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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 Nexus DR™ Digital X-ray Imaging System (with vSharp™) is a high resolution digital imaging system designed for digital X-ray imaging through the use of an X-ray detector. Nexus DR™ Digital Xray Imaging System (with vSharp™) 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 vSharp software.

The Nexus DR™ Digital X-ray Imaging System (with vSharp™) 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). Nexus DR™ Digital X-ray Imaging System (with vSharp™) 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 (with vSharp™) 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 v Trigger Mode or RAD Mode utilizing an external I/O box to interface with compatible X-ray generators, in non-integrated mode. 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 Integrated Generator the modified device, Nexus DR™ Digital X-ray Imaging System (with vSharp™), has the same intended use for the DR application. The modified device, however, adds vSharp™ scatter correction algorithm into the Nexus DR Software, the image contrast is enhanced and the images produced have similar detail contrast as images acquired with an anti-scatter grid. 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.

The provided text does not contain detailed information about acceptance criteria and the study that proves the device meets those criteria for the Nexus DR Digital X-Ray Imaging System with vSharp. It mentions "Validation was completed in accordance with the Validation Protocols included with this submission" and "Protocols were designed, executed and documented according to the Design Validation process with predetermined test methods and corresponding acceptance criteria. In conclusion, all release criteria have been met". However, specifics of these protocols, test methods, and the actual performance results against acceptance criteria are not provided.

The document states:

• "No clinical testing was performed as a result of this modification."
• "However, both Usability Testing and Image Comparisons were performed and the results can be found in VOL 018 Appendix R Clinical Data." (This Appendix R is not provided in the input text.)

Therefore, I cannot extract the requested information regarding detailed acceptance criteria, device performance, sample sizes, expert involvement, or grand truth establishment directly from the provided text.

Based on the available information, I can only state that while the document claims acceptance criteria were met and validation was performed, the specifics of these items are not detailed within the provided pages.

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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:

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.

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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 hardcopy 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 DRTM 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 DR-m 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 Stitching software.

The Varex 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 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 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 vTrigger Mode or RAD Mode utilizing an external I/O box to interface with compatible X-ray generators, in non-integrated mode. The modified device also retains the ability to apply the grid suppression feature.

However, the modified device allows the operator to generate sequential radiographic images and electronically join them to create a single electronic image (a leg from hip to foot, for example). Stitching is a post-processing feature that allows the user to merge up to four (4) DICOM images and does not alter the original images. Using a digital flat panel detector, and a non-integrated generator, the Nexus DR Digital X-ray Imaging System (with Stitching) is capable of acquiring multiple digital radiographic images, processing and then displaying them in a high quality single image format to visualize long bones or other anatomical features such as the spine. 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 the study proving the device meets them, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The provided text does not explicitly list quantitative acceptance criteria in a dedicated table format with corresponding reported device performance for the stitching feature. Instead, the document focuses on demonstrating substantial equivalence through a comparison of technological characteristics and a subjective image comparison study.

However, based on the non-clinical and clinical test discussions, we can infer the acceptance criterion to be:

2. Sample Size Used for the Test Set and Data Provenance

• Sample Size: The document states "Previously acquired sequential radiographic images." No specific number or range of images (sample size) is provided for the test set.
• Data Provenance: The images were "Previously acquired sequential radiographic images from the Reference Predicate Device (InfiStitch for i5™ Digital X-Ray Imaging System)." This indicates the data is retrospective, as it was collected prior to the study for the subject device. The country of origin is not specified, but the predicate device's information (K101833) would likely originate from the US given the submission to the FDA.

3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications

The document does not provide details on the number of experts or their qualifications used to establish ground truth for the test set. It only mentions an "image comparison study performed."

4. Adjudication Method for the Test Set

The adjudication method used is not specified. It only states an "image comparison study performed."

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not explicitly stated or implied. The study described is an "image comparison study" to demonstrate substantial equivalence to a reference predicate device, not a comparison of human readers with and without AI assistance.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done

Yes, the "image comparison study" and "bench testing results" described for the stitching feature appear to be a standalone performance evaluation of the algorithm's ability to stitch images, rather than involving human-in-the-loop performance measurement. The critical aspect is the quality and diagnostic utility of the stitched image itself, which is then compared (presumably by experts) to existing stitched images from a predicate device.

7. The Type of Ground Truth Used

The ground truth for the image comparison study was based on previously acquired sequential radiographic images from a legally marketed reference predicate device (InfiStitch for i5™ Digital X-Ray Imaging System). This implies that the accepted output of the predicate device serves as the "ground truth" or standard for comparison against the subject device's stitched images.

8. The Sample Size for the Training Set

The document does not provide any information regarding a training set or its sample size. This is a 510(k) submission for a device incorporating a known function (stitching) onto a new system, not a de novo submission for a novel AI algorithm requiring extensive training data. The stitching logic itself is likely rule-based or uses established image processing techniques rather than machine learning that necessitates a training set.

9. How the Ground Truth for the Training Set Was Established

As no training set is mentioned (see point 8), there is no information on how its ground truth was established.

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The XRpad2 4343 HWC-M, when used with a radiographic imaging system, is indicated for use in generating radiographic images of human anatomy for diagnostic X-ray procedures, wherever conventional screen-film (SF), digital radiography (DR), or computed radiography (CR) systems may be used. It is not intended for mammographic use.

The XRpad2 4343 HWC-M is a wireless, lightweight, cassette-sized, flat panel X-ray detector for digital radiography. It fits into a conventional table or wall-stand Bucky, just like a film-screen cassette. The X-ray detector consists of an amorphous silicon flat panel with a directly deposited Csl:Tl scintillator and dedicated read-out, scan, and control electronics, all packaged in a carbon-fiber and aluminum enclosure. The outside dimensions of the detector are 460 mm × 460 mm × 15.5 mm, which fits into a standard X-ray cassette Bucky.

The detector can be integrated with an X-ray system to enable digital radiography.

The XRpad2 4343 HWC-M device, like the predicate, relies on the X-ray Imaging Software Library (XISL), to control the detector from the host computer. The XISL is a C/C++-coded software library that provides parameterized functions to interface the device to a host work station via an IP Network connection. By use of the application programming interface (API) of XISL one can acquire images and configure all use functions of the XRpad2 4343 HWC-M detector.

The provided text describes the acceptance criteria and the study that proves the device meets the acceptance criteria for the XRpad2 4343 HWC-M Flat Panel Detector.

The acceptance criteria are established by demonstrating substantial equivalence to a predicate device (XRpad2 4336 HWC-M) through non-clinical testing. The key acceptance criteria hinge on the comparability of critical image quality performance attributes and compliance with international and FDA recognized consensus standards.

1. A table of acceptance criteria and the reported device performance

2. Sample sized used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

The document explicitly states: "A clinical study was not required for the XRpad2 4343 HWC-M device." Therefore, there is no test set of clinical images nor data provenance in the traditional sense for evaluation. The "test set" for proving substantial equivalence was the device itself undergoing non-clinical technical testing.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)

Not applicable, as no clinical study or human expert evaluation was used to establish ground truth.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

Not applicable, as no clinical study or human expert evaluation was conducted.

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

Not applicable, as no clinical study, MRMC study, or AI assistance is mentioned. This device is an X-ray detector, not an AI-powered diagnostic tool.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

Not applicable. The study was a non-clinical technical evaluation of the flat panel detector's physical and technical performance attributes like MTF and DQE, not an algorithm.

7. The type of ground truth used (expert concensus, pathology, outcomes data, etc)

The "ground truth" for the non-clinical testing was established by technical measurements and compliance with recognized industry standards (IEC, ISO). For image quality attributes like MTF (Modulation Transfer Function) and DQE (Detective Quantum Efficiency), the 'ground truth' is the quantitative measurement of these physical properties as defined by relevant standards.

8. The sample size for the training set

Not applicable, as this is a physical medical device (X-ray detector), not a machine learning model. There is no concept of a "training set" for this type of device submission.

9. How the ground truth for the training set was established

Not applicable, as there is no training set mentioned.

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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 hardcopy 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, PaxScan 4343RC or PaxScan 4343Rv3, computer, monitor, and the digital imaging 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 DRTM 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 a PaxScan flat panel detector in vTrigger Mode or RAD Mode utilizing an external I/O box to interface with compatible X-ray generators, in non-integrated mode. The modified device also retains the ability to apply the grid suppression feature.

However, the modified device is capable of interfacing with the Varex PaxScan 4343RC and PaxScan 4343Rv3 detectors. The main difference between the additional detector models is mechanical; the PaxScan 4343RC is a cassette-sized portable tethered version whereas the PaxScan 4343v3 is utilized in a fixed configuration. Through the use of a digital flat panel detector, and a non-integrated generator, the Nexus DR™ Digital X-ray Imaging System (with PaxScan 4343RC and PaxScan 4343Rv3) is capable of acquiring digital radiographic images, processing and then displaying them in high quality for clinical diagnosis. 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.

The provided text describes the Varex Nexus DR Digital X-ray Imaging System, which is a digital X-ray imaging system. The submission is for a modified device that interfaces with additional PaxScan detectors compared to the predicate device.

Here's an analysis of the acceptance criteria and study information based on the provided text:

1. A table of acceptance criteria and the reported device performance

The document presents a comparison chart of technological characteristics between the predicate device and the subject device. It doesn't explicitly state "acceptance criteria" in a pass/fail format but rather shows comparative performance metrics, with the implication that "Same" indicates meeting the expectation for substantial equivalence.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

The document explicitly states: "Clinical images were not necessary to establish substantial equivalence based on the modifications to the device (the PaxScan 4343RC and PaxScan 4343Rv3 Flat Panel Detectors use identical technology as the predicate device image detector), and bench testing results provide enough evidence that the subject device works as intended."

This indicates that no clinical test set using patient data was employed for this particular submission. The evaluation was based on non-clinical (bench) testing. Therefore, information on sample size, country of origin, or retrospective/prospective nature of a clinical test set is not applicable.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)

Since no clinical test set was used, there were no experts involved in establishing ground truth for a clinical test set. The evaluation primarily relied on engineering and performance metrics from bench testing.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

Not applicable, as no clinical test set was utilized.

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

Not applicable. The device is an X-ray imaging system, not an AI-based diagnostic tool for interpretation assistance, and no MRMC study was conducted.

6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done

Not applicable. The device is a digital X-ray imaging system; it is not an algorithm for standalone diagnostic performance.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)

For the non-clinical tests, the ground truth was based on engineering specifications, physical measurements, and industry standards (e.g., lp/mm for spatial resolution, QVAL for uniformity, DQE values).

8. The sample size for the training set

Not applicable. The device is a medical imaging hardware system with associated software, not a machine learning algorithm that requires a training set of images in the typical sense. The software aspects would have undergone verification and validation testing, but not "training" with a dataset as an AI algorithm would.

9. How the ground truth for the training set was established

Not applicable, as there was no training set for a machine learning model.

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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 hardcopy 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. Varian PaxScan 4336Wv4, computer, monitor, and the digital imaging 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 the same wireless PaxScan 4336Wv4 flat panel detector in vTrigger Mode.

However, the modified device is also capable of operating in RAD Mode utilizing an external I/O box to interface with compatible X-ray generators, in non-integrated mode. Through the use of a digital flat panel detector, and a non-integrated generator, the Nexus DR™ Digital X-ray Imaging System (with Grid Suppression) is capable of acquiring digital radiographic images, processing and then displaying them in high quality for clinical diagnosis. 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.

Anti-scatter grids play an important role for enhancing image quality in radiography by transmitting a majority of primary radiation and selectively rejecting scattered radiation. When anti-scatter grids are utilized by the end user, the modified device includes an additional feature that can detect and suppress the line artifacts caused by these grids.

This FDA 510(k) K171138 submission describes the Varex Nexus DR™ Digital X-ray Imaging System, specifically focusing on the addition of a 'Grid Suppression' feature. The submission aims to demonstrate substantial equivalence to a previously cleared device (K161459).

Here's an analysis of the acceptance criteria and study information provided:

1. Table of Acceptance Criteria and Reported Device Performance:

The document primarily focuses on demonstrating that the new feature (Grid Suppression) does not negatively impact the existing performance characteristics and that the device remains substantially equivalent to its predicate. Therefore, the "acceptance criteria" discussed are largely qualitative and related to maintaining equivalence rather than new quantitative performance metrics for the grid suppression itself.

The acceptance criteria throughout the document for the new Grid Suppression feature and RAD Mode are primarily based on maintaining the existing safety and effectiveness and image quality characteristics of the predicate device, while the new features perform their intended function (e.g., suppressing grid lines, interfacing with generators). The study relies on non-clinical bench testing to demonstrate this.

2. Sample Size Used for the Test Set and Data Provenance:

The document states: "Non-clinical Data submitted is consistent with FDA guidance document... Validation was completed in accordance with the Validation Protocols included with this submission. Protocols were designed, executed and documented according to the Design Validation process with predetermined test methods and corresponding acceptance criteria."

• Sample Size: Not explicitly stated for specific tests. The validation likely involved a sufficient number of test cases and images to demonstrate the functionality and non-degradation of image quality due to the new features. Given it's non-clinical, controlled test images/data would have been used.
• Data Provenance: The data is generated from non-clinical bench testing and validation. It is prospective in the sense that the testing was performed specifically for this submission. The country of origin of the data is not specified but is presumed to be from Varex Imaging Corporation's testing facilities.

3. Number of Experts Used to Establish Ground Truth and Qualifications:

• Not Applicable. This submission relies on non-clinical testing and benchmarking against the predicate device's established performance metrics. Clinical images and expert review for ground truth are explicitly stated as not necessary to establish substantial equivalence for the modifications.

4. Adjudication Method for the Test Set:

• Not Applicable. Since clinical experts were not used to establish ground truth for this non-clinical submission, no adjudication method was employed.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:

• No. An MRMC study was not conducted. The document explicitly states: "Clinical images were not necessary to establish substantial equivalence based on the modifications to the device (the PaxScan 4336Wv4 Flat Panel Detector uses identical technology as the predicate device image detector), and bench testing results provide enough evidence that the subject device works as intended."
• Effect Size: Not applicable as no such study was performed.

6. Standalone (Algorithm Only) Performance:

• Yes, implicitly. The grid suppression feature is described as "an intuitive software algorithm to detect and suppress the line artifacts caused by anti-scatter grids." The validation testing, being non-clinical, would have assessed the performance of this algorithm in a standalone manner (i.e., algorithm only without human-in-the-loop performance evaluation) to confirm its effectiveness in suppressing grid lines without introducing new artifacts or degrading image quality. The performance metrics listed (spatial resolution, SNR, MTF, DQE maintain "Same") indicate that the overall system performance, even with the new algorithm, remained consistent with the predicate.

7. Type of Ground Truth Used:

• Benchmarking/Predicate Device Equivalence (established performance metrics). For the core imaging performance metrics (Spatial Resolution, SNR, MTF, DQE, etc.), the ground truth is the established performance of the predicate device, which the modified device is shown to match. For the new grid suppression feature, the "ground truth" would be the successful removal of grid artifacts from test images while preserving diagnostic quality, as determined by technical validation protocols.

8. Sample Size for the Training Set:

• Not explicitly stated. The document refers to "an intuitive software algorithm" for grid suppression. For such an algorithm, a training set would likely be used during its development. However, the specific size of this training set is not disclosed in the provided FDA summary.

9. How Ground Truth for the Training Set Was Established:

• Not explicitly stated in the provided document. If machine learning was involved in developing the "intuitive software algorithm" for grid suppression, the training set ground truth would typically be established by presenting the algorithm with a dataset of images, some with grid artifacts and some without, and potentially images where the presence/absence of grid lines and their characteristics have been manually labeled or synthetically generated. This is standard algorithm development practice, but the specifics are not detailed in this 510(k) summary.

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