(25 days)
Cardius-1, Cardius-2, Cardius-3, Cardius 1 XPO, Cardius 3 XPO, Cardius 3 XPO Imaging Systems:
The Cardius product models are intended for use in the generation of cardiac studies, including planar and Single Photon Emission Computed Tomography (SPECT) studies, in nuclear medicine applications.
2020tc SPECT Imaging System:
The Digirad 2020tc SPECT Imaging system is intended for use in the generation of both planar and Single Photon Emission Computed Tomography (SPECT) clinical images in nuclear medicine applications. The Digirad SPECT Rotating Chair is used in conjunction with the Digirad 2020tc Imager™ to obtain SPECT images in patients who are seated in an upright position.
Specifically, the 2020tc Imager™ is intended to image the distribution of radionuclides in the body by means of a photon radiation detector. In so doing, the system produces images depicting the anatomical distribution of radioisotopes within the human body for interpretation by authorized medical personnel.
The proposed change involves an updated version of nSPEED™ (3D-OSEM) reconstruction software to process cardiac SPECT studies acquired with non-parallel hole collimators, using half time and/or half count densities. With the updated software, cardiac SPECT studies acquired with both parallel hole and non-parallel hole collimators, using half time and/or half count densities, can be processed.
Here's an analysis of the provided text to extract the acceptance criteria and study details:
1. Table of Acceptance Criteria and Reported Device Performance:
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Equivalent image quality between: |
- Previously cleared 2D-OSEM reconstruction (processing "preferred" time/count data)
- New nSPEED™ (3D-OSEM) reconstruction (processing half-time and/or half-count density data) | Digirad testing performed with cardiac phantom images and a multicenter evaluation with data from over 450 patient images showed equivalent image quality between the two processing methods. |
| Very good quantitative correlation between: - Previously cleared 2D-OSEM reconstruction (processing "preferred" time/count data)
- New nSPEED™ (3D-OSEM) reconstruction (processing half-time and/or half-count density data) | Digirad testing performed with cardiac phantom images and a multicenter evaluation with data from over 450 patient images showed very good quantitative correlation between the two processing methods. |
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size: Over 450 patient images
- Data Provenance: Multicenter evaluation; acquired with parallel hole and non-parallel hole collimators using Digirad imaging systems. The location of the centers (e.g., country of origin) is not specified. The study appears to be retrospective, as it uses "data from over 450 patient images acquired."
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts:
This information is not provided in the submitted text. The submission mentions "Digirad testing" and "multicenter evaluation" but does not detail how ground truth was established or if experts were involved in a formal capacity for image quality assessment or quantitative correlation.
4. Adjudication Method for the Test Set:
This information is not provided in the submitted text.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, and if so, what was the effect size of how much human readers improve with AI vs without AI assistance:
- No, an MRMC comparative effectiveness study was not explicitly done in the context of human readers improving with AI vs. without AI assistance.
- The study focuses on demonstrating the equivalence of a new reconstruction software (nSPEED™ 3D-OSEM) compared to an older one (2D-OSEM) for processing reduced dose/time cardiac SPECT data. It assesses image quality and quantitative correlation of the output images, not the performance of human readers with or without an AI assist. This is a technical performance study of image processing, not a clinical efficacy study with human readers as the primary endpoint.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, a standalone evaluation of the algorithm's output was done. The study's conclusion is that the new nSPEED™ software "produce[s] equivalent image quality and very good quantitative correlation" when compared to the previously cleared 2D-OSEM technique. This assessment of image quality and quantitative correlation is an evaluation of the algorithm's output in a standalone manner.
7. The Type of Ground Truth Used:
- The ground truth reference appears to be the images processed with the previously cleared 2D-OSEM reconstruction technique using "preferred" time and/or count data. The new software's output is compared to this established and cleared method. This could be considered a form of clinical consensus or established practice as defined by the "ASNC 2008 Imaging Guidelines." It is not directly pathology or outcomes data.
8. The Sample Size for the Training Set:
The text does not provide any information regarding a training set size. This indicates that the software update was likely evaluated for its performance characteristics on clinical data rather than being a de novo AI model that required a separate training phase to learn a specific task. Reconstruction algorithms are typically developed and then validated.
9. How the Ground Truth for the Training Set Was Established:
As no training set is mentioned or implied for this specific submission, there is no information on how its ground truth might have been established.
§ 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.