(83 days)
The production of a series of images of the heart at different phases of the cardiac cycle.
The modification is a cardiac gating technique referred to as Retrospective Gating. In standard cardiac gating, the acquisition is triggered by the QRS pulse of the ECG. In Retrospective Gating, the scan runs continuously, and the correlation with the QRS cycle is done after the fact. This modification does not involve any changes to the existing hardware of the predicate devices.
The provided 510(k) summary for Elscint's "Retrospective Gating for Elscint MRI Systems" describes a modification to existing MRI systems. However, its focus is on demonstrating substantial equivalence to predicate devices rather than proving the device meets specific performance acceptance criteria through a detailed study.
Here's an analysis of the submission based on your request, highlighting what is and isn't available:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Safety Parameters Unchanged: SAR, dB/dt, Bo, acoustic noise, electrical, mechanical, biocompatibility, and software hazards. | "The MRI safety parameters, SAR, dB/dt, Bo, and acoustic noise, are unchanged by the current modification." |
| "Electrical, mechanical, and biocompatibility safety issues are unchanged by the current modification." | |
| "No new software hazards have been introduced, so the software level of concern remains minor." | |
| Effectiveness - Image Comparability: Retrospective Gating option produces images comparable with those produced using standard cardiac gating. | "The MRI performance parameters remain unchanged. The Retrospective Gating option produces images that are comparable with those produced using the standard cardiac gating technique." |
2. Sample Size Used for the Test Set and Data Provenance
- Not explicitly stated. The submission mentions image comparability to existing techniques but does not quantify the sample size (number of patients/scans) used to assess this comparability.
- Data Provenance: Not explicitly stated. Given it's a 510(k) for a device modification, it's likely the "comparable images" refer to internal testing performed by Elscint. It does not specify country of origin or whether it was retrospective or prospective data.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
- Not applicable / Not explicitly stated. The submission focuses on demonstrating safety and "comparable" image quality to an existing method, implying visual assessment by company engineers/experts. There is no mention of independent experts establishing ground truth for a test set.
4. Adjudication Method for the Test Set
- Not applicable / Not explicitly stated. No formal adjudication method is described, as the study design for evaluating "comparability" is not detailed.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done, Effect Size
- No. A formal MRMC comparative effectiveness study, as understood in current regulatory submissions for AI/CAD devices, was not performed or described. This submission predates the widespread use of such studies for AI evaluation in medical imaging. The submission simply states images are "comparable" to standard gating.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Yes, implicitly. This is a modification to an MRI system's acquisition technique, not an AI/CAD algorithm that provides diagnoses or measurements. The "performance" being evaluated is the direct output of the modified MRI system (the images themselves). The statement "The Retrospective Gating option produces images that are comparable with those produced using the standard cardiac gating technique" implies a standalone assessment of the image quality produced by the system.
7. The Type of Ground Truth Used
- Implied Expert Observation/Standard of Care: The "ground truth" here is the established quality and diagnostic utility of images produced by the standard cardiac gating technique. The new technique simply needed to demonstrate that its output images were similar in quality and diagnostic information. This would have been assessed by developers and possibly clinical collaborators comparing the two sets of images. It's not "pathology" or "outcomes data" in the typical sense for a diagnostic algorithm, but rather a performative comparison to an existing, validated imaging method.
8. The Sample Size for the Training Set
- Not applicable / Not explicitly stated. This device modification is to an MRI acquisition technique, not an AI / machine learning algorithm that requires a "training set" in the modern sense. The term "training set" is not relevant to this submission.
9. How the Ground Truth for the Training Set was Established
- Not applicable. As this is not an AI/ML device, there is no "training set" or corresponding ground truth establishment process in this context.
Summary of the Study:
The "study" described in the 510(k) summary is a comparative assessment aimed at demonstrating substantial equivalence to predicate devices. It's not a formal, quantitative performance study with specific metrics, statistical power, and independent adjudication typically seen for novel diagnostic devices. Instead, it relies on proving that the new "Retrospective Gating" technique maintains the same safety profile and produces comparable image quality to established cardiac gating methods within Elscint's existing MRI systems (Gyrex 2T Prestige, Gyrex Privilege, Gyrex Prima 1 TG System). The critical assertion is that "the effectiveness of the modified devices is similar to that of the predicate devices." No detailed study protocol, data, or statistical analysis is provided in this summary. It's a high-level claim of equivalence.
§ 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.