(23 days)
The AURORA MRI system is an imaging device, and is intended to provide the physician with physiological and clinical information obtained non-invasively and without the use of ionizing radiation. The MR system produces transverse, coronal, sagittal, and oblique cross-sectional images that display the internal structure of the extremities (breast tissue, axilla, and chest wall local to the breast). The images produced by the MR system reflect the spatial distribution of protons (hydrogen nuclei) exhibiting magnetic resonance. The NMR properties that determine the image appearance are proton density spin-lattice relaxation time (T1), spin-spin relaxation time (T2), and flow. When interpreted by a trained physician, these images provide information that can be useful in diagnosis determination.
The AURORA is a dedicated breast MRI system intended to be used as an adjunct to conventional breast screening methods.
The modified AURORA is identical to the AURORA breast imaging system cleared by FDA through K012154 except that the magnet is ramped to 1.5 T and the RF system and spectrometer have been changed to operate at the higher frequencies required for 1.5 T operation.
Here's an analysis of the provided text regarding the acceptance criteria and study for the AURORA Magnetic Resonance Diagnostic Device:
Critical Observation: The provided document is a 510(k) summary for a modification to an existing medical device (AURORA MRI system, K012154). The modification is specifically an upgrade from a 0.5 T magnet to a 1.5 T magnet and associated RF system and spectrometer changes. This significantly impacts the type of "study" described, as it's not a full de novo clearance for a new device, but rather a demonstration of substantial equivalence.
Based on the provided text, the "study" conducted for this 510(k) clearance is primarily focused on technical performance validation rather than clinical efficacy or diagnostic accuracy with human interpretation.
Acceptance Criteria and Reported Device Performance
The "acceptance criteria" for this specific 510(k) are implicitly tied to demonstrating that the 1.5 T AURORA system performs as expected for an MRI device and is substantially equivalent to the predicate device, despite the magnet strength increase. The testing focused on technical specifications rather than diagnostic performance.
| Acceptance Criterion (Implicit) | Reported Device Performance and Methodology |
|---|---|
| Maintain acceptable imaging functionality post magnet upgrade | "Testing was performed to validate the performance of the AURORA operating at 1.5 T." |
The document explicitly states:
- Acoustic Noise Measurement: Measured to ensure it meets safety and performance standards.
- Specific Absorption Rate (SAR) Measurement: Measured to ensure patient safety regarding RF energy absorption.
- Slice Thickness Measurement: Measured to confirm imaging precision.
- Signal-to-Noise Ratio (SNR) Measurement: Measured to assess image quality and clarity.
- Image Uniformity Measurement: Measured to ensure consistent image quality across the scanned area.
Methodology: According to NEMA (National Electrical Manufacturers Association) standards, indicating recognized industry testing protocols for MR systems. |
| Substantial Equivalence to Predicate Device (K012154) | The entire submission is based on the claim of substantial equivalence. The argument is that the intended use, design, and technological/operational characteristics are similar, with the key difference being the magnet strength and corresponding RF/spectrometer changes. |
Study Details
Given the nature of the 510(k) (upgrade to an existing system, not a new clinical diagnostic device), many of the requested details about clinical studies, expert-read data, and ground truth are not present or applicable in this specific document. The "study" described is a technical validation of system performance.
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Sample Size Used for the Test Set and Data Provenance:
- Test Set Sample Size: Not applicable. The testing described focuses on device parameters (acoustic noise, SAR, etc.) using standards and phantoms, not a sample of patient data for diagnostic evaluation.
- Data Provenance: Not applicable in the context of clinical data. The testing was conducted according to NEMA standards, which implies controlled laboratory or testing environments using phantoms or specialized measurement equipment. No country of origin for clinical data is mentioned as no clinical data study of diagnostic accuracy is discussed. The testing is likely internal engineering validation.
- Retrospective/Prospective: Not applicable to the described technical testing.
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Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:
- Not applicable. Ground truth for diagnostic performance is not established because the "test set" is not a set of clinical cases requiring diagnosis. The "ground truth" for the technical measurements would be the NEMA standard specifications themselves.
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Adjudication Method for the Test Set:
- Not applicable. No expert adjudication of diagnostic findings is mentioned.
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If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done:
- No. No MRMC study is mentioned. The focus is on the technical performance of the MRI hardware, not on reader performance or diagnostic accuracy.
- Effect Size of Human Readers Improve with AI vs. Without AI Assistance: Not applicable, as no AI component or clinical reader study is discussed.
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If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done:
- Yes, in spirit, but not as an "algorithm." The "standalone" performance here refers to the device's technical specifications (SNR, uniformity, etc.) measured independently, without human diagnostic interpretation as part of the evaluation for this 510(k). There is no "algorithm" in the sense of AI being evaluated.
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The Type of Ground Truth Used:
- For the technical performance evaluations (acoustic noise, SAR, slice thickness, SNR, image uniformity), the ground truth is against pre-defined technical specifications and NEMA standards. There is no clinical "ground truth" (e.g., pathology, outcomes data) mentioned in this submission as it's not a clinical performance study.
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Sample Size for the Training Set:
- Not applicable. This device is an MRI scanner, not an AI-powered diagnostic tool. There is no "training set" in the context of machine learning or algorithms. The "training" for the device would involve calibration and quality control procedures, not data for an algorithm.
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How the Ground Truth for the Training Set Was Established:
- Not applicable, as there is no "training set" for an algorithm.
In summary, this 510(k) is for a technical upgrade of an existing MRI device. The "study" described is a technical validation of the physical and imaging performance characteristics of the 1.5 T system against established engineering and NEMA standards, not a clinical study to assess diagnostic accuracy or the performance 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.