(91 days)
The OASIS 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, oblique, and curved cross-sectional images that display the internal structure of the head, body, or extremities. 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-latice 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 OASIS is a Magnetic Resonance Imaging System that utilizes a 1.2 Tesla superconducting maqnet in a qantry design.
The provided text describes a 510(k) premarket notification for the Hitachi OASIS MRI System, focusing on demonstrating substantial equivalence to a predicate device (OASIS MRI System K192851). The document primarily outlines changes made to the device and provides a rationale for why these changes do not affect safety or effectiveness, rather than presenting a detailed study with specific acceptance criteria and performance metrics in the typical sense of a diagnostic AI device.
Therefore, the requested information, particularly regarding specific numerical acceptance criteria, performance metrics, sample sizes for test/training sets, expert qualifications, and adjudication methods, is not explicitly available in the provided text as it would be for an AI/CADe device. The submission focuses on demonstrating that modifications to an existing MRI system (hardware, coils, software updates) do not negatively impact its performance compared to the predicate.
Here's an analysis based on the information available in the document, and what is missing:
1. Table of Acceptance Criteria and Reported Device Performance
This information is not explicitly stated in a quantifiable table as requested. The document asserts "substantial equivalence" as the primary "acceptance criterion" indirectly. The performance evaluation is focused on demonstrating that new features and changes "perform as intended for diagnostic use" and that the device modifications "do not raise different questions of safety and effectiveness."
| Acceptance Criteria (Implied) | Reported Device Performance (Implied) |
|---|---|
| Device performs as intended for diagnostic use. | "Performance bench testing was conducted on the applicable new features. Test data confirmed that each new feature perform as intended for diagnostic use." |
| Changes do not raise different questions of safety. | Hardware: "For safety, gradient system and RF system is controlled according to same regulation as OASIS (K192851). So, safety and effectively of the device are same as OASIS (K192851)." |
| Coils: "During transmitter coil operation, RF Coils are de-resonated by same scheme as OASIS (K192851)." | |
| Functionality: "For safety, pulse sequences are controlled according to same safety limits as OASIS (K192851). So safety and effectivity of the device are equivalent to the OASIS (192851)." | |
| System meets NEMA and IEC standards for MRI systems (e.g., NEMA MS-1, MS-3, MS-8; IEC 60601-1, 60601-1-2, 60601-2-33, 62304). | |
| Changes do not raise different questions of effectiveness. | Hardware: "Modified specification doesn't constitute a new intended use. There are no significant changes in technological characteristics... effectiveness of the device are same as OASIS (K192851)." |
| Coils: "Additional or modified coils did not constitute a new intended use. There are no significant changes in technological characteristics." | |
| Functionality: "Modified functions do not constitute a new intended use. There are no significant changes in technological characteristics... effectivity of the device are equivalent to the OASIS (192851)." | |
| "Clinical image examples are provided for each applicable new feature... and that we judged to be sufficient to evaluate clinical usability." | |
| Substantial Equivalence to Predicate Device (K192851). | "It is the opinion of Hitachi, the OASIS MRI system is substantially equivalent with respect to hardware, base elements of the software, safety, effectiveness, and functionality to the OASIS MRI System (K192851)." |
2. Sample size used for the test set and the data provenance
The document mentions "Clinical image examples are provided for each applicable new feature." It describes these examples as "sufficient to evaluate clinical usability."
- Sample Size: Not specified. It's implied to be a collection of "examples" rather than a statistically powered test set for quantitative performance.
- Data Provenance: Not specified (e.g., country of origin, retrospective/prospective). It likely refers to internal testing data.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Number of Experts: Not specified. The phrase "we judged to be sufficient to evaluate clinical usability" suggests internal evaluation.
- Qualifications of Experts: Not specified.
4. Adjudication method for the test set
- Adjudication Method: Not specified.
5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, and effect size of human readers improvement with AI vs without AI assistance
- MRMC Study: No, this is not an AI/CADe device. The submission concerns an MRI system itself and its modifications, not an AI-powered diagnostic aid. Therefore, no MRMC study comparing human readers with and without AI assistance was performed or needed.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Standalone Performance: No, this is not an AI/CADe device. The assessment is on the MRI system's ability to produce diagnostic images. The "standalone" performance here refers to the system meeting technical standards (NEMA, IEC) and producing images deemed clinically usable.
7. The type of ground truth used
The "ground truth" implicitly used for the clinical image examples is expert judgment of clinical usability of the images. This is not pathology, outcomes data, or a pre-established consensus for specific findings, but rather an assessment that the images produced by the modified system remain suitable for diagnosis by a trained physician.
8. The sample size for the training set
- Training Set Sample Size: Not applicable. This device is an MRI system, not a machine learning algorithm that requires a "training set" in the context of AI.
9. How the ground truth for the training set was established
- Training Set Ground Truth Establishment: Not applicable, as it's not an AI/ML device.
§ 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.