(40 days)
The device is intended to capture for display radiographic images of human anatomy including both pediatric and adult patients. The device is intended for use in general projections wherever conventional screen-film systems or CR systems may be used. Excluded from the indications for use are mammography, fluoroscopy, and angiography applications
The modified DRX Plus 3543C is a scintillator-photodetector device (Solid State X-ray Imager) utilizing an amorphous silicon flat panel image sensor. The modified detector is redesigned with the intent to reduce weight and increase durability, while utilizing a non-glass substrate material and cesium iodide scintillator. The modified detector, like the predicate is designed to interact with Carestream's DRX-1 System (K090318).
The modified DRX Plus 3543C Detector, like the predicate, creates a digital image from the x-rays incident on the input surface during an x-ray exposure. The flat panel imager absorbs incident x-rays and converts the energy into visible light photons. These light photons are converted into electrical charge and stored in structures called "pixels." The digital value in each pixel of the image is directly related to the intensity of the incident x-ray flux at that particular location on the surface of the detector. Image acquisition software is used to correct the digital image for defective pixels and lines on the detector, perform gain and offset correction and generate sub-sampled preview images
The provided text describes a 510(k) submission for a medical device, the Lux 35 Detector, which is a digital X-ray flat panel detector. The submission aims to demonstrate substantial equivalence to a predicate device (DRX Plus 3543 Detector). The information focuses on design modifications and non-clinical testing.
Here's an analysis of the acceptance criteria and study details based on the provided text, highlighting where information is present and where it is not:
Device: Lux 35 Detector (Carestream Health, Inc.)
Study Type: Non-clinical (bench) testing, specifically a Phantom Image Study, to demonstrate substantial equivalence of image quality to a predicate device.
1. Table of Acceptance Criteria and Reported Device Performance:
The document doesn't explicitly state "acceptance criteria" for image quality in a tabular format with pass/fail thresholds. Instead, it provides a qualitative comparison of image attributes. The closest interpretation of "acceptance criteria" is that the modified device's image quality needed to be "equivalent to just noticeably better than" the predicate.
| Acceptance Criterion (Inferred) | Reported Device Performance (Lux 35 Detector vs. Predicate) |
|---|---|
| Image Detail Performance | Ratings for detail were "significantly greater than 0," indicating images were equivalent to or better than predicate. |
| Image Sharpness Performance | Ratings for sharpness were "significantly greater than 0," indicating images were equivalent to or better than predicate. |
| Image Noise Performance | Ratings for noise were "significantly greater than 0," indicating images were equivalent to or better than predicate. |
| Appearance of Artifacts | Qualitative assessment, results not numerically quantified but implied to be equivalent or better given overall conclusion. |
| DQE (Detective Quantum Efficiency) | 55% (RQA-5, 1 cycle/mm, 2.5 µGy) for Lux 35 vs. 26% (RQA-5, 1 cycle/mm, 3.1 µGy) for Predicate. This represents "improved image quality." |
| MTF (Modulation Transfer Function) | 62% (RQA-5, 1 cycle/mm) for Lux 35 vs. 54% (RQA-5, 1 cycle/mm) for Predicate. This represents "improved image quality." |
| Overall Image Quality Comparison | "Greater than 84% of all responses were rated 0 or higher in favor of the modified DRX Plus 3543C panel." "All ratings for the attributes (detail contrast, sharpness and noise) were significantly greater than 0 indicating that the modified DRX Plus 3543C images were equivalent to just noticeably better than the predicate images." "The image quality of the modified device is at least as good as or better than that of the predicate device." |
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size: Not explicitly stated. The text mentions "a Phantom Image Study" but does not quantify the number of images or runs.
- Data Provenance: This was a non-clinical bench testing study using phantoms. Therefore, there is no patient data or geographical provenance. The study was likely conducted at Carestream's facilities. It is a prospective study in the sense that the testing was performed specifically for this submission.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of Experts:
- Number of Experts: Not specified. The text mentions "Greater than 84% of all responses were rated 0 or higher," implying a group of evaluators, but their number is not provided.
- Qualifications of Experts: Not specified. It's unclear if these were radiologists, imaging scientists, or other relevant personnel.
4. Adjudication Method for the Test Set:
- Adjudication Method: Not specified. The phrase "Greater than 84% of all responses were rated 0 or higher" suggests individual ratings were collected, but how conflicts or multiple ratings were aggregated or adjudicated is not detailed.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done:
- Answer: No. The study was a "Phantom Image Study" focused on technical image quality attributes, not human reader performance.
- Effect Size of Human Readers: Not applicable, as no MRMC study was performed.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done:
- Answer: Yes, in a sense. The evaluation of DQE and MTF are standalone technical performance metrics of the detector itself, independent of human interpretation. The "Phantom Image Study" also evaluates the output of the device (images) based on technical attributes, rather than a human diagnostic task.
7. The Type of Ground Truth Used:
- Type of Ground Truth: For the phantom image study, the "ground truth" for evaluating image quality attributes (detail, sharpness, noise, artifacts) is based on technical image quality metrics (DQE, MTF) and potentially expert consensus on visual assessments of phantom images against known ideal phantom characteristics. It is not based on patient outcomes, pathology, or clinical diagnoses.
8. The Sample Size for the Training Set:
- Sample Size for Training Set: Not applicable. This device is a hardware component (X-ray detector) and the study described is a non-clinical evaluation of its image quality, not an AI/algorithm that requires a training set of data.
9. How the Ground Truth for the Training Set Was Established:
- Ground Truth Establishment for Training Set: Not applicable, as this is not an AI/algorithm that requires a training set.
§ 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.