal, sagittal, oblique, and curved cross-sectional images that display the internal structure of the head, body, or extremities. The images produced by the MR system reflect the spatial distribution of protons (hydrogen nuclei) exhibiting magnetic resonance. The NMR properties that determine the image appearance are proton density, spin-lattice relaxation time (T1), spin-spin relaxation time (T2), and flow. When interpreted by a trained physician, these images provide information that can be useful in diagnosis determination.

- Anatomical Region: Head, Body, Spine, Extremities
- Nucleus excited: Proton
- Diagnostic uses:
- 2D T1- / T2-weighted imaging
- T1, T2, proton density measurements
- MR Angiography
- image processing
- Imaging capabilities:
- 2D, 3D Spin Echo (SE)
- 2D, 3D Fast Spin Echo (FSE)
- 2D Inversion Recovery (IR)
- 2D, 3D Fast Inversion Recovery (FIR)
- 2D, 3D Gradient Echo (GE)
- 2D, 3D Steady state acquisition with rewinded GE (SARGE)
- 2D, 3D RF-spoiled SARGE (RSSG)
- 2D, 3D Time-reversed SARGE (TRSG)
- MR Angiography
- 2D, 3D TOF
- 2D, 3D TOF RSSG
- ECG, Peripheral Gating
- Fat Suppression

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

Concurrence of CDRH, Office of Device Evaluation (ODE)

David A. Lyman
(Division Sign-Off)

Division of Reproductive, Abdominal, ENT, and Radiological Devices

510(k) Number K974498

Prescription Use ☑
(Per 21 CFR 801-109)

OR

Over-the-Counter Use ☐

(Optional Format 1-2-96)