(66 days)
Magnetic Resonance Imaging of small extremity joints.
The modification is the addition of a flexible coil to image the elbow, hand, ankle, foot, and other small extremity joints. The coil is similar in design to the predicate device, a legally marketed Flexible Coil (K944331). The only significant modification is with respect to the frequency for the 2 Tesla model because the predicate device was designed only for 0.5T, 1.0T and 1.5T systems.
Here's an analysis of the provided information, describing the acceptance criteria and the study that proves the device meets them:
Acceptance Criteria and Device Performance
The provided document describes a 510(k) submission for a modification to an existing device, a Flex Coil for MRI systems. As such, the "acceptance criteria" are primarily based on demonstrating substantial equivalence to predicate devices in terms of safety and effectiveness, rather than meeting specific quantifiable performance metrics for a novel diagnostic algorithm.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Specific Criterion | Reported Device Performance and Evidence (Flex Coil) |
|---|---|---|
| Safety | No adverse impact on MRI safety parameters (SAR, dB/dt, Bo, acoustic noise). | * MRI safety parameters (SAR, dB/dt, Bo, acoustic noise) do not apply to passive coils. |
| Avoidance of electric shock hazards. | * Enclosures designed to comply with clause 16 of IEC-601-1 safety standard. | |
| Avoidance of injury from rough surfaces, sharp corners, and edges. | * Design according to clause 23 of the IEC-601-1 standard. | |
| Coil enclosures and protective covers meet flammability standards. | * Flame rated better than CPAI-84. | |
| No software modifications. | * No software modifications have been made. | |
| Patient contacting materials are identical to predicate device. | * All patient contacting materials are identical to those used in the predicate Flexible Coil (K944331). | |
| No impact on site planning, installation, service manuals, or safety labeling. | * Current modifications do not affect site planning, installation, service manuals, and do not require new safety labeling. | |
| Effectiveness | Acceptable uniformity. | * The Elscint 0.5T and 2T Flex Coils have acceptable uniformity. (Specific quantifiable metrics for "acceptable" are not provided in this summary.) |
| Higher Signal-to-Noise Ratio (SNR) compared to the predicate Shoulder Coil. | * The Elscint 0.5T and 2T Flex Coils have higher SNR than the Shoulder Coil. (Specific quantitative SNR values or improvement percentages are not provided.) | |
| Improved image quality compared to the predicate Shoulder Coil. | * The images produced by the Flex Coils are better than those produced using the Shoulder Coils on the same systems. (This is a subjective assessment of image quality, without further detail on how "better" was defined or measured.) | |
| Substantial Equivalence | The device is substantially equivalent to predicate devices in terms of safety and effectiveness, including the frequency specified for the 2 Tesla model. | * The device is "substantially equivalent to the predicate devices in terms of safety and effectiveness," with the specific note that the modification mainly involves the frequency for the 2 Tesla model since the predicate was for 0.5T, 1.0T, and 1.5T. Implicitly, by accepting the 510(k), the FDA agreed with this assessment. |
Study Details Proving Acceptance Criteria
The provided document is a summary of a 510(k) premarket notification. It does not describe a formal scientific "study" in the way one might evaluate a new diagnostic algorithm. Instead, it demonstrates substantial equivalence through a comparison to existing, legally marketed predicate devices and by outlining compliance with relevant safety standards.
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly state a "test set sample size" or "data provenance" in terms of patient data. The evaluation appears to be based on:
- Engineering Analysis and Compliance: Demonstrating adherence to IEC safety standards.
- Bench Testing/Performance Evaluation: Stating "acceptable uniformity," "higher SNR," and "better images" compared to the Shoulder Coil. This would imply some form of imaging or phantom tests, but no specifics are given regarding the number of images, phantoms, or human subjects used.
- Comparison to Predicate: The primary "test" is a comparison of the modified device's characteristics against those of the predicate devices.
Given the context of a 510(k) for a coil modification, it's highly likely that this involved a limited number of phantom images and possibly images from volunteer subjects, but no large-scale patient study aiming for statistical significance is described.
- Data Provenance: Not specified, but likely internal testing by Elscint. Retrospective or prospective nature is not indicated for any observed performance.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
- Not Applicable in the traditional sense. For a device like a new MRI coil, "ground truth" isn't typically established by expert consensus on clinical diagnoses within a test set. Instead, performance metrics like uniformity and SNR are objectively measured. Subjective "better images" assessment might involve internal engineers or physicists, but the number and qualifications are not specified.
4. Adjudication Method for the Test Set
- Not Applicable. As there's no defined "test set" requiring clinical diagnosis or interpretation, no adjudication method would have been used. Performance metrics like SNR and uniformity are objectively measured characteristics of the coil's physical properties.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done
- No. An MRMC study was not done. The effectiveness claims ("higher SNR," "better images") are implicitly based on direct comparison to the predicate shoulder coil, likely through technical specifications or qualitative review, not a formal multi-reader study.
6. If a Standalone Study (i.e., algorithm only without human-in-the-loop performance) was Done
- Yes (Implicitly). The evaluation of the coil's physical performance characteristics (uniformity, SNR) is a standalone assessment of the device hardware. The statement "The Elscint 0.5T and 2T Flex Coils have acceptable uniformity and higher SNR than the Shoulder Coil" indicates a standalone assessment of the coil's imaging capabilities without human interpretation influencing the raw metrics. The claim of "better images" is a subjective standalone assessment.
7. The Type of Ground Truth Used
- For safety: Compliance with international safety standards (IEC-601-1) and material specifications (CPAI-84).
- For effectiveness: Objective physical measurements (e.g., uniformity, SNR, though specific metrics are not provided) and qualitative comparative assessment ("better images") against a predicate device.
8. The Sample Size for the Training Set
- Not Applicable. The device is a hardware component (an MRI coil), not an AI algorithm that requires a "training set" of data.
9. How the Ground Truth for the Training Set Was Established
- Not Applicable. As there is no training set, there is no ground truth established for one.
§ 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.