(38 days)
The Varex Nexus DR Digital X-ray Imaging System is a high resolution digital imaging system intended to replace conventional film techniques, or existing digital systems, in multipurpose or dedicated applications specified below. The Nexus DR Digital X-ray Imaging System enables an operator to acquire, display, process, export images to portable media, send images over a network for long term storage and distribute hard-copy images with a laser printer. Image processing algorithms enable the operator to bring out diagnostic details difficult to see using conventional imaging techniques. Images can be stored locally for temporary storage. The major system components include an image receptor, computer, monitor and imaging software.
The Varex Nexus DR Digital X-ray Imaging System is intended for use in general radiographic examinations and applications (excluding fluoroscopy, angiography, and mammography).
The Varex Nexus DR. Digital X-ray Imaging System is a high resolution digital imaging system designed for digital X-ray imaging through the use of an X-ray detector. The Nexus DR. Digital X-ray Imaging System is designed to support general radiographic (excluding fluoroscopy, angiography, and mammography) procedures through a single common imaging platform.
The modified device consists of an X-ray imaging receptor, computer, monitor, and the digital imaging software and the optional Integrated Generator GUI software.
The Varex Nexus DR. Digital X-ray Imaging System is a configurable product platform designed to allow Varex to leverage the common components of digital X-ray imaging systems from which the following medical modalities can be served: General Radiography (excluding fluoroscopy, angiography, and mammography). The Nexus DR. Digital X-ray Imaging System is then configured to function on a computer with modality specific components, functionality and capabilities to complete the specific product package.
Like the predicate device, the modified Nexus DR. Digital X-ray Imaging System is in a class of devices that all use similar technology to acquire digital radiographic images. These devices convert X-rays into visible light that shines onto a TFT array, which converts the visible light into a digital electronic signal. This process is ultimately used for the same purpose as Radiographic film, to create an X-ray image.
Identical to the predicate device, the modified device is capable of interfacing with flat panel detectors in RAD Mode without utilizing an external I/O box to interface with the X-ray generator. The modified device also retains the ability to apply the grid suppression feature.
Similar to the already cleared Nexus DR™ Digital X-ray Imaging System with Stitching and CPI Rad Vision the modified device, Nexus DR™ Digital X-ray Imaging System (with Integrated Generator), has the same intended use for the DR application. The modified device, however, has the ability to allow the operator to control the CPI CMP200 X-ray generator through the Nexus DR™ Graphical User Interface (GUI). All control functions currently available to the operator on the CPI Membrane Rad Console will be available via the Nexus DR GUI. The Nexus DR Digital X-ray Imaging System can then store the images on the local computer, archive them to CD/DVD media, transfer them to Hard Copy format via DICOM printers, or transfer them to PACS reviewing stations in DICOM format.
Here's an analysis of the acceptance criteria and study information based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The provided document describes non-clinical verification and validation testing, but it does not specify quantitative acceptance criteria in a table format with corresponding reported performance metrics. Instead, it states that "All associated tests described above completed successfully without errors and the both devices preformed as intended. In conclusion, all release criteria have been met..."
However, based on the description of the testing, we can infer the types of acceptance criteria that would have been used:
| Acceptance Criteria Type | Reported Device Performance (Inferred from text) |
|---|---|
| Verification Testing (Technical Functionality) | |
| Generator Configuration Service Settings | Confirmed technical functionality of configuring the generator. |
| Acquisition Profile Generator Settings | Confirmed technical functionality of configuring and modifying acquisition profile generator settings. |
| Image Acquisition | Confirmed technical functionality of image acquisition. |
| Full System Regression | Successfully completed with no errors. |
| Validation Testing (Clinical Workflow) | |
| Initial Generator Settings/Exposure Factors | Confirmed correct initial generator settings or exposure factors upon opening new patient study in combination with other Nexus DR functions (Worklist Patients with Multiple Studies, Auto Position Advance, Auto DICOM Send). |
| Detector Selection (Active Generator Workstation) | Confirmed correct detector selection based on the active generator workstation in combination with other Nexus DR functions. |
| Display of Generator Data in Image Overlay | Confirmed display of generator data (Workstation, focal spot, exposure mode, and technique factors) in the image overlay after image acquisition completed, in combination with other Nexus DR functions. |
| Usability Testing | Performed and results can be found in VOL 011 Appendix K Validation Tests. (Specific performance metrics are not described in the provided text, but the overarching conclusion is that "all release criteria have been met" and the device performed as intended, implying successful usability performance.) |
| Safety and Effectiveness Equivalence | "Nexus DR. Digital X-ray Imaging System (with Integrated Generator) has no new indications for use, has no significant technological differences, and is as safe and effective as, does not raise different questions of safety and effectiveness and is therefore substantially equivalent to the above listed current legally marketed predicate device." (This is the ultimate regulatory-level conclusion, not a specific performance metric, but it indicates the device met criteria for equivalence.) |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The document does not specify a numerical sample size for the test set used in the non-clinical verification and validation testing. It mentions "simulated (bench test) clinical environment" and "standard clinical workflow" without detailing the number of test cases or scenarios.
- Data Provenance: The testing was conducted in a "simulated (bench test) clinical environment." This indicates the data was not from actual patient data but rather from controlled, simulated scenarios. The country of origin is not explicitly stated beyond Varex Imaging Corporation being in Liverpool, NY, USA, which implies the testing was likely conducted in the USA. The testing was prospective in the sense that it was specifically designed and executed for the purpose of validating the device's integrated generator feature.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not mention the use of experts to establish ground truth for the test set. The validation appears to be functional and workflow-based rather than diagnostic performance-based, meaning the "ground truth" was likely defined by the expected functional behavior and correct display/control outcomes as per the design requirements.
4. Adjudication Method for the Test Set
No explicit adjudication method is mentioned. Given that the testing focused on functional verification and workflow validation in a simulated environment, adjudication by subject matter experts (like radiologists for diagnostic decisions) would not be applicable in the way it is for diagnostic AI performance studies. The tests were designed with "predetermined test methods and corresponding acceptance criteria," suggesting an objective pass/fail determination based on those criteria.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
No. The document explicitly states: "No clinical testing was performed as a result of this modification." Therefore, no MRMC study, or any clinical comparative effectiveness study involving human readers or AI assistance effect size, was conducted or reported.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done
No, this device is an X-ray imaging system with an integrated generator. It is a hardware and software system designed to acquire and process radiographic images, not a standalone AI algorithm for interpretation or diagnosis. The "algorithm" here refers to image processing algorithms within the system, but their performance isn't evaluated as a standalone AI diagnostic tool. The focus is on the system's functional equivalence and safety/effectiveness in acquiring and displaying images.
7. The Type of Ground Truth Used
The "ground truth" for the non-clinical verification and validation testing was based on design requirements and expected functional behavior. For example, the ground truth for "initial generator settings" would be the correct settings as defined by the system's design and user input, not a clinical diagnosis or pathology.
8. The Sample Size for the Training Set
Not applicable. This document describes the testing and clearance of an X-ray imaging system with an integrated generator, not an AI/machine learning model that requires a training set. The "image processing algorithms" are likely deterministic or rule-based, not AI trained on large datasets.
9. How the Ground Truth for the Training Set Was Established
Not applicable for the same reason as point 8.
§ 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.