(88 days)
The Siemens Diffusion-Weighted MR Imaging Package has been designed to image the diffusive mobility of water or other proton-containing molecules. One important clinical application is to visualize the apparent loss of mobility by water molecules in brain tissue affected by acute stroke. Areas of decreased diffusion, as is observed in acute cerebral infarcts, appear as areas of higher image intensity.
Diffusion weighted MR pulse sequences are more accurate than conventional MRI pulse scquences in identifying the occurrence of acute stroke during the first 24 hours after onset of symptoms.
Diffusion sensitivity has been added to the basic echo-planar pulse sequence by applying a large magnetic field gradient pulse before the 180 degree refocusing rf pulse and an identical gradient pulse after the 180 degree rf pulse.
The provided text describes the Siemens Diffusion Weighted MR Imaging Package (MAGNETOM Vision) and its 510(k) summary (K971055) from 1997. However, the document does not contain information about acceptance criteria, a study proving the device meets those criteria, or details regarding sample sizes, expert involvement, or adjudication methods.
The document primarily focuses on:
- General Information: Manufacturer, contact, date, and device name (Diffusion Weighted-MR Imaging/MAGNETOM Vision).
- Device Description: Technical explanation of how diffusion sensitivity is added to an echo-planar pulse sequence.
- Intended Use: Imaging diffusive mobility of water, with a specific mention of visualizing loss of mobility in brain tissue affected by acute stroke.
- Technological Characteristics: Notes that the system's core technology remains the same, with new sequences being added.
- General Safety and Effectiveness Concerns: Discusses the drawback of echo-planar imaging being sensitive to magnetic field inhomogeneities, leading to image distortion.
- Substantial Equivalence: States that the new Diffusion Weighted MRI Sequences are substantially equivalent to commercially available Echo Planar Sequences.
- FDA Response: The FDA letter confirms the device's substantial equivalence to pre-amendment devices and allows marketing, subject to general controls.
- Indications for Use: Reiterates imaging diffusive mobility of water, visualizing acute stroke, and claims greater accuracy than conventional MRI in identifying acute stroke within the first 24 hours.
Therefore, based solely on the provided text, the following information cannot be extracted:
- A table of acceptance criteria and the reported device performance: Not present.
- Sample size used for the test set and the data provenance: Not present.
- Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not present.
- Adjudication method for the test set: Not present.
- If a multi-reader multi-case (MRMC) comparative effectiveness study was done, and the effect size: Not present.
- If a standalone study (algorithm only without human-in-the-loop performance) was done: Not present (the device is an imaging sequence, not an algorithm in the modern sense).
- The type of ground truth used: Not present.
- The sample size for the training set: Not present.
- How the ground truth for the training set was established: Not present.
The document is a 510(k) summary from 1997, which typically focuses on demonstrating substantial equivalence to a predicate device rather than extensive clinical study data with specific performance metrics and ground truth establishment, as would be expected for a novel AI/software device today. The claims about "more accurate than conventional MRI pulse sequences in identifying the occurrence of acute stroke" are stated under "Indications for Use" but are not backed by a described study within this specific document.
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510 (k) SUMMARY
JUN 20 1997
K971055
This summary of 510(k) safety and effectiveness information is being submit in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.
| General Information. | |
|---|---|
| Establishment:• Address: | Siemens Medical Systems, Inc.186 Wood Avenue SouthIselin, N.J. 08830 |
| • Registration Number: | 2240869 |
| • Contact Person: | Kathleen M. RutherfordManager, Regulatory Submissions(908) 321-4779 |
| • Date of Summary Preparation: | 3/21/97 |
| Device Name:• Trade Name: | Diffusion Weighted- MR Imaging/MAGNETOM Vision |
| • Classification Name: | Magnetic Resonance DiagnosticDevice, CFR § 892.1000 |
| • Classification: | Class II |
| • Performance Standards: | None established under Section514 of the Food, Drug, andCosmetic Act. |
II. Safety and Effectiveness Information Supporting the Substantial Equivalence Determination.
Device Description:
I.
Diffusion sensitivity has been added to the basic echo-planar pulse sequence by applying a large magnetic field gradient pulse before the 180 degree refocusing rf pulse and an identical gradient pulse after the 180 degree rf pulse.
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SIEMENS
Intended Use
The Siemens Diffusion-Weighted MR Imaging Package has been designed to image the diffusive mobility of water or other proton-containing molecules. One important clinical application is to visualize the apparent loss of mobility by water molecules in brain tissue affected by acute stroke.
Technological Characteristics
The technological characteristics of the system remain the same. New sequences will be added to the imaging platform.
General Safety and Effectiveness Concerns:
The most serious drawback of this diffusion-weighted pulse sequence is a consequence of using the echo-planar technique. Echo-planar imaging is very sensitive to magnetic field inhomogeneities, and images are distorted wherever susceptibility effects cause field inhomogeneities. Additional warnings have been included in the applications guide for the Siemens MAGNETOM.
Substantial Equivalence:
The new Diffusion Weighted MRI Sequences are substantially equivalent to commercially available Echo Planar Sequences.
Kathleen Rutherford
Signature
3/21/97
Date
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Image /page/2/Picture/2 description: The image shows a circular logo with the words "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" written around the top half of the circle. Inside the circle is a stylized image of an eagle or bird-like figure. The image is black and white and appears to be a scan or photocopy.
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
JUN 20 1997
Kathleen Rutherford Manager, Regulatory Submissions Siemens Medical Systems, Inc. 186 Wood Avenue South Iselin, NJ 08830
Re: K971055 Diffusion Weighted Imaging (DWI) for MAGNETOM Vision Dated: March 21, 1997 Received: March 24, 1997 Regulatory class: II 21 CFR 892.1000/Procode: 90 LNH
Dear Ms. Rutherford:
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 enaument date of the Modical Device Amendatents, 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 mistoration.
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 Good Manufacturing Practice for Medical Devices: General (GMP) regulation (21 CFR Part 820) and that, through periodic GMP inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulatory action. In addition, FDA may publish further announcements concerning your device in the Edecal Register. Please note: this response to your premarket notification 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 predication 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 vites diagnostic devices), please contact the Office of Compliance at (301) 594-4591 for Radiology devices, or 594-4613 for Ear, Nose and Throat devices. Additionally, for questions on the promotion 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,
William Yu, Ph.D.
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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Ka 11055 510(k) Number (if known) _
Device Name: Diffusion MR Imaging
Indications for Use:
The Siemens Diffusion-Weighted MR Imaging Package has been designed to image the diffusive mobility of water or other proton-containing molecules. One important clinical application is to visualize the apparent loss of mobility by water molecules in brain tissue affected by acute stroke. Areas of decreased diffusion, as is observed in acute cerebral infarcts, appear as areas of higher image intensity.
Diffusion weighted MR pulse sequences are more accurate than conventional MRI pulse scquences in identifying the occurrence of acute stroke during the first 24 hours after onset of symptoms.
(please do not write below this line- continue on another page if needed)
Concurrence of CDRH, Office of Device Evaluation
Prescription Use
OR
Over-The-Counter Use_
William Yi
(Division Sign-Off)
Division of Reproductive, Abdominal, ENT, and Radiological Devices 510(k) Number_
§ 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.