(58 days)
The GE Discovery NM/CT 670 CZT system is a medical tool intended for use by appropriately trained healthcare professionals to aid in detecting, diagnosing of diseases and organ function for the evaluation of diseases, trauma, abnormalities, and disorders such as, but not limited to, cardiovascular disease, neurological disorders and cancer. The system output can also be used by the physician for staging of tumors, planning, guiding, and monitoring therapy. The GE Discovery NM/CT 670 CZT system, combining a CZT-based, high energy and spatial resolution, Nuclear Medicine (NM) system and a Computed Tomography (CT) system, is intended to produce:
· NM System: General Nuclear Medicine imaging procedures for detection of radioisotope tracer uptake in the patient body, using a variety of scanning modes supported by various acquisition types and imaging features designed to enhance image quality. The scanning modes include planar mode (Static, Multi-gated, Dynamic and Whole body scanning) and tomographic mode (SPECT, Gated SPECT, Whole body SPECT). The acquisition types include single and multi-isotope/ multi peak framellist mode single-photon imaging-enhancement features include, gating by physiological signals, and real-time automatic body contouring.
· CT System: Cross sectional images ofthe body by computer reconstruction of X-Ray transmission data taken at different angles and planes, including Axial, Cine, Helical, Cardiac, and Gated acquisitions. These images may be obtained with or without contrast. The CT system is indicated for head, whole body, cardiac and vascular X-Ray Computed Tomography applications.
· NM + CT System: Combined, hybrid SPECT and CT protocols, for CT-based SPECT attenuation corrected imaging as well as functional and anatomical mapping imaging (localization, registration and fusion).
The GE Discovery NM/CT 670 CZT system may include signal analysis and display equipment, patient and equipment supports, components and accessories. The system may include data and image processing to produce images in a variety of trans-axial and reformatted planes. The images can also be post processed to obtain additional imaging planes, analysis results and uptake quantitation. The system may be used for patients of all ages.
Discovery NM/CT 670 CZT is a SPECT-CT system consisting of two back-to-back gantries (i.e. an NM Gantry carrying 2 nuclear detectors and a CT Gantry), patient table, power distribution unit (PDU), operator console with two acquisition systems (i.e. NM and CT), interconnecting cables and associated accessories..
The system generates NM images, CT images and enables CTbased attenuation correction and anatomical localization of SPECT images. The NM images are generated through computer reconstruction of data acquired by a CZT-based dual detector NM system that uses a variety of planar and tomographic acquisition types. The CT images are generated by computer reconstruction of data acquired using a commercially available GE Optima CT 540 system.
Here's a breakdown of the acceptance criteria and study information for the GE Discovery NM/CT 670 CZT device, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly list quantitative acceptance criteria in a dedicated section. However, the study aims to demonstrate that the image quality and resolution of the GE Discovery NM/CT 670 CZT are at least equivalent to its predicate device (Discovery NM/CT 670). The reported performance is relative to the predicate device.
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| Clinical Image Quality & Resolution | Equivalent or superior to the predicate device. | Average overall image quality (IQ) and resolution of images from Discovery NM/CT 670 CZT were rated slightly higher than the images from the predicate device (Nal). |
| Reduced Acquisition Time/Dose Equivalence | Equivalent image quality/resolution with 75% of original counts. | Average overall image quality (IQ) and resolution results for Discovery NM/CT 670 CZT images created using 75% of the original counts (equivalent to 75% acquisition time or 75% lower injected dose) were found to be equivalent to the predicate device image produced with 100% of its counts. |
| Non-Clinical Performance | Successful verification and substantiation. | Successfully tested and showed compliance in: A) Energy resolution; B) Count rate linearity; C) Uniformity; D) System resolution; E) Lesion detectability (including a model observer study). |
2. Sample Size for the Test Set and Data Provenance
- Sample Size for Clinical Test Set: 19 subjects.
- Data Provenance: Retrospective, collected at one site in Israel.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
- Number of Experts: 2
- Qualifications of Experts: "Experienced and qualified Nuclear Medicine physicians." (Specific years of experience or subspecialty not detailed beyond "Nuclear Medicine physicians").
4. Adjudication Method for the Test Set
The document describes evaluations by "2 nuclear medicine physicians" using a 5-point Likert scale. It does not explicitly state an adjudication method (like 2+1 or 3+1). It implies that their ratings were averaged or directly compared, as it refers to "the average overall image quality" based on their evaluations. It's unclear if discordant readings were resolved.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- The study was a type of comparative effectiveness study in that it compared the new device (Discovery NM/CT 670 CZT) to a predicate device (Discovery NM/CT 670) by having human readers (nuclear medicine physicians) evaluate images.
- The study did not focus on the effect size of how much human readers improve with AI vs. without AI assistance. This study assessed the performance of a new imaging system (CZT-based detectors) compared to an older one (Nal-based detectors), not the impact of AI on human reading performance.
- Effect Size: "The average overall image quality (IQ, resolution) of the images from the Discovery NM/CT 670 CZT were rated slightly higher than the images from the Nal predicate device." This indicates a positive, albeit small, improvement detected by the human readers for the new system. Also, the new system achieved equivalent quality with 75% of the counts.
6. Standalone (Algorithm Only) Performance
- No standalone (algorithm only) performance study was explicitly described in the context of diagnostic interpretation.
- The document mentions a "model observer study" for lesion detectability as part of the non-clinical testing. This could be considered an "algorithm only" component for a specific task, but it's not presented as a comprehensive standalone diagnostic performance evaluation compared to the human readers' task. The clinical study specifically involved human physicians evaluating images.
7. Type of Ground Truth Used
- For the clinical study, the "ground truth" was expert consensus/evaluation (the ratings of the two Nuclear Medicine physicians on a 5-point Likert scale for image quality and resolution).
- The study's goal was to demonstrate equivalence/superiority in image quality as perceived by experts, not necessarily to diagnose specific diseases against a gold standard like pathology or long-term outcomes.
8. Sample Size for the Training Set
- The document does not provide information on a training set size. This submission is for a medical imaging system (hardware and associated software for image reconstruction), not a distinct AI/CADe/CADx algorithm that typically requires a separate training set.
- The system itself would have been developed and optimized based on extensive data, but this specific filing doesn't detail a separate "training set" in the context of an AI device. The testing described is for verification and validation of the system's performance.
9. How the Ground Truth for the Training Set Was Established
- As there's no explicitly mentioned "training set" for an AI algorithm in this context, there's no information on how its ground truth was established.
- The system's development would have involved various calibration and image quality targets, but these are distinct from the "ground truth" for training a diagnostic AI model.
§ 892.1200 Emission computed tomography system.
(a)
Identification. An emission computed tomography system is a device intended to detect the location and distribution of gamma ray- and positron-emitting radionuclides in the body and produce cross-sectional images through computer reconstruction of the data. This generic type of device may include signal analysis and display equipment, patient and equipment supports, radionuclide anatomical markers, component parts, and accessories.(b)
Classification. Class II.