Salix Coronary Plaque (V1.0.0) is a web-based, non-invasive software application that is intended to be used for viewing, post-processing, and analyzing cardiac computed tomography (CT) images acquired from a CT scanner in a Digital Imaging and Communications in Medicine (DICOM) Standard format.

This software provides cardiologists and radiologists with interactive tools that can be used for viewing and analyzing cardiac computed tomography (CT) data for quantification and characterization of coronary plaques (i.e. atherosclerosis), stenosis and to perform calcium scoring in non-contrast cardiac CT

Salix Coronary Plaque (V1.0.0) is intended to complement standard care as an adjunctive tool and is not intended as a replacement to a medical professional's comprehensive diagnostic decision-making process. The software's semi-automated features are intended for an adult population and should only be used by qualified medical professionals experienced in examining and evaluating cardiac CT images.

Users should be aware that certain views make use of interpolated data. These data are created by the software based on the original data set. Interpolated data may give the appearance of healthy tissue in situations where pathology that is near or smaller than the scanning resolution may be present.

Device Description

Salix Coronary Plaque (K251837) is a web-based software application, hosted on Amazon Web Services cloud computing services, delivered using a SaaS model. The software provides interactive, post-processing tools for trained radiologists or cardiologists for viewing, analyzing, and characterizing cardiac computed tomography (CT) image data obtained from a CT scanner. The physician-driven coronary analysis is used to review CT image data to prepare a standard coronary report that may include the presence and extent of physician-identified coronary plaques (i.e., atherosclerosis) and stenosis, and assessment of calcium score performed on a non-contrast cardiac CT scan. The Cardiac CT image data are physician-ordered and typically obtained from patients who underwent CCTA or CAC CT for evaluation of CAD or suspected CAD.

AI/ML Overview

Here's a detailed breakdown of the acceptance criteria and the study proving the device meets them, based on the provided FDA 510(k) Clearance Letter for Salix Coronary Plaque (V1.0.0):

Acceptance Criteria and Device Performance

Salix Coronary Plaque Output	Statistic	Reported Device Performance (Estimate [95% CI])	Acceptance Criteria	Result
Vessel Level Stenosis	Percentage within one CAD-RADS category	95.8% [94.1%, 97.3%]	90%	Pass
Total plaque	ICC3¹	0.96 [0.94, 0.98]	0.70	Pass
Calcified plaque	ICC3¹	0.96 [0.90, 0.99]	0.80	Pass
Noncalcified plaque	ICC3¹	0.91 [0.84, 0.95]	0.55	Pass
Low attenuating plaque	ICC3¹	0.61 [0.41, 0.93]	0.30	Pass
Calcium Scoring	Pearson Correlation	0.958 [0.947, 0.966]	0.90	Pass
Centerline Extraction	Overlap score	0.8604 [0.8445, 0.8750]	0.80	Pass
Vessel Labelling	F1 Score	0.8264 [0.8047, 0.8479]	0.70	Pass
Lumen Wall Segmentation	Dice Score	0.8996 [0.8938, 0.9055]	0.80	Pass
Vessel Wall Segmentation	Dice Score	0.9016 [0.8962, 0.9070]	0.80	Pass

¹ Intraclass correlation coefficient two-way mixed model ICC(3, 1) was used.

Study Details

1. A table of acceptance criteria and the reported device performance:
See table above.

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

Multi-reader Multi-case (MRMC) study for Plaque Volumes and CAD-RADS:
- Sample Size: 103 adult patients (58 women, 45 men; mean 61 ± 12 years, range 23–84).
- Data Provenance: Retrospective data from seven geographically diverse U.S. centers (Wisconsin, New York, Arizona, and Alabama). Self-reported race was 57% White, 22% Black or African American, 12% Asian, 2% American Indian/Alaska Native; 7% declined/unknown. 13% identified as Hispanic or Latino. Scans were acquired on contemporary 64-detector row or newer systems from Canon, GE, Philips, and Siemens, ensuring vendor diversity.
Standalone Performance Validation for ML-enabled Outputs (Calcium Scoring, Centerline Extraction, Vessel Labelling, Lumen and Vessel Wall Segmentation):
- Sample Size:
  - 302 non-contrast series for calcium scoring.
  - 107 contrast-enhanced series for centerline extraction, vessel labeling, and wall segmentation.
- Data Provenance: Sourced from multiple unique centers in the USA that did not contribute any data to the training datasets for any Salix Central algorithm. The validation dataset consisted of de-identified cardiac CT studies from seven (7) centers across four (4) US states. Included representation of multiple scanner manufacturers (Canon, GE, Philips, and Siemens) and disease severity based on calcium score and maximum stenosis (CAD-RADS classification) based on source clinical radiology reports.

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

For Plaque Volumes and CAD-RADS (MRMC study):
- Number of Experts: Multiple (implied, at least two initial experts plus one adjudicator).
- Qualifications: Independent Level III-qualified (or equivalent experience) experts.
For ML-enabled Outputs (Standalone Performance Validation):
- Number of Experts: Multiple (implied, by using "board certified cardiologists and radiologists").
- Qualifications: Board certified cardiologists and radiologists with SCCT Level III certification (or equivalent experience).

4. Adjudication method for the test set:

For Plaque Volumes and CAD-RADS (MRMC study): Discrepancies between the initial expert readers were resolved by a third independent adjudicator with Level III qualifications or equivalent experience. This is a "2+1" adjudication method.
For ML-enabled Outputs (Standalone Performance Validation): The ground truth was "independently established" by the experts from the source clinical image interpretation. The document does not specify an adjudication method for these specific tasks if there were multiple ground truth annotations.

5. 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:

Yes, an MRMC study was done.
The study was not designed to measure the improvement of human readers with AI vs without AI assistance (i.e., a comparative effectiveness study of reader performance with and without the device).
Instead, the MRMC study evaluated the performance of human readers using the Salix Coronary Plaque device compared to an expert ground truth. It states, "Eight U.S.-licensed radiologists and cardiologists... acted as SCP readers... They began with the device's standalone automated output and made any refinements they deemed necessary."
The conclusion states: "This data supports our claim that qualified clinicians with minimal SCP specific training can achieve SCCT expert-level performance with SCP without the support of a core laboratory or specialized technician pre-read." This implies that the device enables a standard clinical user to achieve expert-level performance, but it does not quantify 'effect size' of improvement over their performance without the device.

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

Yes, a standalone performance validation was done for "ML-enabled Salix Coronary Plaque outputs for calcium scoring, centerline extraction, vessel labelling, and lumen and vessel wall segmentation against reference ground truth." These results are presented in the "Reported Device Performance" table and were shown to meet or exceed acceptance criteria.
The MRMC study also started with the "device's standalone automated output," suggesting that the algorithm's initial automated output was part of the workflow, though readers could refine it.

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

Expert consensus/annotation:
- For the MRMC study (plaque volumes and CAD-RADS), ground truth was established by "Independent Level III-qualified (or equivalent experience) experts [who] produced vessel-wall and lumen segmentations and assigned CAD-RADS stenosis categories." Discrepancies were adjudicated by a third expert.
- For the standalone ML-enabled outputs, ground truth was established by "board certified cardiologists and radiologists with SCCT Level III certification (or equivalent experience) using manual annotation and segmentation tools."

8. The sample size for the training set:

The document states that the validation data was "sourced from multiple unique centers in the USA that did not contribute any data to the training datasets for any Salix Central algorithm."
However, the actual sample size used for the training set for Salix Coronary Plaque (V1.0.0) is not provided in the given text.

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

This information is not provided in the given text for the Salix Coronary Plaque device. While it mentions how ground truth for the test set was established, it does not detail the process for the training data (nor the training data size).

Summary

FDA 510(k) Clearance Letter - Salix Coronary Plaque (V1.0.0)

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U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov

Doc ID # 04017.08.00

August 20, 2025

Artrya Limited
Gabriela Quijada
Quality and Regulatory Manager
1257 Hay Street
West Perth
Perth, WA 6005
Australia

Re: K251837
Trade/Device Name: Salix Coronary Plaque (V1.0.0)
Regulation Number: 21 CFR 892.2050
Regulation Name: Medical Image Management And Processing System
Regulatory Class: Class II
Product Code: QIH
Dated: June 16, 2025
Received: June 16, 2025

Dear Gabriela Quijada:

We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

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Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).

Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting (reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.

All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-

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K251837 - Gabriela Quijada Page 3

assistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely,

Jessica Lamb
Assistant Director, Imaging Software Team
DHT8B: Division of Radiologic Imaging
Devices and Electronic Products
OHT8: Office of Radiological Health
Office of Product Evaluation and Quality
Center for Devices and Radiological Health

Enclosure

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FORM FDA 3881 (6/20) Page 1 of 1 PSC Publishing Services (301) 443-6740 EF

DEPARTMENT OF HEALTH AND HUMAN SERVICES
Food and Drug Administration

Indications for Use

Form Approved: OMB No. 0910-0120
Expiration Date: 06/30/2023
See PRA Statement below.

510(k) Number (if known): K251837

Device Name: Salix Coronary Plaque (V1.0.0)

Indications for Use (Describe)

Type of Use (Select one or both, as applicable)
☒ Prescription Use (Part 21 CFR 801 Subpart D) ☐ Over-The-Counter Use (21 CFR 801 Subpart C)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

This section applies only to requirements of the Paperwork Reduction Act of 1995.
DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.

The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:

Department of Health and Human Services
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PRAStaff@fda.hhs.gov

"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."

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K251837

510(k) Summary

This summary of 510(k) safety and effectiveness information is submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.

Date Prepared: June 15, 2025

Submitter: Artrya Ltd.

Official Contact: Gabriela Quijada
1257 Hay Street
West Perth, 6005, Australia
Phone: +61 405 653 605

Secondary Contacts: Richard M. Stewart, Ph.D.
1230 Rosecrans Ave, Suite 300, PMB 713
Manhattan Beach, CA 90266
Phone: +1 415-735-4165

Proprietary Name: Salix Coronary Plaque (V1.0.0)

Common Name: Automated Radiological Image Processing Software System, Image Processing, Radiological

Classification: Class II Medical Device

Regulation Number: 21 CFR 892.2050

Product Codes: QIH, LLZ

Predicate Devices: CaRi-Plaque (K242240) - Primary
Salix Central (K243038) - Secondary

Reason For Submission: New Traditional 510(k)

Indications for Use

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Device Description

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Substantial Equivalence Discussion

Salix Coronary Plaque (SCP) is substantially equivalent to the primary and secondary predicates CaRi-Plaque (K242240) and Salix Central (K241038), respectively. The primary and secondary predicates are differentiated by study analysis and calcium scoring tools, which are reflected in the subject device. Both subject and predicate devices have the same Intended Use/Indications for Use and are similar with respect to key features and performance characteristics as shown in the Predicate Device Comparison Table below:

Predicate Device Comparison

Topic	Proposed Device	Primary Predicate Device	Secondary Predicate Device
Manufacturer	Artrya Ltd.	Caristo	Artrya Ltd.
Model Name	Salix Coronary Plaque (V1.0.0)	CaRi-Plaque	Salix Central
510(k) Number	Subject Device: K251837	K242240	K243038
Intended Use / Indications for Use	Salix Coronary Plaque (V1.0.0) is a web-based, non-invasive software application that is intended to be used for viewing, post-processing, and analyzing cardiac computed tomography (CT) images acquired from a CT scanner in a Digital Imaging and Communications in Medicine (DICOM) Standard format.This software provides cardiologists and radiologists with interactive tools that can be used for viewing and analyzing cardiac computed tomography (CT) data for quantification and characterization of coronary plaques (i.e. atherosclerosis), stenosis and to perform calcium scoring in non-contrast cardiac CTSalix Coronary Plaque (V1.0.0) is intended to complement standard care as an adjunctive tool and is not intended as a replacement to a medical professional's comprehensive diagnostic decision-making process. The software's semi-automated	CaRi-Plaque is intended to provide an optimized non-invasive application to analyze coronary anatomy and pathology and aid in determining treatment paths from a set of Computed Tomography (CT) Angiographic images.CaRi-Plaque is a web-based image processing application. It is a non-invasive diagnostic reading software intended for use as an interactive tool for viewing and analyzing cardiac CT data for determining the presence and extent of coronary plaques and luminal stenoses.CaRi-Plaque is intended for use by internal operators who have been appropriately trained in the software's functions, capabilities and limitations.Users should be aware	Salix Central is a web-based software application that is intended to be used for viewing, post-processing, and analyzing cardiac computed tomography (CT) images acquired from a CT scanner in a Digital Imaging and Communications in Medicine (DICOM) Standard format.This software provides tools that can be used for the qualitative and quantitative assessment of physician-identified coronary plaques and stenosis in coronary computed tomography angiography (CCTA) and to perform calcium scoring in non-contrast cardiac CT.Salix Central is intended to complement standard care as an adjunctive tool and is not intended as a replacement to a medical professional's comprehensive diagnostic decision-making process. The software's semi-

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Topic	Proposed Device	Primary Predicate Device	Secondary Predicate Device
Manufacturer	Artrya Ltd.	Caristo	Artrya Ltd.
Model Name	Salix Coronary Plaque (V1.0.0)	CaRi-Plaque	Salix Central
510(k) Number	Subject Device: K251837	K242240	K243038
	adult population and should only be used by qualified medical professionals experienced in examining and evaluating cardiac CT images.Users should be aware that certain views make use of interpolated data. These data are created by the software based on the original data set. Interpolated data may give the appearance of healthy tissue in situations where pathology that is near or smaller than the scanning resolution may be present.	that certain views make use of interpolated data. This is data that is created by the software based on the original data set. Interpolated data may give the appearance of healthy tissue in situations where pathology may be present that is near or smaller than the scanning resolution.The analysis results produced by the software and provided to the Healthcare Professional are not intended to replace the skill and judgment of a qualified medical practitioner. The analysis results should be reviewed with other clinical information which may include but is not limited to: The patient's original CT images, clinical history, symptoms, clinical risk factors, results of other diagnostic tests, and the clinical judgement of appropriately qualified Healthcare Professionals.	automated features are intended for an adult population and should only be used by qualified medical professionals experienced in examining and evaluating cardiac CT images.
Device Class	Class II	Class II	Class II
Product Code	LLZ, QIH	LLZ	QIH
Intended Users	Cardiologists, Radiologists and Clinical Specialists	Cardiologists and Radiologists	Cardiologists, Radiologists and Clinical Specialists
Operating Platform	Client-Server Google Chrome Application	Client-Side Google Chrome Application	Client-Server Google Chrome Application
Stand-alone Software	Yes	Yes	Yes

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Topic	Proposed Device	Primary Predicate Device	Secondary Predicate Device
Manufacturer	Artrya Ltd.	Caristo	Artrya Ltd.
Model Name	Salix Coronary Plaque (V1.0.0)	CaRi-Plaque	Salix Central
510(k) Number	Subject Device: K251837	K242240	K243038
DICOM Compliant	Yes; DICOM 3.0 or higher	DICOM 3	Yes; DICOM 3.0 or higher
Image Acquisition	CT	CT	CT
Secured Network Server Integration	Yes	Yes	Yes
Store Images	Yes	Yes	Yes
2D Imaging	Yes	Review of coronary vessels in 2D MPR, curved MPR, and straightened view.	Yes
2D Measurement	Similar	2D measurement tools of vessel diameter and contour	Similar
3D Imaging	Review of structures in 3D	Same	Same
Maximum Intensity Projection (MIP)	Yes; this visualization method not necessary for analyzing the presence and extent of coronary plaque and stenosis	N/A; this visualization method is not necessary for analyzing the presence and extent of coronary plaque and luminal stenosis	Yes
Multiplanar Reformat (MPR)	Yes, MPR with oblique slicing and variable slab thickness is not necessary analyzing the presence and extent of coronary plaque and luminal stenosis	MPR with oblique slicing and variable slab thickness is not necessary analyzing the presence and extent of coronary plaque and luminal stenosis	Yes
Study Analysis – Navigation Tools	PanningWindowingZoomingSeries, slices, and phases	SimilarPanningWindowingZoomingSeries, slices, and phases
Study Analysis – Visualization and Editing	CenterlineWallSignal Intensity Overlay	SimilarCenterlineWallSignal Intensity Overlay
Measurements	Distance & Area	Area	Distance & Area
Centerline Extraction and Wall Segmentation	Manual and semi-automatic / user-editable	Similar	Manual and semi-automatic / user-editable
Calcium Scoring	Yes	No	Yes
Reporting	Yes	Similar	Yes

Quantitative Measurements

| NCP volume: noncalcified plaque volume | Yes | Yes | Yes |

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Topic	Proposed Device	Primary Predicate Device	Secondary Predicate Device
Manufacturer	Artrya Ltd.	Caristo	Artrya Ltd.
Model Name	Salix Coronary Plaque (V1.0.0)	CaRi-Plaque	Salix Central
510(k) Number	Subject Device: K251837	K242240	K243038
CP volume: calcified plaque volume	Yes	Yes	Yes
LD-NCP volume: low-density noncalcified plaque volume	Yes	Yes	Yes
Total Plaque Volume	Yes	Yes	No
Vessel Volume	No. This is calculated but not reported as a device output.	No. This is calculated but not reported as a device output.	No
Total plaque burden: total plaque volume/analyzed vessel volume	Yes	Yes	No
NCP burden: noncalcified plaque volume/analyzed vessel volume	Yes	No	No
LD-NCP burden: low-density noncalcified plaque volume /analyzed vessel volume	Yes	No	No
CP burden: calcified plaque volume/analyzed vessel volume	Yes	No	No
Plaque composition Category (Noncalcified plaque, Calcified plaque, Mixed plaque)	Yes	No	No
QCAD: Maximal diameter stenosis, with respect to proximal and distal reference	Yes; Similar (categorical), Manual & Editable*	Yes, refers to a single reference	Yes; Similar, Manual & Editable
Area stenosis:	No; Calculated based on	Yes	No

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Topic	Proposed Device	Primary Predicate Device	Secondary Predicate Device
Manufacturer	Artrya Ltd.	Caristo	Artrya Ltd.
Model Name	Salix Coronary Plaque (V1.0.0)	CaRi-Plaque	Salix Central
510(k) Number	Subject Device: K251837	K242240	K243038
maximum area stenosis, with respect to proximal and distal references	diameter stenosis
Semi-Automated CAD RADS Stenosis: Maximal diameter stenosis, with respect to proximal and distal reference	Yes, Editable	No	No, Manual & Editable
Remodeling index: ratio of maximum vessel area/proximal and distal references	No, Presence/absence of positive remodeling as a classifier	Yes	No
Plaque length: diseased vessel length	No	Yes	No
Contrast density difference: maximum difference in contrast density over lesion with respect to proximal reference	No	Yes	No
MLD: minimal luminal diameter over lesion	No (categorized stenosis only into CAD RADS)	No. This is calculated but not reported as a device output.	No
Vessel profile: Area, maximum diameter, minimum diameter measured from selected vessel cross section	Yes, SimilarVessel Profile: maximum and minimum diameter measures from selected vessel cross sections	Yes	Yes, Similar

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Topic	Proposed Device	Primary Predicate Device	Secondary Predicate Device
Manufacturer	Artrya Ltd.	Caristo	Artrya Ltd.
Model Name	Salix Coronary Plaque (V1.0.0)	CaRi-Plaque	Salix Central
510(k) Number	Subject Device: K251837	K242240	K243038
Lumen profile: Area, maximum diameter, minimum diameter measured from selected lumen cross section	Yes, SimilarLumen Profile: maximum and minimum diameter measures from selected vessel cross sections	Yes	Yes, Similar
Vessel, plaque, and lumen segmentation	Yes. Semi-automatic with full option to manually edit with output demonstrated to meet pre-determined acceptance criteria in clinical performance study.	Yes. Semi-automatic (threshold-based segmentation with full option to edit); output demonstrated to meet pre-determined acceptance criteria in clinical performance study.	Deep learning based, vessel & lumen only; validated with ground truth by clinician expert readers, with full option to edit.

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Human Factors Engineering (HFE) Testing

HFE formative testing was conducted to verify usability and to identify previously unknown use-related hazards and use errors, as well as provide any additional critical knowledge needed for the safe and effective use of Salix Coronary Plaque in accordance with its intended use and performance claims.

Performance Testing

Performance testing was conducted to verify compliance with specified design requirements in accordance with FDA 21 CFR Part 820.30, IMDRF/SaMD WG/N12FINAL:2014, ISO 13485:2016, IEC 62304:2015, ISO 14971:2019 and NEMA 3.1-3.20 (2016) DICOM standards.

Verification and validation testing were conducted to ensure specifications and performance of the device and were performed per the FDA Guidance documents "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices" and "Content of Premarket Submission for Management of Cybersecurity in Medical Devices".

Salix Coronary Plaque has been tested according to the specifications that are documented in a master Software Verification and Validation Plan. Clinical Performance and Functional Performance testing are an integral part of Artrya's software product development process as described in the company's Quality Management System Policies and Procedures.

Clinical Validation Studies:

A retrospective, multi-reader multi-case design was used to compare SCP-generated plaque volumes and CAD-RADS™ stenosis grades with an expert ground-truth. The final dataset comprised cases from 103 adult patients (58 women, 45 men; mean 61 ± 12 years, range 23–84) imaged at seven geographically diverse U.S. centers (Wisconsin, New York, Arizona and Alabama).

Self-reported race was 57 % White, 22 % Black or African American, 12 % Asian and 2 % American Indian/Alaska Native; 7 % declined/unknown. 13% identified as Hispanic or Latino.

Scans were acquired on contemporary 64-detector row or newer systems from Canon, GE, Philips and Siemens, ensuring vendor diversity.

Independent Level III-qualified (or equivalent experience) experts produced vessel-wall and lumen segmentations and assigned CAD-RADS stenosis categories that served as the reference standard. Discrepancies between the expert readers was resolved by a third independent adjudicator with Level III qualifications or equivalent experience. SCP-derived ground truth metrics included total, calcified, non-calcified and low-attenuation plaque volumes.

Eight U.S.-licensed radiologists and cardiologists—each with 2 to 8 years of independent CCTA practice—acted as SCP readers, reflecting routine clinical users in a standard of care setting rather than expert core-lab analysts.

Before study initiation, readers completed one structured training session based on the device Instructions for Use and reviewed at least three sample cases. During the evaluation, each case was interpreted by three distinct SCP readers. They began with the device's standalone automated output and made any refinements they deemed necessary; no pre-editing by technicians or a core laboratory was allowed.

Additionally, performance validation testing was performed for the ML-enabled Salix Coronary Plaque outputs for calcium scoring, centerline extraction, vessel labelling, and lumen and vessel wall segmentation against reference ground truth established by board certified cardiologists and radiologists with SCCT Level III certification (or equivalent experience) using manual annotation and segmentation tools. In each case the reference was independently established from the source clinical image interpretation.

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Data for the validation was sourced from multiple unique centers in the USA that did not contribute any data to the training datasets for any Salix Central algorithm.

The validation dataset consisted of de-identified cardiac CT studies from seven (7) centers across four (4) US states. This consisted of 302 non-contrast series for the testing of calcium scoring, 107 contrast-enhanced series for the testing of centerline extraction, vessel labelling, and wall segmentation. Each validation test included representation of multiple scanner manufacturers (i.e., Canon, GE, Philips, and Siemens) and disease severity based on calcium score and maximum stenosis (CAD-RADS classification) based on the source clinical radiology reports.

Salix Coronary Plaque performance exceeded all the pre-defined acceptance criteria for all validation tests.

Salix Coronary Plaque Output	Statistic	Estimate [95% CI]	Acceptance Criteria	Result
Vessel Level Stenosis	Percentage within one CAD-RADS category	95.8% [94.1%, 97.3%]	90%	Pass
Total plaque	ICC3¹	0.96 [0.94, 0.98]	0.70	Pass
Calcified plaque	ICC3¹	0.96 [0.90, 0.99]	0.80	Pass
Noncalcified plaque	ICC3¹	0.91 [0.84, 0.95]	0.55	Pass
Low attenuating plaque	ICC3¹	0.61 [0.41, 0.93]	0.30	Pass
Calcium Scoring	Pearson Correlation	0.958 [0.947, 0.966]	0.90	Pass
Centerline Extraction	Overlap score	0.8604 [0.8445, 0.8750]	0.80	Pass
Vessel Labelling	F1 Score	0.8264 [0.8047, 0.8479]	0.70	Pass
Lumen Wall Segmentation	Dice Score	0.8996 [0.8938, 0.9055]	0.80	Pass
Vessel Wall Segmentation	Dice Score	0.9016 [0.8962, 0.9070]	0.80	Pass

¹ Intraclass correlation coefficient two-way mixed model ICC(3, 1) was used.

This data supports our claim that qualified clinicians with minimal SCP specific training can achieve SCCT expert-level performance with SCP without the support of a core laboratory or specialized technician pre-read.

Conclusion

The comprehensive performance testing and comparison to primary and secondary predicates CaRi-Plaque (K242240) and Salix Central (K243038), respectively, supports that Salix Coronary Plaque (K251837) is substantially equivalent to the named predicate devices. The device has the same intended use as the predicate devices and minor differences in expanded indications compared to the predicates that do not affect its safety and effectiveness. Minor differences in technological characteristics between the devices do not raise unique questions of safety or effectiveness, which have been addressed in accordance with Artrya's Quality Management System.

Regulation Number and Section

§ 892.2050 Medical image management and processing system.

(a)
Identification. A medical image management and processing system is a device that provides one or more capabilities relating to the review and digital processing of medical images for the purposes of interpretation by a trained practitioner of disease detection, diagnosis, or patient management. The software components may provide advanced or complex image processing functions for image manipulation, enhancement, or quantification that are intended for use in the interpretation and analysis of medical images. Advanced image manipulation functions may include image segmentation, multimodality image registration, or 3D visualization. Complex quantitative functions may include semi-automated measurements or time-series measurements.(b)
Classification. Class II (special controls; voluntary standards—Digital Imaging and Communications in Medicine (DICOM) Std., Joint Photographic Experts Group (JPEG) Std., Society of Motion Picture and Television Engineers (SMPTE) Test Pattern).