(28 days)
The SIGNA Artist system is a whole body magnetic resonance scanner designed to support high signalto-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, heart, 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 the SIGNA Artist system reflect the spatial distribution or molecular environment of nuclei exhibiting magnetic resonance. These images and/or spectra when interpreted by a trained that may assist in diagnosis.
The SIGNA Artist system is a whole body magnetic resonance scanner designed to support high resolution, high signal-to-noise ratio, and short scan times. The system features a superconducting magnet. The data acquisition system accommodates up to 128 independent receive channels in various increments and multiple independent coil elements per channel during a single acquisition series. The system uses a combination of time varying magnetic 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 double oblique planes, using various pulse sequences and reconstruction algorithms.
This 510(k) submission is for the SIGNA Artist 1.5T MR system, and has been triggered by the addition of the AIR Recon DL software feature.
The AIR Recon DL feature has been previously cleared for use on the SIGNA Premier 3T system through K193282, which is used as a reference device for this submission.
Here's a breakdown of the acceptance criteria and the study that proves the device meets them, based on the provided text:
Acceptance Criteria and Device Performance for GE Healthcare SIGNA Artist with AIR Recon DL
The provided document describes the 510(k) submission for the GE Healthcare SIGNA Artist system with the added AIR Recon DL software feature. The study focuses on evaluating the impact of this new feature on image quality.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Specific Criteria | Reported Device Performance |
|---|---|---|
| Image Quality | SNR (Signal-to-Noise Ratio) Improvement: Improved SNR with AIR Recon DL. | Nonclinical and clinical testing demonstrated that AIR Recon DL improves SNR. Additionally,AIR Recon DL was able to maintain image SNR for images acquired with a reduced scan time. |
| Sharpness Improvement: Improved image sharpness with AIR Recon DL. | Nonclinical and clinical testing demonstrated that AIR Recon DL improves image sharpness. Additionally,AIR Recon DL did not sacrifice sharpness for images acquired with a reduced scan time. | |
| Low Contrast Detectability: Maintenance of low contrast detectability with AIR Recon DL. | Nonclinical testing confirmed that AIR Recon DL maintains low contrast detectability. | |
| Noise Spectral Content Impact: Minimal impacts to noise spectral content with AIR Recon DL. | Nonclinical testing confirmed that AIR Recon DL has minimal impacts to noise spectral content. | |
| Average Signal Intensity Bias: No significant bias introduced that might impact quantitative measurements based on signal intensity. | Analysis was performed to confirm that the feature does not introduce significant bias that might impact quantitative measurements based on signal intensity. | |
| Motion Artifact Impact: Minimal impacts to the appearance of motion artifacts. | Nonclinical testing confirmed that AIR Recon DL has minimal impacts to the appearance of motion artifacts. | |
| Clinical Acceptability | Equivalent or Better Image Quality: Images produced with AIR Recon DL should have equivalent or better image quality compared to images without the feature as rated by radiologists. | Radiologists were asked to rate images and comment on quality; the study showed that the AIR Recon DL feature provides images with equivalent or better image quality. |
| Maintained Lesion Conspicuity: Lesion conspicuity should be maintained with AIR Recon DL. | The study showed that lesion conspicuity is maintained. | |
| Radiologist Preference: Radiologists should prefer AIR Recon DL images for clinical use. | The study showed that the radiologists preferred the AIR Recon DL images for clinical use. | |
| Scan Time | Shorter Scan Times: Ability to enable shorter scan times while maintaining SNR and image sharpness. | Nonclinical and clinical testing demonstrated that AIR Recon DL can enable shorter scan times while maintaining SNR and image sharpness. |
| Safety and Performance | No New Hazards/Adverse Effects: The feature should not introduce any new hazards, adverse effects, or safety and performance concerns significantly different from those associated with MR imaging in general. | The performance testing did not identify any new hazards, adverse effects, or safety and performance concerns that are significantly different from those associated with MR imaging in general. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly state the specific sample size for the test set used in the clinical evaluation. It mentions "sample images from clinically indicated scans."
The data provenance for the clinical evaluation is implied to be retrospective as it involves "sample images from clinically indicated scans" that were then evaluated with and without the AIR Recon DL feature. The country of origin of the data is not specified.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
The document states that "Radiologists were asked to rate the images, and to comment on any notable aspects related to image quality." It does not specify the exact number of experts or their qualifications (e.g., years of experience, subspecialty).
4. Adjudication Method for the Test Set
The adjudication method is not explicitly stated. The text only mentions that "Radiologists were asked to rate the images, and to comment on any notable aspects related to image quality." This suggests an individual review process, but it doesn't detail how discrepancies or consensus building was handled if multiple radiologists reviewed the same case. It doesn't mention methods like 2+1, 3+1, or majority vote.
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
A multi-reader multi-case (MRMC) comparative effectiveness study was not explicitly stated as the primary methodology. The clinical evaluation described involves radiologists rating images "both with and without the AIR Recon DL feature" and stating their preference. While this provides comparative feedback, it does not quantify human reader improvement in terms of diagnostic accuracy or a specific effect size. The study concludes that radiologists "preferred the AIR Recon DL images for clinical use" and that lesion conspicuity was maintained, indicating a subjective improvement, but not a measurable effect size of diagnostic performance.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done
Yes, a standalone performance evaluation was done as part of the "Nonclinical Tests." These tests were designed to evaluate the AIR Recon DL feature "and its impact on image quality, including SNR, sharpness, low contrast detectability, and noise spectral content. Analysis was performed to confirm that the feature does not introduce significant bias that might impact quantitative measurements based on signal intensity. The influence of motion during image acquisition on the performance of AIR Recon DL was also evaluated." These are objective, quantitative measurements of the algorithm's output without human interpretation being the primary endpoint.
7. The Type of Ground Truth Used
For the nonclinical tests, the ground truth appears to be based on objective image quality metrics, physical phantoms, and simulated conditions. For instance, evaluating SNR, sharpness, noise spectral content, a lack of signal intensity bias, and motion artifact influence against established benchmarks or predefined ideal conditions.
For the clinical tests, the ground truth for "equivalent or better image quality" and "maintained lesion conspicuity" was established by expert consensus/opinion from radiologists.
8. The Sample Size for the Training Set
The document does not specify the sample size for the training set used for the AIR Recon DL algorithm. It only mentions that the AIR Recon DL feature "has been previously cleared for use on the SIGNA Premier 3T system through K193282, which is used as a reference device for this submission." This implies the training was done prior to this specific submission for the SIGNA Artist.
9. How the Ground Truth for the Training Set Was Established
The document does not provide details on how the ground truth for the training set was established for the AIR Recon DL algorithm. While it mentions the algorithm was previously cleared for another device, it does not elaborate on the specific data used for its initial training and ground truth annotation.
§ 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.