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ECG-less Cardiac streamlines patient preparation by enabling an alternative acquisition of cardiac CT images for general cardiac assessment without the need of a patient-attached ECG monitor. ECG-less Cardiac is for adults only.

ECG-less Cardiac is a software device that is an additional, optional cardiac scan mode that can be used on the Revolution Apex Elite, Revolution Apex, and Revolution CT with Apex edition systems. There is no change to the predicate device hardware to support the subject device. Currently, the available cardiac scan modes on the Revolution CT Family are Cardiac Axial and Cardiac Helical, which makes use of an ECG signal to physiologically trigger the cardiac acquisitions and/or to retrospectively gate the reconstruction.

ECG-less Cardiac is a third cardiac scan mode that introduces the ability to acquire cardiac images without the need of a patient-attached ECG monitor. Hence, an ECG signal from the patient is not utilized for this scan mode. The ECG-less Cardiac workflow leverages the full-heart coverage capability of 160 mm configurations, fast gantry speeds (0.28 and 0.23 s/rot), and existing cardiac software options of SmartPhase and SnapShot Freeze 2 (K183161) to acquire images that are suitable for coronary and cardiac functional assessment.

The ECG-less cardiac feature allows the user to acquire a cardiac CT scan without the need to complete the steps associated with utilizing an ECG monitor, such as attaching ECG electrodes to the patient, checking electrode impedance, and confirming an ECG trace is displayed on the operator console, thus optimizing the workflow.

ECG-less Cardiac may be best utilized in examinations where excluding the ECG connection would streamline the patient examination, including and unloading of the patient. This may result in an improved workflow for certain clinical presentations. ECG-less Cardiac may also increase access to cardiac assessment for patients that are difficult to receive an ECG signal from. Circumstances where the subject device is expected to increase cardiac access includes scenarios where trauma patient has a diagnostic ECG attached and/or other instrumentation, such that there is added difficulty of attaching ECG leads for a gated scan, and situations where it is challenging to get an ECG signal from a patient such as a patient's t-wave triggering the scan or R-peak being difficult to detect.

Here's a summary 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 implicitly derived from the study's conclusions, focusing on diagnostic utility and image quality. No specific quantitative thresholds for acceptance are explicitly stated in the document beyond "interpretable without a significant motion artifact penalty" and "of diagnostic utility."

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

• Sample Size for Test Set: The document does not explicitly state the exact number of cases or images included in the reader study (test set). It refers to "a reader study of sample clinical data" and "prospectively collected clinical data."
• Data Provenance: The data was prospectively collected clinical data from patients undergoing a routine cardiac exam. The country of origin is not specified.

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

• Number of Experts: Three experts were used.
• Qualifications of Experts: They were board-certified radiologists who specialize in cardiac imaging. The document does not specify their years of experience.

4. Adjudication Method for the Test Set

The adjudication method is not explicitly stated. The document mentions that each image was "read by three board certified radiologists who specialize in cardiac imaging who provided an assessment of image quality." This suggests independent readings, but it does not detail a consensus or adjudication process (e.g., 2+1, 3+1).

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance

• No, an MRMC comparative effectiveness study involving human readers improving with AI vs. without AI assistance was not conducted or reported.
• The study was a reader study where experts assessed images generated by the ECG-less Cardiac system. The primary goal was to validate the diagnostic utility and image quality of the ECG-less Cardiac acquisitions themselves, not to assess human reader performance with or without an AI assist feature.

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

Yes, a form of standalone performance was assessed in the engineering bench testing. This testing "assessed how simulated ECG-less Cardiac scan conditions performed against an ECG-gated 'ground truth' nominal phase location." This component evaluated the algorithm's ability to generate images comparable to traditional ECG-gated acquisitions without human interpretation being the primary focus.

7. The Type of Ground Truth Used

• For the engineering bench testing, the ground truth was an ECG-gated "ground truth" nominal phase location. This implies a comparison to a known, established reference standard for cardiac imaging synchronization.
• For the clinical reader study, the ground truth was effectively the expert consensus/assessment of the three board-certified radiologists regarding the interpretability, motion artifact, and diagnostic utility of the ECG-less images. There is no mention of pathology or outcomes data being used as ground truth for this part of the study.

8. The Sample Size for the Training Set

The document does not provide any information regarding the sample size used for the training set of the ECG-less Cardiac software.

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

The document does not provide any information on how the ground truth for the training set was established. It only discusses the testing (validation) phase.

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The system is intended to produce cross-sectional images of the body by computer reconstruction of x-ray transmission projection data from the same axial plane taken at different angles. The systems with 160 mm detector coverage have the capability to image whole organs in a single rotation. Whole organs include but are not limited to brain, heart, liver, kidney, pancreas, etc. The system may acquire data using Axial, Cardiac, and Gated CT scan techniques from patients of all ages. These images may be obtained either with or without contrast. This device may include signal analysis and display equipment, patient and equipment supports, components and accessories.

This device may include data and image processing to produce images in a variety of trans-axial and reformatted planes. Further, the images can be post processed to produce additional imaging planes or analysis results.

The system is indicated for head, whole body, cardiac, and vascular X-ray Computed Tomography applications.

The device output is a valuable medical tool for the diagnosis of disease, trauma, or abnormality and for planning, guiding, and monitoring therapy.

If the spectral imaging option is included on the system can acquire CT images using different kV levels of the same anatomical region of a patient in a single source. The differences in the energy dependence of the attenuation coefficient of the different materials provide information about the chemical composition of body materials. This approach enables images to be generated at energies selected from the available spectrum to visualize and analyze information about anatomical and pathological structures.

GSI provides information of the chemical composition of renal calculi by calculation and graphical display of the spectrum of effective atomic number. GSI Kidney stone characterization provides additional information to aid in the characterization of uric acid versus nonuric acid stones. It is intended to be used as an adjunct to current standard methods for evaluating stone etiology and composition.

The Revolution CT family of products, including Revolution CT, Revolution CT ES, Revolution CT with Apex edition, Revolution CT ES with Apex edition Apex, Revolution Apex Elite, Revolution Apex Plus, and Revolution Apex Select, Revolution CT Power, Revolution Apex Pro are multi-slice CT scanners consisting of a gantry, patient table, scanner desktop (operator console), system cabinet, power distribution unit (PDU), and interconnecting cables. The system includes image acquisition hardware, image acquisition and reconstruction software, and associated accessories.

GE has modified the cleared Revolution CT (K19177) within our design controls to include the 0.23 s/rot option. The 0.23s/rot option can be used with axial scan acquisitions and is especially beneficial during certain cardiac scan acquisitions. The scan workflow and user interface remain identical to the of the predicate device, with the exception that the user now has the option to select 0.23 s/rot in addition to other gantry rotation speeds.

The addition of a new maximum gantry rotation speed leads to updates to system performance claims about maximum temporal resolution when combined with the optional Snapshot Freeze 2 (K183161) feature.

The provided text does not contain detailed acceptance criteria for the device or a study explicitly proving the device meets said criteria. The document is a 510(k) premarket notification for a Computed Tomography (CT) system (Revolution CT family) that includes the addition of a 0.23 s/rot option. The focus of the submission is to demonstrate substantial equivalence to a predicate device (Revolution CT, K191777), not to present an independent study with explicit acceptance criteria for a novel device performance claim.

However, based on the information provided, we can infer some aspects related to evaluating the new 0.23 s/rot option:

Inferred Acceptance Criteria and Reported Device Performance (Focusing on the 0.23 s/rot option)

Detailed Breakdown of Study Information (Focusing on the 0.23 s/rot option):

1. Sample size used for the test set and the data provenance:

   • Test Set Sample Size: Not explicitly stated by number of cases or patients. The non-clinical testing involved "a cardiac phantom" and "mathematical modeling." This implies a phantom-based study for physical performance and computational analysis.
   • Data Provenance: The study was non-clinical and conducted by the manufacturer, GE Medical Systems, LLC. It's an internal validation of the new feature.

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

   • This information is not provided in a way that aligns with "ground truth" for a clinical test set, as no clinical study was performed. The evaluation relied on technical performance metrics validated against engineering standards and a cardiac phantom, rather than expert interpretation of medical images.

3. Adjudication method (e.g., 2+1, 3+1, none) for the test set:

   • Not applicable as there was no clinical test set requiring expert adjudication. The substantiation was based on physical measurements from a phantom and mathematical modeling.

4. 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 MRMC comparative effectiveness study was done. This submission is for a hardware/software update to a CT scanner, not an AI-assisted diagnostic tool.

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

   • The evaluation focused on the standalone performance of the CT system with the new gantry rotation speed. The "algorithm" here refers to the system's operational parameters and image reconstruction, rather than a diagnostic AI algorithm. The performance items were verified and substantiated through phantom studies and mathematical analysis.

6. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

   • For the non-clinical testing, the "ground truth" was likely established by:
     • Physical measurements/known properties of the cardiac phantom: For evaluating temporal resolution and other imaging characteristics.
     • Engineering specifications and mathematical models: To predict and verify performance parameters.

7. The sample size for the training set:

   • Not applicable in the context of this submission. The device is a CT scanner with a hardware and software update, not a machine learning algorithm that requires a specific "training set" of patient data in the typical sense. The development involved general engineering design, development, and verification processes.

8. How the ground truth for the training set was established:

   • Not applicable as there was no distinct "training set" for a machine learning model. The system's design and engineering would be based on established physics, engineering principles, and prior knowledge from existing CT technology, rather than a labeled training dataset.

Summary of the Study:

The study was a non-clinical performance evaluation conducted by GE Medical Systems, LLC. It involved:

• Engineering testing: To ensure compliance with electrical, mechanical, and safety standards (IEC 60601-1 Ed. 3.1, 21CFR Subchapter J, NEMA XR-25, XR-26, and XR-28).
• Performance evaluation testing: Utilized a cardiac phantom and mathematical modeling to technically substantiate claims related to the 0.23 s/rot option, particularly in conjunction with the Snapshot Freeze 2 feature for temporal resolution.
• Quality System Compliance: The development followed the Quality System Regulations of 21CFR 820 and ISO 13485, including risk analysis, technical reviews, design reviews, code inspections, and various levels of testing (unit, integration, performance, safety, simulated use).

The conclusion was that the device, with the new 0.23 s/rot option, is "as safe and effective, and performs in a substantially equivalent manner to the predicate device Revolution CT (K191777)." No clinical testing was deemed necessary because the modifications were fully testable on an engineering bench.

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