(205 days)
The SIGNA Prime is a whole body magnetic resonance scanner designed to support high resolution, high signal-to-noise ratio, and short scan times. It is indicated for use as a diagnostic imaging device to produce axial, sagittal, coronal, and oblique images, spectroscopic images, parametric maps, and/or spectra, dynamic images of the structures and/or functions of the entire body, including, but not limited to, head, neck, TMI, spine, abdomen, pelvis, joints, prostate, blood vessels, and musculoskeletal regions of the body.
Depending on the region of interest being imaged, contrast agents may be used. The images produced by SIGNA Prime reflect the spatial distribution or molecular environment of nuclei exhibiting magnetic resonance.
These images and/or spectra when interpreted by a trained physician yield information that may assist in diagnosis.
SIGNA™ Prime is a whole body magnetic resonance scanner designed to support high resolution, high signal to-noise ratio, and short scan times. The systems use a combination of time-varying magnet fields (Gradients) and RF transmissions to obtain information regarding the density and position of elements exhibiting magnetic resonance. The system can image in the sagittal, coronal, axial, oblique, and oblique planes, using various pulse sequences, imaging techniques and reconstruction algorithms. The system features a 1.5T superconducting magnet with 60cm bore size. The system is designed to conform to NEMA DICOM standards (Digital Imaging and Communications in Medicine).
The provided text is a 510(k) summary for the GE Healthcare SIGNA Prime magnetic resonance diagnostic device. The summary states that the device did not require clinical studies to support substantial equivalence and instead relied on non-clinical tests and sample clinical images to demonstrate acceptable diagnostic image performance.
Therefore, the study details requested cannot be fully provided as a formal comparative effectiveness study or standalone performance study as typically understood for AI/CADe devices was not conducted with predefined acceptance criteria for diagnostic metrics.
Here's a breakdown of the available information:
1. Table of Acceptance Criteria and Reported Device Performance:
No specific numerical acceptance criteria for diagnostic performance (e.g., sensitivity, specificity, AUC) are provided in the document. The general acceptance criterion was that the image quality of the SIGNA Prime is "substantially equivalent" to that of the predicate device (SIGNA Creator, K143251).
| Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|
| Image quality substantially equivalent to predicate device. | Sample clinical images demonstrate acceptable diagnostic image performance and substantial equivalence to the predicate device. |
| Compliance with voluntary standards (e.g., IEC, NEMA, ISO). | The device complies with listed voluntary standards. |
| Passed risk management testing. | Risk management testing was successfully conducted. |
2. Sample size used for the test set and the data provenance:
- Sample Size: The document mentions "Sample clinical images have been included in this submission" but does not specify the number of images or cases used as a "test set."
- Data Provenance: Not specified. It's unclear if these were retrospective or prospective, or the country of origin.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- The document states that "These images and/or spectra when interpreted by a trained physician yield information that may assist in diagnosis." However, it does not specify the number or qualifications of experts who interpreted the "sample clinical images" for the purpose of demonstrating substantial equivalence. The mechanism for establishing ground truth for these sample images is not detailed.
4. Adjudication method for the test set:
- Not specified. Given that a formal clinical study with a detailed ground truth process is not described, an adjudication method for a test set is not mentioned.
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:
- No. The document explicitly states: "The subject of this premarket submission, the SIGNA™ Prime, did not require clinical studies to support substantial equivalence." Therefore, an MRMC comparative effectiveness study involving human readers with and without AI assistance was not performed or reported.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- The SIGNA Prime is a magnetic resonance scanner, not an AI algorithm or CADe device. Therefore, the concept of "standalone (algorithm only without human-in-the-loop performance)" is not applicable in this context. The device itself produces images for human interpretation.
7. The type of ground truth used:
- For the "sample clinical images" used to demonstrate acceptable diagnostic image performance, the ground truth is implicitly expert interpretation by a "trained physician" as stated in the Indications for Use. However, the exact methodology for establishing this ground truth for the purpose of the submission is not detailed (e.g., expert consensus vs. pathology vs. outcomes data).
8. The sample size for the training set:
- Not applicable. The SIGNA Prime is a hardware device (MRI scanner) with associated software, not an AI/ML algorithm that is "trained" on a dataset in the typical sense. While the software platform and reconstruction algorithms were likely developed and refined, the document does not describe a "training set" in the context of an AI algorithm evaluation.
9. How the ground truth for the training set was established:
- Not applicable. (See point 8).
Summary of the Study:
The K211980 submission for the SIGNA Prime focused on demonstrating substantial equivalence to a predicate device (SIGNA Creator, K143251). This was primarily achieved through:
- Non-clinical tests: Compliance with various electrical, safety, software, and biocompatibility standards (e.g., ANSI/AAMI ES60601-1, IEC 60601-1-2, IEC 60601-2-33, IEC 62304, IEC 60601-1-6, IEC 62366-1, ISO 10993-1, NEMA MS, NEMA PS3 DICOM).
- Risk management activities: Including risk analysis, design reviews, and various levels of testing (unit, integration, performance, simulated use).
- Sample clinical images: These images were provided to demonstrate acceptable diagnostic performance and visual equivalence to the predicate device. However, the specific methodology for selecting, evaluating, or establishing ground truth for these sample images is not detailed, nor are any quantitative metrics provided for their performance.
The submission explicitly states that clinical studies were not required to support substantial equivalence. Therefore, the detailed information typically sought for the evaluation of AI/CADe devices (such as sample sizes for test/training, expert qualifications, adjudication methods, or MRMC study results) is not present in this document.
§ 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.