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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:

1. A table of acceptance criteria and the reported device performance: Not present.
2. Sample size used for the test set and the data provenance: Not present.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not present.
4. Adjudication method for the test set: Not present.
5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, and the effect size: Not present.
6. 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).
7. The type of ground truth used: Not present.
8. The sample size for the training set: Not present.
9. 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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