EPI-II SYSTEM OPTION W/HIGH PERFORMANCE GRADIENTS

K954646 · Philips Medical Systems (Cleveland), Inc. · LNH · Jan 18, 1996 · Radiology

Device Facts

• Record ID: K954646
• Device Name: EPI-II SYSTEM OPTION W/HIGH PERFORMANCE GRADIENTS
• Applicant: Philips Medical Systems (Cleveland), Inc.
• Product Code: LNH · Radiology
• Decision Date: Jan 18, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 892.1000
• Device Class: Class 2

Intended Use

The Picker International EDGE system is indicated for use as a NMR device that produces images that: (1) correspond to the distribution of protons exhibiting NMR, (2) depend upon the NMR parameters (proton density, flow velocity, spin-lattice relaxation time (T1), and spin-spin relaxation time (T2)) and (3) display the soft tissue structure of the head and whole body. When interpreted by a trained physician, these images yield information that can be useful in the determination of a diagnosis.

Device Story

EPI-II System Option is an upgrade for Picker EDGE MRI systems; provides higher gradient output power for faster imaging or higher spatial resolution. Components include water-cooled non-resonant self-shielded gradient coils and high-performance gradient amplifiers. Device utilizes single-shot echo-planar imaging (EPI) sequences and modified standard sequences. Operated by trained clinical staff in an MRI suite. System includes a software algorithm to monitor dB/dt levels (warning at >40 T/s, prohibiting >60 T/s) and SAR levels to ensure patient safety. Output consists of MR images interpreted by physicians for diagnostic purposes. Benefits include reduced scan times and improved image resolution compared to standard EDGE systems.

Clinical Evidence

Bench testing only. Comparison of gradient performance (strength, slew rate), acoustic noise levels, and safety parameters (dB/dt, SAR) against predicate EDGE system. No clinical data provided.

Technological Characteristics

Water-cooled, non-resonant, self-shielded gradient coils; gradient amplifiers (270 A RMS, 440 A peak, 600 V max); max gradient strength 27 mT/m; max slew rate 72 mT/m/msec. Software-based dB/dt monitoring algorithm and SAR control. Operates at 63.75 MHz proton resonance.

Indications for Use

Indicated for MR imaging of head and whole body soft tissue structures to assist physician diagnosis based on proton density, flow velocity, T1, and T2 parameters.

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

• EDGE system (K931544)
• EPI-I software option (K945828)

Submission Summary (Full Text)

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SUMMARY OF SAFETY AND EFFECTIVENESS

I. General Information

Classification: Class II
Magnetic Resonance (MR) Imaging System

Common/Usual Name: MRI System Option

Proprietary Name: EPI-II System Option with High Performance Gradients

Establishment Registration: Picker International, Inc.
World Headquarters
595 Miner Road
Cleveland, Ohio 44143
FDA Owner Number: #1580240
FDA Registration Number: #1525965

Performance Standards: Not applicable

2. Intended Uses:
The EPI-II System Option with High Performance Gradients is designed to provide higher gradient output power in order to allow the user to acquire images at a faster rate or acquire images with a higher spatial resolution than would normally be possible with a standard EDGE system with the EPI-I software option. The indications for use are the same as for standard MR imaging.

3. Device Description:
The EPI-II System Option with High Performance Gradients consists of water-cooled non-resonant self-shielded gradient coils, high performance gradient amplifiers, single-shot echo-planar sequences, and modified standard sequences.

PICKER INTERNATIONAL, INC. (EPI-II) (10/9/95) I-1

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# 4. Safety and Effectiveness

## a. Safety

As shown in the chart below, the Picker EPI-II System Option with High Performance Gradients for an EDGE system is identical to the standard EDGE system using the EPI-I multi-shot software option except for the dB/dt operating levels and software algorithm.

SAFETY CHART

| Parameter | EDGE with EPI-II System Option | EDGE with EPI-I Software Option |
| --- | --- | --- |
| Static Magnetic Field
Corresponding to proton resonance of 63.75 MHz (EDGE). | Same | Same |
| Time Varying Magnetic Field | Total dB/dt software algorithm warns when operational level is above 40 T/s and prohibits operation above 60 T/s (as measured by method in FDA's draft guidance document). | Not to exceed 20 T/s (as measured according to method in IEC 601-2-33). |

PICKER INTERNATIONAL, INC. (EPI-II) (10/9/95)

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| Parameter | EDGE with EPI-II System Option | EDGE with EPI-I Software Option |
| --- | --- | --- |
| Radio Frequency Absorption

Power deposition during imaging is limited by the SAR algorithm to a maximum value of:

1.2 W/kg NORMAL OPERATING MODE
2.4 W/kg FIRST LEVEL CONTROLLED OPERATING MODE
> 2.4 W/kg SECOND LEVEL CONTROLLED OPERATING MODE
(Requires human studies protocol approval according to local requirements.) | Same | Same |
| Acoustic Noise | Acoustic noise levels of EPI-II System Option under worst case conditions are: 109.1 dBA (average) and 119.5 dB (peak). | Acoustic noise levels of standard EDGE system under worst case conditions are: 118.7 dBA (average) and 127.8 dB (peak). |

PICKER INTERNATIONAL, INC. (EPI-II) (10/9/95)

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| Parameter | EDGE with EPI-II System Option | EDGE with EPI-I Software Option |
| --- | --- | --- |
| Intended Use:
The Picker International EDGE system is indicated for use as a NMR device that produces images that:
(1) correspond to the distribution of protons exhibiting NMR, (2) depend upon the NMR parameters (proton density, flow velocity, spin-lattice relaxation time (T1), and spin-spin relaxation time (T2)) and (3) display the soft tissue structure of the head and whole body. When interpreted by a trained physician, these images yield information that can be useful in the determination of a diagnosis. | Same | Same |

## b. Effectiveness

Compared to the standard EDGE system using the EPI-I software option (see 510(k)s K931544 and K945828), the EPI-II System Option has a gradient system which is able to produce higher gradient operational levels and provide faster scanning capability. The EPI-II System Option also includes EPI single shot sequences.

PICKER INTERNATIONAL, INC. (EPI-II) (10/9/95)

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# EFFECTIVENESS CHART

| Parameter | EPI-II System Option | Predicate |
| --- | --- | --- |
| Gradient Coil Design | Water-cooled, high performance, self-shielded non-resonant gradient system. | Basic EDGE system uses a standard performance, air cooled, self-shielded gradient system. (see 510(k) K931544). |
| Gradient Power | Gradient Amplifiers: 270 A RMS, 440 A peak, 600 V max. | Gradient Amplifiers: 135 A RMS, 220 A peak, 350 V max. (see 510(k) K931544) |
| Gradient Performance | Maximum Gradient Strength = 27 mT/m
Maximum Slew Rate = 72 mT/m/msec | Maximum Gradient Strength = 16 mT/m
Maximum Slew Rate = 25 mT/m/msec |
| Fast Scanning Sequences | Single-shot EPI fast scanning sequences. Entire image collected following a single RF excitation using multiple gradient recalled echoes. | Multi-Shot EPI fast scanning sequences. A number of RF excitations are required to collect an entire image. Multiple gradient recalled echoes used to collect data. (see 510(k) K945828) |
| EPI Data Correction | Interactive prescan process. | Automated process which does not require operator involvement. (see 510(k) K945828) |
| IR Prep Pulse | Improves T_{1} image contrast. | Same. (see 510(k) K945828). |
| Standard Imaging Sequences | Increased image resolution or redesigned for: shorter inter-echo spacing; shorter echo times; and/or increase motion artifact suppression. | Standard image resolution, inter-echo spacing, echo times, and motion artifact suppression, limited by the lower output power of the gradient system. |

PICKER INTERNATIONAL, INC.
(EPI-II)
(10/9/95)
I-5