(99 days)
The EVS 4343 and EVS 4343G Digital X-ray detector is indicated for digital imaging solution designed for providing general radiographic diagnosis of human anatomy. This device is intended to replace film or screen based radio graphic systems in all general purpose diagnostic procedures. This device is not intended for mammography applications.
The EVS 4343(G) is a wired flat-panel type digital X-ray detector that captures projection radiographic images in digital format within seconds, eliminating the need for an entire x-ray film or an image plate as an image capture medium. EVS 4343(G) differs from traditional X-ray systems in that, instead of exposing a film and chemically processing it to create a hard copy image, a device called a Detector is used to capture the image in electronic form.
The EVS 4343(G) Detector is an indirect conversion device in the form of a square plate in which converts the incoming X-rays into visible light. This visible light is then collected by an optical sensor, which generates an electric charges representation of the spatial distribution of the incoming X-ray quanta.
The charges are converted to a modulated electrical signal thin film transistors. The amplified signal is converted to a voltage signal and is then converted from an analog to digital signal which can be transmitted to a viewed image print out, transmitted to remote viewing or stored as an electronic data file for later viewing.
1. Table of Acceptance Criteria and Reported Device Performance:
The document indicates that the acceptance criteria are based on equivalence to predicate devices (K142475 and K150766). The study aimed to demonstrate that the new detectors provide "images of equivalent diagnostic capability." While specific numeric acceptance thresholds are not explicitly stated, the performance metrics (DQE and MTF) are compared against the predicate devices.
| Parameter | Acceptance Criteria (Predicate) | Reported Device Performance (EVS 4343) | Reported Device Performance (EVS 4343G) | Remark |
|---|---|---|---|---|
| DQE | K142475: 28% at 1 lp/mm, 13% at 3 lp/mm | 43.9% at 1 lp/mm, 16.5% at 3 lp/mm | 23.6% at 1 lp/mm, 5% at 3 lp/mm | Similarity |
| (Detective | K150766: 29.7% at 1 lp/mm, 5.0% at 3 lp/mm | |||
| Quantum | ||||
| Efficiency) | ||||
| MTF | K142475: 35% at 2.0 lp/mm | 35% at 2.0 lp/mm | 34% at 2.0 lp/mm | Same |
| (Modulation | K150766: 17.4% at 2.0 lp/mm | |||
| Transfer | ||||
| Function) | ||||
| Resolution | 3.5 lp/mm (for both predicates and new devices) | 3.5 lp/mm | 3.5 lp/mm | Same |
Note regarding DQE: While the "Remark" column states "similarity," for EVS 4343, the DQE values are higher than both predicates, suggesting better performance. For EVS 4343G, the DQE at 1 lp/mm is lower than both predicates, and at 3 lp/mm, it is the same as K150766 but lower than K142475. The document concludes "similarity," indicating that these differences were deemed acceptable for substantial equivalence.
2. Sample Size Used for the Test Set and Data Provenance:
The document states that a "single-blinded concurrence study" was conducted to confirm "equivalent diagnostic capability" to the predicate devices. However, the sample size for the test set is not explicitly provided.
The data provenance is also not explicitly stated in terms of country of origin or whether it was retrospective or prospective.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications:
The document does not specify the number of experts used or their qualifications for the single-blinded concurrence study. It only mentions that the study was conducted according to "CDRH's Guidance for the Submission of 510(k)'s for Solid State X-ray Imaging Devices."
4. Adjudication Method for the Test Set:
The document mentions a "single-blinded concurrence study." This implies that readers were blinded to the source of the image (test device vs. predicate) and their readings were compared for agreement or concordance. However, the specific adjudication method (e.g., 2+1, 3+1, none) is not detailed.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
The document refers to a "single-blinded concurrence study" to assess "equivalent diagnostic capability," which suggests a type of reader study. However, it does not explicitly state that it was an MRMC comparative effectiveness study in the formal sense, nor does it provide an effect size of how much human readers improve with AI vs. without AI assistance. The device described is an X-ray detector, not an AI-powered diagnostic tool, so the concept of "AI assistance" is not applicable in this context.
6. Standalone Performance Study:
Yes, a standalone study of the algorithm's performance (in this case, the detector's physical performance) was done. The document explicitly includes "Summary of Non-Clinical Data" which reports the DQE (Detective Quantum Efficiency) and MTF (Modulation Transfer Function) values for the EVS 4343 and EVS 4343G devices. These are intrinsic performance characteristics of the detector itself, independent of human interpretation.
7. Type of Ground Truth Used:
For the non-clinical performance data (DQE, MTF), the ground truth is established through physical measurements and international standards (IEC 62220-1 for DQE).
For the "single-blinded concurrence study" assessing "equivalent diagnostic capability," the ground truth implicitly seems to be expert consensus on diagnostic capability comparing images from the new device against images from the predicate devices. However, the specific method for establishing this "ground truth" (e.g., if a definitive diagnosis was available for the cases used) is not detailed.
8. Sample Size for the Training Set:
The document does not provide information on a training set sample size. The EVS 4343(G) is an X-ray detector, a hardware device, not an AI algorithm that typically requires a large training dataset.
9. How Ground Truth for the Training Set Was Established:
As there is no mention of a "training set" for the device itself (being a hardware detector), this question is not applicable based on the provided document. The performance metrics (DQE, MTF) are physical properties measured according to established standards rather than "trained" by data.
§ 892.1680 Stationary x-ray system.
(a)
Identification. A stationary x-ray system is a permanently installed diagnostic system intended to generate and control x-rays for examination of various anatomical regions. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II (special controls). A radiographic contrast tray or radiology diagnostic kit intended for use with a stationary x-ray system only is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.