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 Description

The AIRIS Operating System Software is revised to Version 4 to increase the clinical utility of the AIRIS in the stationary configuration. The MRP-7000 Operating System Software is revised to Version 4 to increase the clinical utility of the MRP-7000 in both stationary and mobile configurations.

Version 4 Operating System revisions include automatic per patient RF Gain calibration for improved fat suppression, daily- or per-patient x- y- and z-axis gradient offsets for regional shimming, MR cholangiography sequences (MRCP) for improved imaging of the biliary tract, Fluoroscopic MR imaging sequences for 'nearreal-time' imaging, FLAIR (fast low-angle inversion recovery) sequence for suppression of CSF signal, segmented K-space SARGE sequence for time-improved cardiac imaging, addition of rephasing to several FSE sequences, addition of RS (RF Spoiled) SARGE sequence, improved method for body return artifact rejection, submillimeter slice thickness for 3DTOFMRA sequences, reduced slice interval for 3D TOF/GE/SARGE/SE acquisitions, high-definition imaging by 512 matrix reconstruction, short TE SE sequences (TE=9, 10ms), addition of rephasing to 3D SARGE sequence, 'whole echo' 3DTOFMRA, non-linear window for MRA, brightness normalization for selected images with the same acquisition parameters within a patient study, and ACR/NEMA/DICOM 3 support.

In addition, the MRP-7000 and AIRIS Operating System Software are modified to change the maximum SAR limit from 0.4 W/kg to 1.0 W/kg as permitted under the International Electrotechnical Commission (IEC) standard Part 2: Particular Requirements for the Safety of Magnetic Resonance Equipment for Medical Diagnosis.

AI/ML Overview

This document describes the 510(k) premarket notification for the Hitachi Version 4 Operating System Software for AIRIS and MRP-7000 MRI devices. The primary focus of the submission is to increase the maximum Specific Absorption Rate (SAR) limit from 0.4 W/kg to 1.0 W/kg, aligning with the International Electrotechnical Commission (IEC) standard Part 2: Particular Requirements for the Safety of Magnetic Resonance Equipment for Medical Diagnosis. The submission also details various software revisions to enhance clinical utility.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are not explicitly defined in terms of specific performance metrics (e.g., accuracy, sensitivity, specificity) for the imaging capabilities. Instead, the primary "acceptance criterion" addressed in this 510(k) is the compliance with a higher SAR limit based on an internationally recognized safety standard. The device's "performance" in this context refers to its ability to operate safely at the higher SAR level.

Acceptance Criteria (Implicit)	Reported Device Performance
Safety: Compliance with IEC-601-2-33 standard for SAR, specifically permitting a maximum SAR of 1.0 W/kg for the general patient population, derated from 1.5 W/kg due to absence of bore temperature/humidity sensors to 1.0 W/kg.	Hitachi proposes limiting SAR control for MRP-7000 and AIRIS MRI systems to a maximum of 1.0 W/kg, up from the previous 0.4 W/kg limit, to comply with the NORMAL OPERATING MODE defined in the IEC standard. The devices were originally cleared at 0.4 W/kg and this change leverages the new international safety standard.
Functional Equivalence: The software revisions maintain or improve the clinical utility of the device and do not introduce new safety concerns compared to the predicate device.	The Version 4 Operating System software includes numerous revisions to increase clinical utility (e.g., improved fat suppression, new imaging sequences like MRCP, FLAIR, SARGE, high-definition imaging, ACR/NEMA/DICOM 3 support). The device's technological characteristics are stated as "Identical to the Predicate Device" in Section 5.0, implying that the fundamental imaging principles and intended use remain the same, with enhancements rather than fundamental changes impacting safety or effectiveness.
Intended Use: The device continues to meet the intended use for MR systems as an imaging device to provide physiological and clinical information by displaying internal structures of the head, body, and extremities, based on proton density, T1, T2, and flow.	The stated "Indications for Use" (Section 6.0) are identical to those in Section 4.0, which describe the standard intended use of an MR system, including anatomical regions, excited nucleus, diagnostic uses (2D T1/T2-weighted imaging, T1/T2/proton density measurements, MR Angiography, image processing), and imaging capabilities. This remains consistent with the predicate.

2. Sample Size Used for the Test Set and the Data Provenance

The document does not describe a specific test set or clinical study with a defined sample size for evaluating the Version 4 Operating System Software or the change in SAR limit.

The data provenance for the SAR limit change is based on the International Electrotechnical Commission (IEC) standard IEC-601-2-33. The submission references an existing international standard and the FDA's supposed acceptance of its provisions, rather than presenting new clinical or performance data from a specific study.

For the new software features, the document states they "increase the clinical utility" and are revisions to existing systems. There is no mention of specific sample sizes or data provenance for proving the efficacy or performance of these new features. It's implied that these are incremental improvements to an already cleared device, not requiring new clinical performance studies for their functionality.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts

This information is not provided in the document. As there is no described test set or clinical study to evaluate the device's diagnostic performance for which ground truth would need to be established, this detail is absent. The submission primarily focuses on safety compliance (SAR limit) and functional enhancements to an existing device rather than diagnostic accuracy.

4. Adjudication Method for the Test Set

This information is not applicable as no specific test set requiring adjudication is described in the document.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs without AI Assistance

This information is not applicable and no such study was performed or is mentioned. The device in question is an MRI system's operating software, not an AI-assisted diagnostic tool.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

This information is not applicable. The device is an MRI system's operating software, which requires human operation and interpretation. It is not an algorithm that would typically be evaluated in a standalone performance study in the context of diagnostic accuracy. The "algorithm-only" aspect mentioned refers to the safety calculation for SAR, which is part of the system's inherent design and safety features, not a diagnostic algorithm.

7. The Type of Ground Truth Used

For the primary claim concerning the SAR limit increase, the "ground truth" used is the IEC-601-2-33 standard itself, which defines the safety parameters and acceptable SAR levels. This is a consensus-based international safety standard, rather than clinical outcomes or pathology data.

For the other software features, no specific ground truth is mentioned, as no formal performance testing in the conventional sense (e.g., against pathology) is described for these enhancements. The improvements in "clinical utility" would likely be assessed through engineering verification and validation against design specifications and potentially internal clinical evaluations, but not a large-scale ground truth study.

8. The Sample Size for the Training Set

This information is not applicable and not provided. The document describes an update to an MRI system's operating software and a change in its SAR limit. This is not a machine learning or AI-driven device that requires a training set in the typical sense for image interpretation or diagnosis.

9. How the Ground Truth for the Training Set Was Established

This information is not applicable as no training set for a machine learning model is described.

Summary

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SUBMITTER INFORMATION: 1.0

Hitachi Medical Systems America 1.1 Submitter: 1963 Case Parkway Twinsburg, OH 44087 PH: 216 425-1313 FX: 216 425-1410
James Jochen Rogers 1.2 Contact:
April 4, 1997 1.3 Date:

2.0 DEVICE NAME:

2.1 Magnetic Resonance Diagnostic Device
System, Nuclear Magnetic Resonance Imaging 2.2 Classification Name:
2.3 90LNH Classification Number:
Version 4 Operating System Software 2.4 Trade/Proprietary Name:

2.5 PREDICATE DEVICE(s):

Hitachi AIRIS with Version 3.7 Operating System Software Hitachi MRP-7000 with Version 3.7 Operating System Software

DEVICE DESCRIPTION: 3.0

FUNCTION 3.1
The AIRIS Operating System Software is revised to Version 4 to increase the clinical utility of the AIRIS in the stationary configuration. The MRP-7000 Operating System Software is revised to Version 4 to increase the clinical utility of the MRP-7000 in both stationary and mobile configurations.

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Because of the recent approval of the IEC-601-2-33 standard on MR safety, Hitachi seeks to take advantage of the acceptance of the higher SAR level permitted under that standard for the general patient population. We believe that the FDA has accepted the provisions of the IEC standard with respect to its SAR requirements, in compliance, we interpret the FDA's position with regard to the IEC standard for SAR as superceding its previous limit for SAR (up to 0.4 W/kg whole body is of no concern), and no further evidence is necessary beyond that given in the IEC standard and its rationale.

The Hitachi MRP-7000 and AIRIS MR Devices were originally cleared for marketing with an SAR limit of 0.4 W/kg (K9903318 [MRP-7000], and K945155 [AIRIS]), in compliance with the FDA's August 2, 1988 "Guidance for the Content and Review of a Magnetic Resonance Diagnostic Device 510(k) Application". In the FDA guidance, Safety Parameter Action Levels limit SAR to ≤ 3.2 W/kg averaged over the head, to ≤ 0.4 W/kg whole body, or to demonstrate that exposure to RF fields is insufficient to produce a core temperature increase in excess of 1℃ and localized heating greater than 38°C in the head. 39°C in the trunk, and 40°C in the extremities.

The IEC standard, in defining the NORMAL OPERATING MODE, allows SAR values up to 1.5 W/kg under conditions of favorable environmental conditions ( a scan room temperature < 24°C, scan room relative humidity < 60%). However, the IEC standard dictates that maximum SAR values be derated up to a floor value of 1.0 W/ kg for scan room temperature and humidity above these baseline environmental conditions, provided these ambient conditions are consistent with the overall device operating specifications. Since the MRP-7000 and AIRIS do not presently have bore temperature or humidity sensors, maximum SAR is derated to a maximum of 1.0 W/ kg. In order to comply with the NORMAL OPERATING MODE defined in the IEC standard, we at Hitachi propose that SAR control for the MRP-7000 and AIRIS MRI systems be !imited to a maximum of 1.0 W/kg, from the current limit of 0.4 W/kg

No marketing claims will be made for the MRP-7000 and AIRIS stating compliance with the IEC standard. A separate future 510(k) premarket notification will describe full implementation of the IEC standard with respect to control of SAR, including, 1) the three operating modes (normal, first-level, and second-level, operating modes) as defined in the IEC standard, 2) modified clinical user interface through visual screens, and 3) control of access to the upper operating modes. However, the IEC standard permits operation of an MR device entirely within the NORMAL OPERATING MODE without any of these features.

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

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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 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 submillisecond 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.

DEVICE INTENDED USE: 4.0

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Head, Body, Spine, Extremities Anatomical Region: .
. Nucleus excited: Proton
- 2D T1- / T2-weighted imaging Diagnostic uses:
  - T1, T2, proton density measurements
  - MR Angiography
  - image processing
2D, 3D Spin Echo (SE) ● Imaging capabilities:
- 2D Fast Spin Echo (FSE); also with rephasing
- 3D Fast Spin Echo (FSE)
- 2D, 3D Fast Inversion Recovery (FIR)
- 2D,3D Gradient Field Echo (GE); also with rephasing (GR)
- 2D Steady state acquisition with rewinded GE (SARGE)
- 3D Steady state acquisition with rewinded GE (SARGE); also with rephasing
- 2D Dual Slice acquisition (DS)
- MR Angiography (2D TOF, 3D TOF, half echo, high resolution/high definition, sloped slab profile, magnetization transfer contrast)
- RF Coil Uniformity
- Adaptive Image post-processing

DEVICE TECHNOLOGICAL CHARACTERISTICS: 5.0

Identical to the Predicate Device.

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Image /page/5/Picture/0 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a stylized caduceus symbol, which is a staff with two snakes coiled around it, and the text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" arranged in a circular fashion around the symbol. The text is in all caps and appears to be in a sans-serif font. The logo is black and white.

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

James Jochen Rogers Manager, Regulatory Affairs Hitachi Medical Systems America, Inc. 1963 Case Parkway® Twinsburg, OH 44087

JUL - 3 1997

Re: K971279 Version 4 Software for AIRIS/MRP-7000 (MRI) Dated: April 4, 1997 Received: April 7, 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, 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 misbranion.

If your device is classified (see above) into either 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 requirement, as set forth in the Quality System Regulation (OS) 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 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 (301) 594-4613. Additionally, for question and advertising of your device, please contact the Office of Compliance at (301) 594-4639. 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 (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsmamain.html".

Sincerely yours.

h. Niau Yu.

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): Kg 7 1279

Device Name: Version 4.0 Operating System Software (AIRIS, MRP-7000)

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 crosssectional 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.

Head, Body, Spine, Extremities Anatomical Region:
Proton Nucleus excited:
2D T1- / T2-weighted imaging Diagnostic uses:
- T1, T2, proton density measurements
- MR Angiography image processing
Imaging capabilities:
2D, 3D Spin Echo (SE)
2D Inversion Recovery (IR)
2D Fast Spin Echo (FSE); also with rephasing
3D Fast Spin Echo (FSE)
2D, 3D Fast Inversion Recovery (FIR)
2D,3D Gradient Field Echo (GE); also with rephasing (GR)
2D Steady state acquisition with rewinded GE (SARGE)
3D Steady state acquisition with rewinded GE (SARGE); also with rephasing
2D Dual Slice acquisition (DS)
MR Angiography (2D TOF, 3D TOF, half echo, high resolution/high definition, sloped slab profile, magnetization transfer contrast) RF Coil Uniformity

Adaptive Image post-processing

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Concurrence of CDRH, Office of Device Evaluation (ODE)

Oliont le. Seymon

(Division Sign-Off) Division of Reproductive, Abdominal, ENT. and Radiological Devices 510(k) Number

Prescription Use (Per 21 CFR 801-109

Over-the-Counter Use .

(Optional Format 1-2-96)

Regulation Number and Section

§ 892.1000 Magnetic resonance diagnostic device.

(a)
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).(b)
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.