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510(k) Data Aggregation
(247 days)
MR-TOUCH OPTION
MR-Touch™, is a software and hardware option intended for use with GE Signa® MR systems. It is indicated for magnetic resonance imaging of the human body.
MR-Touch™ generates transverse sectional information related to the relative stiffness of soft tissue. It consists of hardware as well as acquisition and reconstruction software. The hardware components induce vibrations into the scan subject. The MR-Touch™ acquisition software is an evolutionary improvement to the gradient echo sequence. The sequence synchronizes the induced vibrations to acquire a series of phase-contrast images over time. The phase-contrast imaging technique measures motion or displacement. The displacement from the induced vibrations is detected using the timeseries of phase-contrast images. The displacement information is reconstructed and presented as strain wave and relative stiffness images.
When used with a GE Signa® MR system, MR-Touch™ is capable of producing transverse images of internal body structures such as muscle and liver.
When interpreted by a trained physician, these images may provide information that can be useful in determining a diagnosis.
MR-Touch™ is a combined software and hardware accessory for use with a GE Signa® MR System. It is an evolutionary improvement of the existing phase-contrast imaging feature included with existing GE Signa® MR Systems. The Resoundant hardware component consists of an acoustic wave generator coupled through a length of flexible tubing with a passive transducer to induce small vibrations in the scan subject. The software includes both image acquisition and reconstruction components. The acquisition software is a gradient echo sequence that acquires a series of phase-contrast images over time. It also synchronizes the low frequency and low magnitude induced vibrations generated by Resoundant. The phase-contrast imaging technique measures motion or displacement. During reconstruction, the displacement from the induced vibrations is detected using the timeseries of phase-contrast images. MR-Touch™ then presents the reconstructed displacement information as strain wave and relative stiffness images (referred to as Elastograms).
The GE Healthcare MR-Touch™ Option for GE Signa® MR Systems is an accessory designed to generate transverse sectional information related to the relative stiffness of soft tissue. It comprises hardware for inducing vibrations and software for image acquisition and reconstruction. The primary claim is substantial equivalence to existing MR systems and elastography ultrasound systems.
1. Acceptance Criteria and Reported Device Performance
The document does not explicitly state quantitative acceptance criteria for the MR-Touch™ Option in terms of clinical performance metrics (e.g., sensitivity, specificity, accuracy) for a specific diagnostic task. Instead, the "acceptance" is based on demonstrating substantial equivalence to predicate devices and verifying certain functional aspects.
| Acceptance Criterion (Implicit) | Reported Device Performance |
|---|---|
| Functional Equivalence to Existing Phase-Contrast Imaging | MR-Touch™ is described as an "evolutionary improvement of the existing phase-contrast imaging feature included with existing GE Signa® MR Systems." It offers a "more convenient method to visualize a time-series of phase-contrast images and the ability to induce synchronized vibrations in the scan subject during acquisition." This implies it performs at least as well as, if not better than, the predicate in its core imaging function. |
| Elastography Output Equivalence to Cleared Ultrasound System | The "Elastography relative-stiffness images (Elastograms)" are stated to be "substantially equivalent to the output of the previously cleared Ultrasonix SonixTouch Elastography imaging mode, which provides color-coded images to differentiate between tissues based on stiffness." |
| Repeatability of Results | "Confidence studies prove that MR-Touch™ produces repeatable results." (No specific quantitative metric or range for repeatability is provided). |
| Ability to Differentiate Tissues of Different Stiffness | "Confidence studies prove that MR-Touch™... can reliably differentiate between tissues of different stiffness." (No specific quantitative metric or threshold for differentiation is provided). |
| Safety and Electromagnetic Compatibility (EMC) | The Resoundant hardware was evaluated against IEC 60601-1 (Medical Electrical Equipment - Part 1: General Requirements for Safety standard) and IEC 60601-1-2 (Collateral Standard: Electromagnetic Compatibility - Requirements and Tests - Second Edition with Amendment 1). The conclusion of substantial equivalence implies it met these safety and EMC standards. |
| Image Quality and Visualization | "Sample images demonstrate the strain wave and Elastogram outputs." "When used with a GE Signa® MR system, MR-Touch™ is capable of producing transverse images of internal body structures such as muscle and liver." (This implies adequate image quality for diagnostic interpretation by a trained physician, though specific metrics are absent). |
| Regulatory Substantial Equivalence | The FDA's 510(k) clearance letter confirms that the device is "substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices." This is the ultimate acceptance criterion for a 510(k) submission. |
2. Sample Size and Data Provenance (for test set)
The document is unclear regarding a dedicated "test set" in the context of clinical performance evaluation. The "Summary of Studies" mentions "Sample images" and "confidence studies" but gives no specifics on:
- Sample Size: Not specified for any performance evaluation.
- Data Provenance: Not specified (e.g., country of origin, retrospective or prospective). It is common for 510(k) submissions, especially for accessories and evolutionary improvements, to rely on internal testing, phantoms, and existing predicate device performance rather than large-scale clinical studies.
3. Number and Qualifications of Experts for Ground Truth
- Number of Experts: Not specified.
- Qualifications of Experts: Not specified.
- Ground Truth Establishment: The document does not describe how ground truth was established for any "test set." The statement "When interpreted by a trained physician, these images may provide information that can be useful in determining a diagnosis" suggests diagnostic interpretation by a physician is the intended clinical use, but this is not defined as a ground truth mechanism for device validation.
4. Adjudication Method
Not discussed or specified. Given the nature of the submission (substantial equivalence based on technical and functional similarity rather than a new clinical claim requiring high-stakes diagnostic accuracy), a formal adjudication method for a test set is unlikely to have been implemented or required.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study is mentioned. The submission focuses on the device's technical performance and equivalence to existing technologies, not on improving human reader performance with or without AI assistance. The "AI" component here is the image processing and reconstruction software, not a diagnostic AI intended to aid human readers.
6. Standalone Performance Study
The "Summary of Studies" section describes "confidence studies" that "prove that MR-Touch™ produces repeatable results and can reliably differentiate between tissues of different stiffness." This inherently evaluates the standalone performance of the algorithm in generating the strain wave and elastogram outputs. However, specific performance metrics (e.g., accuracy against a known stiffness standard, precision) are not provided. The study does not describe a "human-in-the-loop" component for these specific tests, making them standalone evaluations of the device's ability to produce consistent and differentiate images.
7. Type of Ground Truth Used
For the "confidence studies" demonstrating repeatability and differentiation of stiffness, the ground truth would most likely have been:
- Phantom Studies: Using materials with known and varied stiffness properties.
- Known Physical Properties: Measuring the physical properties of the materials used in the "confidence studies" (e.g., using a mechanical testing device to confirm differences in stiffness).
- The document implies the output (elastograms) themselves are the useful information, rather than a comparison to an external clinical ground truth like pathology or outcomes data.
8. Sample Size for the Training Set
The document does not mention any "training set" in the context of machine learning. The MR-Touch™ system is described as an "evolutionary improvement" to existing gradient echo sequences and phase-contrast imaging, implying traditional image processing and reconstruction algorithms rather than a deep learning model that requires a labeled training set.
9. How Ground Truth for the Training Set Was Established
Not applicable, as no training set for machine learning is described.
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