SOFTWARE VERSION 8.5CD OF THE MRT-35A MAGNETIC RESONANCE IMAGING SYSTEM

K961842 · Toshiba America Mri, Inc. · LNH · Aug 2, 1996 · Radiology

Device Facts

• Record ID: K961842
• Device Name: SOFTWARE VERSION 8.5CD OF THE MRT-35A MAGNETIC RESONANCE IMAGING SYSTEM
• Applicant: Toshiba America Mri, Inc.
• Product Code: LNH · Radiology
• Decision Date: Aug 2, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 892.1000
• Device Class: Class 2

Intended Use

Anatomical Region: Head, body, extremity, spine, neck, TMJ, Knee Nuclei excited: Hydrogen Diagnostic Use: 2D and 3D imaging, Contrast Media, MR Vascular Imaging

Device Story

The MRT-35A Upgrade 8.5CD is a software enhancement for the existing 0.35 Tesla superconductive MRI system. It introduces a 2D Time-of-Flight (TOF) sequence for vascular imaging and improves image reconstruction for Fast Spin Echo (FSE) sequences to reduce acquisition artifacts. The device operates by acquiring MR signals via 2D multislice, multiecho, or 3DFT modes, which are then processed using Fourier reconstruction techniques. The system is operated by trained clinical staff in a radiology setting. The output consists of 512x512 matrix images displayed for physician review. These images assist clinicians in diagnosing anatomical structures and vascular conditions. The upgrade benefits patients by providing improved image quality and specialized vascular imaging capabilities without requiring hardware changes.

Clinical Evidence

Bench testing included phantom imaging to evaluate signal-to-noise ratios for all new sequences. Clinical studies were presented to demonstrate image quality improvements for the new 2D TOF sequence and the updated FSE reconstruction software. No specific sensitivity, specificity, or AUC metrics were reported.

Technological Characteristics

0.35 Tesla superconductive magnet; 2D/3D Fourier reconstruction; 512x512 display matrix; supports spin echo, inversion recovery, FSE, and 2D TOF sequences. Software-based image reconstruction and filtering. No hardware changes from 8.0CD.

Indications for Use

Indicated for diagnostic 2D and 3D magnetic resonance imaging of the head, body, extremities, spine, neck, TMJ, and knee, utilizing hydrogen nuclei and contrast media, including MR vascular imaging.

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

• MRT-35A 8.0CD Software release

Submission Summary (Full Text)

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Toshiha America MR1, Inc.
8.5CD 510(k) Application

APPENDIX A

510(k) SUMMARY

K961842

AUG - 2 1996

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# 510(k) Summary

1. Model Name: MRT-35A
Device Name: Magnetic Resonance Device Accessory
Trade/Proprietary Name: MRT-35A Upgrade 8.5CD

2. Establishment Registration: #2936923

3. Name and Address: TOSHIBA AMERICA MRI, INC.
280 Utah Avenue
South San Francisco, CA 94080

Contact Person: Steven M. Kay
[phone]

4. DATE OF SUBMISSION: 26 April 1996

5. DEVICE DESCRIPTION

The 8.5CD Upgrade for MRT-35A adds a new sequence and software enhancements to the existing MRT-35A software version.

5A. DEVICE CHARACTERISTICS:

The following describes the MRT-35A system with the 8.5CD Upgrade.

| Type of magnet | Superconductive |
| --- | --- |
| Static Field | 0.35 Tesla |
| Type of RF Coil | Not applicable |
| Data Acquisition Mode | 2D Multislice, Multiecho, 3DFT |
| Pulse sequences | Spin echo, Inversion recovery, Fast spin echo, Cardiac Gated, Partial Flip, Matched Bandwidth, 3D, inplane presaturation, Spectre, Angiography, 2D Time-of-Flight. |
| Reconstruction Technique | 2 Dimensional Fourier
3 Dimensional Fourier
3 Dimensional Slice shift, Oblique, MIP for Angio |
| Display Matrix: | 512x512 |
| Slice Selection method: | Selective gradient, "slab" select slice encode for 3D |
| Acquisition Matrix: | 256x32 to 256x256 in steps of 1 |
| Image Acquisition Time: | 3 seconds for fluoro acquisitions typical, 6 minutes for 4 NEX FSE typical |
| Pre and Post Processing: | No baseline correction except for data conjugation of Advanced Fourier Imaging, Post processing filtering |
| Number of slices: | 64 for 3D acquisitions, protocol file limit of 256 slices |
| Slice Orientation: | unrestricted |
| Spacing: | gapless imaging |

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# 5A.1 New Hardware and Hardware Changes

Version 8.5CD does not change the configuration of hardware for the MRT-35A.

# 5A.2 New Software Features

Version 8.5CD does not introduce new software features to the MRT-35A.

# 5A.3 New Sequences and Sequence Changes

## 5A.3.1 2D Time of Flight(TOF) sequence

The 8.5CD upgrade provides a 2DTOF sequence. 2DTOF includes optional walking presat (superior or inferior) to reduce the signal from adjacent tissue due to motion. The user interface for sequence selection and parameter specification common to other sequences is supported for 2DTOF also. There is no exceptional change in the manner that 2DTOF is selected when compared to pre-existing sequences. Acquisition orientation is restricted to transaxial orientation only. The sequence will not support oblique orientations nor gated acquisitions.

## 5A.3.2 Sequence specification summary

The new 2DTOF sequence, with its identification parameters, is given below. With the exception of this additional sequence, there is no change to the sequence software.

| Seq # | Sequence Type | TE | Flow Comp | Min Thick 8.5CD | Difference from 8.0CD |
| --- | --- | --- | --- | --- | --- |
| 27 | 2D ANGIO TOF | 12 | FC | 2.0mm | NEW |

# 6. SAFETY PARAMETERS

Maximum static field strength: 0.35 Tesla

Rate of change of magnetic field: 6.83 Tesla/sec Axial
6.69 Tesla/sec Transverse

Radio frequency power deposition: 0.34 W/kg

Acoustic Noise levels: L-peak: 101.6 db (peak impulse sound pressure)
L-eq: 86.5 db (time integral of a-weighted sound pressure)

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# 7. IMAGING PERFORMANCE PARAMETERS

| Specification volume | 10 Cm dsv for head coil |
| --- | --- |
| | 20 Cm dsv for body coil |
| Signal to noise: | Sample phantom images and clinical images were presented for all new sequences. Signal-to-noise ratios for each phantom image was given. Clinical studies were presented for all new sequences. |
| Uniformity in three orthogonal planes | Not Applicable |
| Slice Profile in three orthogonal planes | Not Applicable |
| Geometric Distortion in three orthogonal planes | Not Applicable |
| Slice Thickness | 0.8 mm to limits of FOV and sequence. |
| Interslice Spacing | 0 mm minimum |

# 8. Intended Use

Anatomical Region: Head, body, extremity, spine, neck, TMJ, Knee
Nuclei excited: Hydrogen
Diagnostic Use: 2D and 3D imaging, Contrast Media, MR Vascular Imaging

# 9. Equivalency Information

8.5CD Upgrade for MRT-35 is substantially equivalent to the 8.0CD Software release for MRT-35. Similarity and/or differences between this device and the predicate device are summarized below.

# HARDWARE ENHANCEMENTS

8.5CD has no hardware component differences from the preceding MRT-35A upgrade, 8.0CD.

# SOFTWARE ENHANCEMENTS

| Technical | Clinical |
| --- | --- |
| Improved Image Reconstruction for FSE
Image reconstruction software is provided to further reduce subtle acquisition artifacts previously found in TE=20 Fast Spin Echo (FSE) sequences. | Image quality is improved for Fast Spin Echo TE=20 (4 and 7 echo). |

# SEQUENCE ENHANCEMENTS

| Technical | Clinical |
| --- | --- |
| 2D Time-Of-Flight (TOF) Sequence
A new 2DTOF sequence is provided with optional pre-saturation bands that are user selected. | Allows image acquisitions of vascular structures with reduced motion artifacts. |