(75 days)
Vantage Galan 3T systems are indicated for use as a diagnostic imaging modality that produces crosssectional transaxial, coronal, sagittal, and oblique images that display anatomic structures of the head or body. Additionally, this system is capable of non-contrast enhanced imaging, such as MRA.
MRI (magnetic resonance imaging) images correspond to the spatial distribution of protons (hydrogen nuclei) that exhibit nuclear magnetic resonance (NMR). The NMR properties of body tissues and fluids are:
·Proton density (PD) (also called hydrogen density)
·Spin-lattice relaxation time (T1)
·Spin-spin relaxation time (T2)
·Flow dynamics
·Chemical Shift
Depending on the region of interest, contrast agents may be used. When interpreted by a trained physician, these images yield information that can be useful in diagnosis.
The Vantage Galan (Model MRT-3020) is a 3 Tesla Magnetic Resonance Imaging (MRI) System, previously cleared under K241496. This system is based upon the technology and materials of previously marketed Canon Medical Systems and is intended to acquire and display crosssectional transaxial, coronal, sagittal, and oblique images of anatomic structures of the head or body.
This document describes a 510(k) premarket notification for the Vantage Galan 3T, MRT-3020, V10.0 with AiCE Reconstruction Processing Unit for MR. This submission concerns a modification to an already cleared device, primarily involving the addition of a standard gradient system and the extension of the Precise IQ Engine (PIQE) to new scan families, weightings, and anatomical areas.
Here's a breakdown of the requested information based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly present a table of quantitative acceptance criteria for PIQE performance. Instead, it describes acceptance in qualitative terms based on expert review.
| Metric/Category | Acceptance Criteria (Implicit) | Reported Device Performance (PIQE) |
|---|---|---|
| Image Quality Metrics (Bench Testing) | Improvement in sharpness, mitigation of ringing, maintenance/improvement of SNR and contrast compared to standard techniques. | Generates images with sharper edges, mitigates smoothing and ringing effects, maintains similar or better contrast and SNR compared to zero-padding interpolation and typical clinical filters. |
| Clinical Image Review (Likert Scale) | Scored "at or above, clinically acceptable" on average. Strong agreement at "good" and "very good" level for all IQ metrics. | All reconstructions scored on average at, or above, clinically acceptable. Exhibited strong agreement at the "good" and "very good" level for all IQ metrics (ringing, sharpness, SNR, overall IQ, feature conspicuity). |
| Functionality | Generate higher spatial in-plane resolution from lower resolution images (up to 9x factor). Reduce ringing artifacts, denoise, and increase sharpness. Accelerate scanning by reducing acquisition matrix while maintaining clinical matrix size and image quality. Obtain benefits on regular clinical protocols without requiring acquisition parameter adjustment. | PIQE achieves these functionalities as confirmed by expert review and technical description. |
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Size: 106 unique subjects.
- Data Provenance: Two sites in the USA and one in Japan. This data is described as "separate from the training data sets." The document states that the multinational study population is expected to be representative of the intended US population for PIQE, as PIQE is an image post-processing algorithm not disease-specific or dependent on acquisition parameters that might be affected by population variation. Comparisons were internal (each subject as its own control).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
- Number of Experts: 14 USA board-certified radiologists and cardiologists (3 reviewers per anatomy).
- Qualifications: "USA board-certified radiologists and cardiologists." Specific experience levels (e.g., years of experience) are not provided.
4. Adjudication Method for the Test Set
The document describes a scoring process by multiple reviewers but does not specify a formal adjudication method (e.g., 2+1, 3+1). It states: "scored by 3 reviewers per anatomy in various clinically-relevant categories... Reviewer scoring data was analyzed for reviewer agreement and differences between reconstruction techniques using Gwet's Agreement Coefficient and Generalized Estimating Equations, respectively." This suggests that the scores from the three reviewers were aggregated and analyzed statistically, rather than undergoing a consensus or tie-breaking adjudication process for each individual case.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, What was the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance
- MRMC Study: Yes, a multi-site, randomized, blinded clinical image review study was conducted.
- Effect Size (AI-assisted vs. without AI assistance): This was not an AI-assisted reader study. The study compared images reconstructed with the conventional method (matrix expansion with Fine Reconstruction and typical clinical filter) against images reconstructed with PIQE. The purpose was to evaluate the image quality produced by PIQE, not to assess reader performance with or without AI assistance. Therefore, no effect size on human reader improvement with AI assistance is reported. The study aimed to demonstrate that PIQE-reconstructed images are clinically acceptable and offer benefits like sharpness and ringing reduction.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, a standalone performance evaluation of the PIQE algorithm was conducted through "bench testing." This involved evaluating metrics like Edge Slope Width, Ringing Variable Mean, Signal-to-Noise ratio, and Contrast Change Ratio on typical clinical images from various anatomical regions. This bench testing demonstrated that PIQE "generates images with sharper edges while mitigating the smoothing and ringing effects and maintaining similar or better contrast and SNR."
7. The Type of Ground Truth Used
- For Bench Testing: The "ground truth" implicitly referred to established quantitative image quality metrics (Edge Slope Width, Ringing Variable Mean, Signal-to-Noise ratio, and Contrast Change Ratio) and comparisons against conventional reconstruction methods.
- For Clinical Image Review Study: The "ground truth" was established by expert consensus/evaluation, where 14 board-certified radiologists and cardiologists scored images on various clinically-relevant categories (ringing, sharpness, SNR, overall IQ, and feature conspicuity) using a modified 5-point Likert scale.
8. The Sample Size for the Training Set
The document explicitly states that the "106 unique subjects... from two sites in USA and one in Japan... were scanned... to provide the test data sets (separate from the training data sets)." The sample size for the training set is not provided in the document.
9. How the Ground Truth for the Training Set Was Established
The document does not provide information on how the ground truth for the training set was established, as details about the training set itself are omitted.
§ 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.