(267 days)
The OmniTom Elite computed tomography (CT) system is intended to be used for x-ray computed tomography applications for anatomy that can be imaged in the 40cm aperture, primarily head and neck.
The CT system is intended to be used for both pediatric and adult imaging and as such has preset dose settings based upon weight and age. The CT images can be obtained either with or without contrast.
OmniTom Elite with photon counting detectors (PCD) can generate spectral CT images at multiple energy levels. OmniTom Elite with PCD is only supported for adult imaging for anatomy that can be imaged in the 40cm aperture, primarily head and neck.
The subject OmniTom Elite Computed Tomography (CT) system provides the same functionality as the previous version of the device, OmniTom Elite (K202526). We have included some other design changes to make the system more robust and reliable. Both computed tomography systems are identical in terms of the high resolution, 16 row, 40 cm bore, and 30 cm field of view. The lightweight translating gantry consists of a rotating disk with a solid-state x-ray generator, collimator, control computer, communications link, power slip-ring, data acquisition system, reconstruction computer, power system, brushless DC servo drive system (disk rotation) and an internal drive system (translation). The power system consists of batteries which provide system power while unplugged from the charging outlet. The system has the necessary safety features such as the emergency stop switch, x-ray indicators, interlocks, patient alignment laser and 110% x-ray timer. The gantry has omni-directional wheels that allow for robust diagonal, lateral, and rotational 360-degree movement and electrical drive system so the system can be moved easily to different locations.
We have added the ability to upgrade the OmniTom Elite system with photon counting detector (PCD). OmniTom Elite with PCD is the same system as the predicate device OmniTom Elite energy integrating detector (EID) with the only difference being the detector array system, instead of the current gadolinium oxysulfide EID, it has a cadmium telluride based PCD.
PCD provides the ability to capture CT data in multiple energy bands that can provide information on material composition of different tissues and contrast media. The multiple sets of CT data are acquired at the same time with configurable energy thresholds without any cross talk between images. OmniTom Elite with PCD has the capacity to more than double the EID detector spatial resolution.
The provided text describes the OmniTom Elite CT system, which offers an optional Photon Counting Detector (PCD) upgrade. The submission aims to demonstrate substantial equivalence to its predicate device, OmniTom Elite with Energy Integrating Detector (EID) (K202526).
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 acceptance criteria are generally framed around demonstrating the safety, effectiveness, and comparable image quality of the OmniTom Elite with PCD to its EID counterpart, without raising new questions of safety or effectiveness. Specific quantitative acceptance criteria are not explicitly listed in easily consumable metrics such as sensitivity/specificity/accuracy, but rather implied through compliance with standards, successful performance tests, and expert review.
| Acceptance Criteria Category | Description | Reported Device Performance |
|---|---|---|
| Safety | Compliance with relevant electrical safety, radiation safety, and electromagnetic compatibility standards. Risk analysis and mitigation. | - "All components...are certified to meet those requirements [Federal Diagnostic Equipment Performance Standard and 21 CFR §1020.30 and §1020.33]." |
- "NeuroLogica adheres to recognized and established industry practices."
- "OmniTom Elite CT system is designed and manufactured to comply with the FDA Quality System Regulations (21 CFR part 820) and ISO 13485:2016 requirements."
- Conformance with numerous harmonized standards including ISO 14971 (Risk Management), IEC 60601-1 (Basic Safety), IEC 60601-1-2 (EMC), IEC 60601-1-3 (Radiation Protection), IEC 60601-2-44 (CT Equipment Specific), NEMA XR 25, 26, 28, 29, 21 CFR §1020.30, §1020.33.
- "The OmniTom Elite with PCD underwent Electrical Safety and Electromagnetic Compatibility testing and proved to be in compliance with IEC 60601-1, IEC 60601-1-2, and IEC 60601-2-44."
- "The risk management analysis identified potential hazards which were controlled and mitigated during development." |
| Effectiveness/Functionality | Device performs as intended for CT imaging, including new PCD capabilities (multi-energy, spectral CT), without negative impact from design changes. | - "The proposed OmniTom Elite device demonstrated that the new features did not exhibit any negative effects on the requirements in place, as well as they did not exhibit any concerns that may impact safety and effectiveness." - "Software verification and software validation testing was executed to confirm all software requirements were met. The proposed OmniTom Elite device was shown to meet all requirements and to not have any impact on imaging."
- PCD capabilities were tested to demonstrate properties of PCD in count and multi-energy mode. Imaging metrics demonstrated stability of the detector, analysis of the count rate and limited pileup loss at low dose scanning.
- "Comparative study was conducted... The comparative study involved scanning the same subject using both the EID and the PCD CT systems at the same anatomical sections... These images were reviewed by two independent board-certified radiologists and confirmed diagnostic quality of the images demonstrating the effectiveness of the subject device for clinical scanning." |
| Image Quality | Image quality metrics (noise, slice thickness, resolution) are comparable to the predicate device and meet established criteria. | - "Imaging metrics such as noise, slice thickness, low and high contrast resolution, radiation metrics, and modulation transfer function were measured utilizing phantom image quality tests in accordance with the equipment performance standards for diagnostic x-ray systems administered by the FDA." - "Imaging metrics successfully demonstrated that the proposed device with PCD has comparable image quality with its previous version, predicate device (K202526) that had EID and meets all the image quality criteria that are used for testing." |
| PCD Specific Functionality | Ability to generate spectral CT images at multiple energy levels with configurable thresholds, minimal crosstalk, and enhanced spatial resolution for adults in head/neck. Stable detector and acceptable count rate. | - "PCD provides the ability to capture CT data in multiple energy bands that can provide information on material composition... The multiple sets of CT data are acquired at the same time with configurable energy thresholds without any cross talk between images." - "OmniTom Elite with PCD has the capacity to more than double the EID detector spatial resolution."
- "No crosstalk noticed between images."
- "Imaging metrics demonstrated stability of the detector, analysis of the count rate and limited pileup loss at low dose scanning." |
| Usability/Movement Control | Enhanced movement controls for simpler/easier navigation, improved durability, and ease of operator transport. | - "The addition of a drive camera (SmartDrive) and new transport wheels (OmniWheels) for simpler navigation; the drive bar mechanism was enhanced for durability, easier manufacturability and ease of operator overall transportation of device." - "The improvements in movement performance were implemented to solely allow the operator to transport the device with ease." |
| Software Integrity | Software developed and tested in accordance with relevant standards and guidance; no negative impact on imaging. | - "The software contained in the proposed device has been developed & tested in accordance with IEC 62304, and the FDA guidance for Content of Premarket Submissions for Software Contained in Medical Devices." - "Software verification and software validation testing was executed to confirm all software requirements were met."
- "The proposed OmniTom Elite device was shown to meet all requirements and to not have any impact on imaging." |
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Size: The text states, "Volunteers underwent scanning to aid in generation of comparative images." It does not specify the exact number of volunteers. It implies a small number, as it talks about "the same subject" being scanned.
- Data Provenance: Not explicitly stated, but the mention of "an IRB" (Institutional Review Board) implies a prospective study involving human subjects. The country of origin is not specified but is likely the US given the FDA submission. It was a prospective study involving volunteers.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- Number of Experts: "two independent board-certified radiologists."
- Qualifications: "board-certified radiologists." No further details on years of experience are provided, but board certification implies a high level of expertise in medical imaging interpretation.
4. Adjudication Method for the Test Set
The text states: "These images were reviewed by two independent board-certified radiologists and confirmed diagnostic quality of the images demonstrating the effectiveness of the subject device for clinical scanning."
This indicates a consensus or agreement-based approach for diagnostic quality, where both radiologists had to confirm it. There is no mention of a formal adjudication process (e.g., 2+1 or 3+1 where a third or fourth reader resolves discrepancies), beyond the agreement on diagnostic quality. It seems the goal was to confirm diagnostic quality, not necessarily to create a "ground truth" for specific disease detection where adjudication for disagreements would be critical.
5. If a Multi-Reader, Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, a formal MRMC comparative effectiveness study to assess improvement in human readers with AI vs. without AI assistance was not conducted or described. The study described was a comparative imaging study to show that images from the new PCD system were of diagnostic quality and comparable to the EID system. The focus was on the device's image quality and diagnostic utility as a standalone imaging system, not its impact on human reader performance.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Study Was Done
Yes, a standalone assessment was a primary component of the submission. The "Image quality evaluation" section describes rigorous phantom testing and measurements of "noise, slice thickness, low and high contrast resolution, radiation metrics, and modulation transfer function." This demonstrates the algorithm's (and hardware's) performance in generating images. The clinical evaluation with radiologists also served to confirm the diagnostic quality of the images generated by the device itself, implicitly assessing its standalone performance.
7. The Type of Ground Truth Used
The ground truth for the device's image quality and diagnostic utility was established through:
- Phantom Tests: For objective image quality metrics (noise, resolution, MTF, etc.).
- Expert Consensus/Opinion: For confirming the "diagnostic quality" of the clinical images by two independent board-certified radiologists. This isn't a "pathology" or "outcomes data" ground truth, but rather a subjective assessment by experts of the image's clinical utility.
8. The Sample Size for the Training Set
The document does not mention a training set sample size. This is because the device is a CT scanner, not an AI/ML diagnostic algorithm that requires a separate training set of patient data for model development. The "training" here refers to the engineering and validation processes (design verification, software testing, bench testing, etc.) that ensure the system functions correctly and produces high-quality images.
9. How the Ground Truth for the Training Set Was Established
As explained above, there isn't a "training set" in the sense of patient data used to train an AI model. The system's "ground truth" (i.e., its correct operational parameters and expected image output) was established through:
- Engineering Specifications and Design Requirements: What the system was designed to achieve.
- Reference Standards: Adherence to IEC 60601-x standards, NEMA, and FDA performance standards.
- Phantom Studies: Objective measurements against known targets.
- Bench Testing: Verification and validation of hardware and software components against their specified functions.
§ 892.1750 Computed tomography x-ray system.
(a)
Identification. A computed tomography x-ray system is a diagnostic x-ray system intended to produce cross-sectional images of the body by computer reconstruction of x-ray transmission data from the same axial plane taken at different angles. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II.