(122 days)
The SIGNA 7.0T System is a whole-body magnetic resonance scanner designed to support high signal-tonoise 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 head and extremities.
The images produced by the SIGNA 7.0T System 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.
The device is intended for patients > 20 kg / 44 lbs.
SIGNA 7.0T is a high performance magnetic resonance imaging system designed to support high resolution imaging at 7.0T in particular anatomical regions determined by the available RF coils. The system includes a 7.0T superconducting magnet and an ultra-high performance gradient coil with a 60 cm patient bore, supporting scanning in axial, coronal, sagittal, oblique, and double oblique planes using a variety of pulse sequences, imaging techniques, acceleration methods, and reconstruction algorithms.
Here's an analysis of the acceptance criteria and the study conducted for the GE SIGNA 7.0T Magnetic Resonance Diagnostic Device, based on the provided text:
Important Note: The provided text is a 510(k) summary, which focuses on demonstrating substantial equivalence to a predicate device rather than presenting a detailed clinical study for novel claims or specific performance metrics against pre-defined acceptance criteria for a new AI-powered diagnostic. Therefore, some of the requested information (like specific quantitative acceptance criteria for image quality, expert qualifications beyond "radiologist," or a detailed MRMC study effect size) is not explicitly present in the given document. The analysis below extracts what is available and makes inferences where appropriate based on the nature of a 510(k) submission for an imaging device.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Image Diagnostic Quality | Equivalent to predicate 3.0T system for head and extremities. Assessed for diagnostic quality, usability, personal preferences, and general commentary. |
| PNS (Peripheral Nerve Stimulation) Limits | Established for the SIGNA 7.0T system. |
| Safety and Effectiveness | At least as safe and effective as the legally marketed predicate device. No new hazards, adverse effects, or safety/performance concerns identified that are significantly different from general MR imaging. |
| Compliance with Standards | Complies with ANSI/AAMI ES60601-1, AAMI/ANSI/IEC 60601-1-2, IEC 60601-2-33, AAMI/ANSI/IEC 62304, AAMI/ANSI/ISO 10993-1, applicable NEMA MS standards for MRI, and NEMA PS3 standards for DICOM. |
Explanation of Implied Acceptance Criteria: The document describes the study's purpose as evaluating image diagnostic quality and usability against the predicate device. For a 510(k), the acceptance criterion for image quality is generally that the new device's images are diagnostically equivalent or non-inferior to the predicate device's images for the stated indications for use. "Acceptance" here means that the FDA agreed that the device met the requirements for substantial equivalence.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Image Quality Study (Test Set):
- Subjects: Not explicitly stated, but images were acquired from "normal subjects and subjects with self-reported common neuropathology" for brain scans, and individuals over a "broad age range representative of a range of knee health" for knee images. The specific number of subjects/cases is not provided.
- Image Series: Included brain MR scans and knee images.
- Sample Size for PNS Limits Study: Not explicitly stated, but involved "adult human volunteers without reported pathology."
- Data Provenance: Not explicitly stated, but given it's a US submission and refers to "U.S. board-certified radiologists," it is highly probable the data was collected in the United States. The study was prospective in the sense that the images were acquired specifically for this evaluation using both the proposed and predicate devices.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- Number of Experts: 4
- Qualifications: "U.S. board-certified radiologists." No specific years of experience are provided, but board certification implies a certain level of expertise.
4. Adjudication Method for the Test Set
The document states, "The study involved 4 U.S. board-certified radiologists evaluating proposed device's image diagnostic quality and usability, personal preferences, and general commentary using radiology terms against same subject images scanned on the predicate device."
This description suggests that the radiologists independently evaluated images from both devices. It does not explicitly describe a formal adjudication method (like 2+1 or 3+1 consensus). It's more likely that their individual assessments were collected and analyzed, potentially looking for consistency or a majority opinion on diagnostic quality comparison. Without further detail, we cannot definitively state a formal adjudication method was used, beyond individual evaluations.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance
- MRMC Study: Yes, a reader evaluation study was performed. It involved multiple readers (4 radiologists) evaluating multiple cases (brain and knee images).
- Effect Size (AI Assistance): This device is an MR scanner, not an AI diagnostic algorithm. Therefore, the study did not involve human readers improving with AI assistance. The comparison was between the image quality from the new 7.0T MR scanner versus the predicate 3.0T MR scanner.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
- No, this question is not applicable. The SIGNA 7.0T is an imaging device, not an AI algorithm. No standalone algorithm performance was evaluated.
7. The Type of Ground Truth Used
For the image quality evaluation, the "ground truth" was established by expert consensus/opinion (or individual expert assessments, given the lack of explicit adjudication) regarding the diagnostic quality and usability of the images. They compared images from the proposed 7.0T system against the predicate 3.0T system. There is no mention of pathology, clinical outcomes, or other objective ground truth for the diagnostic findings themselves, but rather whether the images produced were suitable for diagnosis.
For the PNS limits, the ground truth was direct determination in human volunteers.
8. The Sample Size for the Training Set
- This device is an MR scanner, not an AI algorithm that requires a "training set" in the machine learning sense. Therefore, this question is not applicable. The device's "training" would refer to its engineering development and calibration, which is a different concept.
9. How the Ground Truth for the Training Set Was Established
- This question is not applicable, as there is no "training set" in the context of an AI algorithm.
§ 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.