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The device is designed to perform radiographic x-ray examinations on pediatric and adult patients treatment areas.

Carestream Health, Inc. is submitting this Traditional 510(k) premarket notification for a modification to the cleared DRX-Revolution Nano Mobile X-ray System (K170755). The product will continue to be marketed as the DRX-Revolution Nano Mobile X-ray System. Consistent with the original system, the modified DRX-Revolution Nano Mobile X-ray System (also referred to throughout this document as the Nano system) is a diagnostic mobile x-ray system utilizing digital radiography (DR) technology. The system consists of a self contained x-ray generator, image receptor(s), imaging display and software for acquiring medical diagnostic images outside of a standard stationary x-ray room. The modified Nano system can also be used to expose Computed Radiography (CR) storage phosphor or film cassettes. Modifications have been made to the design of the system's x-ray tube and its operational characteristics for the purpose of improving the x-ray tube reliability and life span. This required modifications to the embedded software to accommodate these tube design changes.

This document describes the validation study for the DRX-Revolution Nano Mobile X-ray System, which involved modifications to the x-ray tube and software. The study's primary goal was to demonstrate that the modified device performs as well as or better than its predicate device with respect to diagnostic image quality.

1. Acceptance Criteria and Reported Device Performance

2. Sample size used for the test set and the data provenance

• Sample size for the test set: 60 RadLex ratings (from 3 radiologists, each rating a set of images, totaling 60 individual responses). The number of unique images or cases is not explicitly stated, but it can be inferred that there were at least 20 images/cases if each radiologist rated all the same images.
• Data provenance: Prospective, synthetic data using anthropomorphic phantoms. The phantoms included commercial products representing various human anatomical sections (adult chest "Lungman," adult pelvis, upper and lower limbs of a 5-year-old child, and a Gammex 610 neonatal chest phantom). Additional PMMA plates were used to simulate larger adult patients. The country of origin of the data is not specified beyond the manufacturers of the phantoms (Kyoto Kagaku for Lungman, CIRS Inc for child phantoms, Supertech for neonatal phantom).

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

• Number of experts: Three (3) board-certified radiologists.
• Qualifications of experts: "Three (3) board certified radiologists with extensive reading experience." Specific years of experience are not provided.

4. Adjudication method for the test set

• The radiologists provided independent ratings (single stimulus format) on a work list of images.
• There is no explicit mention of an adjudication method for disagreements between readers; rather, the statistical analysis (ANOVA) was used to determine if there was a significant difference between reader ratings. The finding was that "There is no significant difference in ratings across Readers," implying sufficient agreement for the purpose of the study.

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, a multi-reader, multi-case (MRMC) comparative effectiveness study comparing human readers with AI assistance versus without AI assistance was explicitly done. This study focused on the image quality of the device itself using human readers as evaluators, not on the impact of AI assistance on human reader performance.

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

• No, an algorithm-only standalone performance study was not done. The study evaluated the diagnostic imaging performance of the system by using human radiologists to rate the images. The device itself is an X-ray system, not an AI algorithm for image interpretation.

7. The type of ground truth used

• The ground truth in this study was expert consensus rating by multiple radiologists, rather than an objective "true" diagnosis or pathology. The images were generated from anthropomorphic phantoms (synthetic data), so there was no "patient outcome" or "pathology" data to serve as ground truth in a clinical sense. The "ground truth" for the acceptance criteria was the radiologists' ratings on the RadLex scale.

8. The sample size for the training set

• Not applicable / not provided in the input. This study describes the validation of an X-ray system after modifications to its hardware and embedded software. It is not an AI algorithm study that typically involves a training set and a separate test set. The "training" for such a system would involve engineering and development, not data-driven machine learning as understood in AI contexts.

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

• Not applicable / not provided in the input. As noted above, this isn't an AI study with labeled training data.

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The device is designed to perform radiographic x-ray examinations on adult patients, in all patient treatment areas.

The device is designed to perform radiographic x-ray examinations on pediatric and adult patients, in all patient treatment areas.

The DRX-Revolution Nano Mobile X-ray System (also referred to as the DRX-Revolution Nano) is a diagnostic mobile x-ray system utilizing digital radiography (DR) technology. The system consists of a self contained x-ray generator, image receptor(s), imaging display and software for acquiring medical diagnostic images outside of a standard stationary x-ray room. The DRX-Revolution Nano system can also be used to expose CR storage phosphor screen or film cassettes.

Here's an analysis of the provided text, focusing on the acceptance criteria and the study details:

Overall Assessment: The provided document is a 510(k) premarket notification for the DRX-Revolution Nano Mobile X-ray System. It describes the device, its intended use, comparison to a predicate device, and performance testing. The clinical study mentioned is a comparative effectiveness study designed to show non-inferiority to the predicate device, not a standalone study demonstrating specific performance metrics against a defined acceptance criterion. The key takeaway is that the diagnostic capability of the new device is statistically equivalent to or better than the predicate.

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state quantitative acceptance criteria for the diagnostic performance of the DRX-Revolution Nano itself, nor does it list specific performance metrics like sensitivity or specificity. Instead, the "acceptance criterion" for the clinical study was to demonstrate statistical equivalence or superiority in diagnostic capability compared to the predicate device.

Note: The document primarily focuses on demonstrating substantial equivalence to a predicate device rather than meeting specific quantitative diagnostic performance thresholds as might be defined for a novel AI algorithm.

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

• Sample Size for Test Set:
  • Clinical Study: "Adult cadavers were used to perform pair-wise investigational vs. predicate acquisitions using similar radiographic techniques and body positioning for 2D imaging."
    • The specific number of adult cadavers is not provided.
    • The images included targeting various exam types such as chest, abdomen, skull, C-spine, L-spine, pelvis, hip, nasal bones, shoulder, and extremity radiographs.
  • Pediatric Phantom Images: "In addition, eight pediatric phantom images were acquired on both the investigational and predicate devices in the laboratory at Carestream Health, Inc."
    • This suggests 8 unique pediatric phantom images were taken with both devices, resulting in 16 total images from phantoms.
• Data Provenance:
  • Adult Cadaver Images: Not explicitly stated, but implies the studies were conducted by Carestream Health. Not specified if retrospective or prospective, but likely acquired prospectively for the study.
  • Pediatric Phantom Images: Acquired in the laboratory at Carestream Health, Inc. (Prospective).

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

The document mentions a "Reader Study" but does not specify the number or qualifications of the experts/readers who established the (presumably diagnostic) ground truth for the test set.

4. Adjudication Method for the Test Set

The document states: "The images were assembled and reviewed in a single stimulus random format in order to perform a Comparative Evaluation to statistically confirm the findings of this evaluation."

This describes the presentation format to the readers but does not specify an adjudication method for establishing a consensus ground truth (e.g., 2+1, 3+1). It implies readers were evaluating images against each other (investigational vs. predicate) rather than against an independently established ground truth.

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

• MRMC Comparative Effectiveness Study: Yes, a comparative study was performed between the DRX-Revolution Nano (investigational) and the DRX-Revolution Mobile X-ray System (predicate). The images were reviewed by readers (implied by "Reader Study").
• Effect Size of Human Readers with AI vs. Without AI Assistance: This question is not applicable here. The DRX-Revolution Nano is an X-ray imaging system, not an AI-powered diagnostic algorithm designed to assist human readers. The study compares the imaging performance of two different X-ray systems.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

This question is not applicable. The device is a mobile X-ray system, not a standalone algorithm. The clinical study evaluated the imaging performance and diagnostic capability of the system in producing images that radiologists would interpret, not an algorithm's performance independent of human interpretation.

7. The Type of Ground Truth Used

The document does not explicitly state the specific type of ground truth used (e.g., pathology, clinical outcomes, expert consensus) for the diagnostic capabilities evaluated in the reader study. It implies that the "diagnostic capability" was assessed by human readers comparing "investigational vs. predicate acquisitions." It's likely that the readers' interpretations, potentially against a "reference standard" if established per case, formed the basis, but this is not detailed.

8. The Sample Size for the Training Set

This question is not applicable. The DRX-Revolution Nano is a hardware X-ray system with embedded software for image acquisition and processing. It is not described as an AI/ML algorithm that requires a "training set" for diagnostic decision-making. The software verification and validation section indicates testing was done on the embedded software for its functionality and safety, not for a learning model.

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

This question is not applicable for the same reasons as point 8.

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