(268 days)
- The Makoto Intravascular Imaging SystemTM is intended for the near-infrared examination of coronary arteries in patients undergoing invasive coronary angiography.
a. The System is intended for the detection of lipid-core-containing plaques of interest.
b. The System is intended for the assessment of coronary artery lipid core burden.
c. The System is intended for the identification of patients and plaques at increased risk of major adverse cardiac events. - The System is intended for ultrasound examination of coronary and peripheral intravascular pathology.
a. Intravascular ultrasound imaging is indicated in patients who are candidates for transluminal coronary and peripheral interventional procedures. The System is not indicated for use in the cerebral vessels.
The Makoto Intravascular Imaging System™ is an intravascular imaging device with the ability to simultaneously assess vessel composition and structure using near-infrared spectroscopy (NIRS) and intravascular ultrasound (IVUS). This dual-modality instrument performs near-infrared spectroscopic analysis of the vessel to detect lipid corecontaining plaques of interest (LCP) displayed in a map called a Chemogram, and simultaneously generates high resolution IVUS images that display structural details of the vessel and plaque in transverse and longitudinal views.
This FDA 510(k) summary describes the acceptance criteria and study results for the Makoto Intravascular Imaging System's new Automatic Border Contouring (ABC) and Guide Catheter Detection (GCD) software features.
Here's a breakdown of the requested information:
1. Table of Acceptance Criteria and Reported Device Performance
| Metric | Contour | Acceptance Criteria | ABC Performance Evaluation on Test Data | Result |
|---|---|---|---|---|
| Bland-Altman Plot Diameter Difference Limits of Agreement (95% CI) (mm) | Lumen | +/- 0.59 | [-0.37, 0.41] | PASS |
| Bland-Altman Plot Diameter Difference Limits of Agreement (95% CI) (mm) | EEM | +/- 0.74 | [-0.54, 0.52] | PASS |
| Bland-Altman Plot Area Difference Limits of Agreement (95% CI) (mm²) | Lumen | +/- 3.46 | [-2.3, 2.48] | PASS |
| Bland-Altman Plot Area Difference Limits of Agreement (95% CI) (mm²) | EEM | +/- 6.18 | [-4.5, 4.0] | PASS |
| Forward Hausdorff Distance 95% CI (mm) | Lumen | < 0.63 | [0.27, 0.29] | PASS |
| Forward Hausdorff Distance 95% CI (mm) | EEM | < 0.66 | [0.31, 0.35] | PASS |
| Reverse Hausdorff Distance 95% CI (mm) | Lumen | < 0.63 | [0.26, 0.28] | PASS |
| Reverse Hausdorff Distance 95% CI (mm) | EEM | < 0.66 | [0.29, 0.32] | PASS |
| Frame Level GCD Results | ||||
| Metric | Value | Acceptance Criteria | Result | |
| AUC | 0.98 | 0.9 | PASS | |
| Sensitivity | 0.86 | (Implicitly acceptable) | ||
| Specificity | 1.00 | (Implicitly acceptable) | ||
| Scan Level GCD Results | ||||
| Metric | Value | Acceptance Criteria | Result | |
| Total Individual Scan Level GCD Failures* | 2 | (Implicitly acceptable) | ||
| Sensitivity | 0.93 | 0.9 | PASS | |
| Specificity | 0.93 | 0.9 | PASS |
2. Sample Size and Data Provenance for the Test Set
- Sample Size:
- Patients: 18 unique patients
- Scans: 29 total scans
- Frames: 981 frames
- Data Provenance: Retrospective, collected from both Japanese hospitals (12 scans, 5 patients, 381 frames from 3 sites) and US hospitals (17 scans, 13 patients, 609 frames from 3 sites). The test dataset ensured no patient overlap with the calibration dataset.
3. Number of Experts and Qualifications for Ground Truth
- Number of Experts: 6 expert IVUS readers.
- Qualifications: Described as "expert IVUS readers." No specific years of experience or board certifications are mentioned in the provided text.
4. Adjudication Method for the Test Set
The document doesn't explicitly state an adjudication method (like 2+1 or 3+1 for discordance resolution among experts). It indicates that the reference standard was "established using six expert IVUS readers who served as ground truth annotators," and that "The annotation process was standardized through the use of IVUS Tracing Guidelines and a proprietary in-house developed tracing software to ensure consistency and reproducibility." This suggests a consensus-based approach guided by protocols, but the explicit steps for resolving disagreements are not detailed.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No, a MRMC comparative effectiveness study involving human readers with and without AI assistance was not detailed in this section. The acceptance criteria for ABC were established based on an inter- and intra-reader variability study using manual contouring by expert readers, which served as a benchmark for the algorithm's performance, but not a direct comparison of human performance improvement with AI.
6. Standalone (Algorithm Only) Performance
- Yes, the provided study presents the standalone performance of the ABC and GCD algorithms. The results in the tables directly evaluate the algorithms' accuracy against the established ground truth.
7. Type of Ground Truth Used
- Expert Consensus / Expert Annotation: The ground truth for the test set was established by "six expert IVUS readers" who followed "IVUS Tracing Guidelines" and used proprietary software to annotate specific features (guide catheter and stent regions, guidewire marking, lumen and EEM contours, calcium arcs, stent struts).
8. Sample Size for the Training Set
The document refers to a "calibration dataset" (which can be inferred to be the training/development set) but does not explicitly state the sample size for this set. It only mentions that the test dataset had "no patient overlap from the calibration dataset."
9. How Ground Truth for the Training Set Was Established
The document does not explicitly detail how the ground truth for the "calibration dataset" (training set) was established. It notes: "The test dataset was annotated by 6 readers, two of whom were not involved in the calibration dataset. While four annotators were shared between calibration and test datasets, the impact of this overlap was mitigated through randomized site allocation and diverse annotation styles to ensure the model did not learn specific annotator tendencies." This implies a similar expert annotation process was used for the calibration dataset as for the test set, but specific details are not provided.
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Image /page/0/Picture/0 description: The image shows the logo of the U.S. Food and Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is the FDA logo, which is a blue square with the letters "FDA" in white. To the right of the blue square is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue.
February 26, 2025
Infraredx, Inc. Stephen Sum Senior Vice President R&D, Clinical, Quality, and Regulatory 28 Crosby Drive Suite 100 Bedford, Massachusetts 01730
Re: K241576
Trade/Device Name: Makoto Intravascular Imaging System™ (TVC-MC10/TVC-MC10); Dualpro™ IVUS + NIRS Imaging Catheter (TVC-C195-42); Clarispro™ 014 Imaging Catheter (TVC-E195-42) Regulation Number: 21 CFR 870.1200, 21 CFR 892.1560, Regulation Name: Diagnostic Intravascular Catheter, Ultrasonic Pulsed Echo Imaging System, Regulatory Class: Class II Product Code: OBJ, OGZ, IYO Dated: January 27, 2025 Received: January 27, 2025
Dear Stephen Sum:
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 (OS) 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 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-reportingcombination-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-device-advicecomprehensive-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-device-safety/medical-device-reportingmdr-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/medicaldevices/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-device-advice-comprehensive-regulatory
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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,
MARCO CANNELLA -S
for
Aneesh Deoras Assistant Director Division of Cardiac Electrophysiology, Diagnostics, and Monitoring Devices Office of Cardiovascular Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known) K241576
Device Name
Makoto Intravascular Imaging System™ (TVC-MC10 / TVC-MC10i); Dualpro™ IVUS+NIRS Imaging Catheter (TVC-C195-42); Clarispro™ HD-IVUS Imaging Catheter (TVC-E195-42)
Indications for Use (Describe)
- The Makoto Intravascular Imaging SystemTM is intended for the near-infrared examination of coronary arteries in patients undergoing invasive coronary angiography.
a. The System is intended for the detection of lipid-core-containing plaques of interest.
b. The System is intended for the assessment of coronary artery lipid core burden.
c. The System is intended for the identification of patients and plaques at increased risk of major adverse cardiac events.
- The System is intended for ultrasound examination of coronary and peripheral intravascular pathology.
a. Intravascular ultrasound imaging is indicated in patients who are candidates for transluminal coronary and peripheral interventional procedures. The System is not indicated for use in the cerebral vessels.
| Type of Use (Select one or both, as applicable) |
|---|
| ------------------------------------------------- |
X Prescription Use (Part 21 CFR 801 Subpart D)
Over-The-Counter Use (21 CFR 801 Subpart C)
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510(k) Summary
02/03/2025
Infraredx, Inc.
781.345.9651
Dr. Stephen Sum
01730 USA
28 Crosby Drive Suite 100, Bedford, MA
Prepared On Contact Details
Applicant Name Applicant Address
Applicant Telephone Applicant Contact Applicant Contact Email
Device Name
Device Trade Name Makoto Intravascular Imaging System™ (TVC-MC10 / TVC-MC10i); Dualpro™ IVUS+NIRS Imaging Catheter (TVC-C195-42); Clarispro™ HD-IVUS Imaging Catheter (TVC-E195-42) Common Name Diagnostic intravascular catheter Ultrasonic Pulsed Echo Imaging System Classification Name Catheter, Intravascular, Plaque Morphology Evaluation Regulation Number 870.1200, 892.1560 Product Code(s) OGZ, IYO, OBJ
Legally Marketed Predicate Devices
| Predicate Number | Predicate Trade Name | Product Code |
|---|---|---|
| K213303 | TVC-E195-42, TVC-C195-42 & TVC-MC10/MC10i | OBJ, IYO, OGZ |
Device Description Summary
The Makoto Intravascular Imaging System™ is an intravascular imaging device with the ability to simultaneously assess vessel composition and structure using near-infrared spectroscopy (NIRS) and intravascular ultrasound (IVUS). This dual-modality instrument performs near-infrared spectroscopic analysis of the vessel to detect lipid corecontaining plaques of interest (LCP) displayed in a map called a Chemogram, and simultaneously generates high resolution IVUS images that display structural details of the vessel and plaque in transverse and longitudinal views.
Intended Use/Indications for Use
-
- The Makoto Intravascular Imaging System™ is intended for the near-infrared examination of coronary arteries in patients undergoing invasive coronary angiography.
- a. The System is intended for the detection of lipid-core-containing plaques of interest.
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- b. The System is intended for the assessment of coronary artery lipid core burden.
- c. The System is intended for the identification of patients and plaques at increased risk of major adverse cardiac events.
-
- The System is intended for ultrasound examination of coronary and peripheral intravascular pathology.
- a. Intravascular ultrasound imaging is indicated in patients who are candidates for transluminal coronary and peripheral interventional procedures. The System is not indicated for use in the cerebral vessels.
Indications for Use Comparison
The indications for use are the same.
Technological Comparison
The subject of this premarket notification is the addition of two software features on the Makoto Imaging System. These features are Automatic Border Contouring (referred to herein as ABC) and Guide Catheter Detection (referred to herein as GCD). The ABC software will assist physicians by automatically identifying the borders of the lumen and external elastic membrane (EEM) within the vasculature. The GCD software will assist physicians by automatically detecting the guide catheter edge during imaging procedures.
The proposed device has the same scientific principles of operation, principal technological characteristics, and safety profile as the currently marketed predicate device (K213303). Only minor design changes to the predicate device have been implemented. The tables below compare the general, catheter, controller, and console characteristics of the proposed and predicate devices.
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| General Characteristics | |||
|---|---|---|---|
| Characteristic | PROPOSED DEVICEInfraredxTVC-E195-42, TVC-C195-42 & TVC-MC10/MC10i | PREDICATE DEVICEInfraredxTVC-E195-42, TVC-C195-42 & TVC-MC10/MC10i(K213303) | Comparison withPredicate Device |
| Product Function | Near Infrared and Ultrasound Imaging System | Near Infrared and Ultrasound ImagingSystem | Same |
| Intended Use | The Makoto Intravascular Imaging System™ isintended for the near-infrared examination ofcoronary arteries in patients undergoinginvasive coronary angiography. The System isintended for the detection of lipid-core-containing plaques of interest. The System isintended for the assessment of coronary arterylipid core burden. The System is intended forthe identification of patients and plaques atincreased risk of major adverse cardiac events.The System is intended for ultrasoundexamination of coronary and peripheralintravascular pathology. Intravascularultrasound imaging is indicated in patients whoare candidates for transluminal coronary andperipheral interventional procedures. TheSystem is not indicated for use in the cerebralvessels. | The Makoto Intravascular Imaging System™ isintended for the near-infrared examination ofcoronary arteries in patients undergoinginvasive coronary angiography. The System isintended for the detection of lipid-core-containing plaques of interest. The System isintended for the assessment of coronaryartery lipid core burden. The System isintended for the identification of patients andplaques at increased risk of major adversecardiac events.The System is intended for ultrasoundexamination of coronary intravascularpathology. Intravascular ultrasound imagingis indicated in patients who are candidatesfor transluminal coronary interventionalprocedures. | Same |
| Where Used | Coronary and Peripheral | Coronary and Peripheral | Same |
| System Components | NIR/IVUS CatheterPortable or Fixed Console (Laser, SBC, powersupply) and Controller | NIR/IVUS CatheterPortable or Fixed Console (Laser, SBC,power supply) and Controller | Same |
| Classification | Catheter -Product Code OGZ, OBJ21 CFR 870.1200SystemProduct Code IYO21 CFR 892.1560 | Catheter -Product Code OGZ21 CFR 870.1200SystemProduct Code IYO21 CFR 892.1560 | Same |
| Catheter Characteristics | |||
| Characteristic | PROPOSED DEVICEInfraredxTVC-E195-42, TVC-C195-42 & TVC-MC10/ MC10i | PREDICATE DEVICEInfraredxTVC-E195-42, TVC-C195-42 &TVC-MC10/ MC10i (K213303) | Comparison with PredicateDevice |
| Usable Length | 160 cm | 160 cm | Same |
| Sheath Distal Tip Profile | 2.4 F | 2.4 F | Same |
| Guidewire rail length | 1.2 cm | 1.2 cm | Same |
| Imaging window profile | 3.2 F | 3.2 F | Same |
| Imaging core pullback | 15 cm | 15 cm | Same |
| Number of RO Marker Bands | 1 RO marker(0.5cm from distal tip) | 1 RO marker(0.5cm from distal tip) | Same |
| Maximum guidewire OD | 0.014 in. | 0.014 in. | Same |
| Minimum guide catheter I.D. | 6 F | 6 F | Same |
| Method of Sterilization | EtO | EtO | Same |
| Materials supplied in sterile packaging | Intravascular NIR/IVUS catheterPriming accessoryController sterile barrier | Intravascular NIR/IVUS catheterPriming accessoryController sterile barrier | Same |
| Shelf Life | 36 months | 36 months | Same |
| Transducer Center Frequency | 50MHz | 50MHz | Same |
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| Controller and Console Characteristics | |||
|---|---|---|---|
| Characteristic | PROPOSED DEVICEInfraredxTVC-E195-42, TVC-C195-42 and TVC-MC10/ MC10i | PREDICATE DEVICEInfraredxTVC-E195-42, TVC-C195-42 and TVC-MC10/ MC10i(K213303) | Comparison with PredicateDevice |
| Imaging Mode | Near Infrared light, Ultrasound | Near Infrared light, Ultrasound | Same |
| Output | NIR lightRF Ultrasound | NIR lightRF Ultrasound | Same |
| Hardware Components | CPU with 16GB RAM1 Monitor and 1 Touchscreen MonitorSwept Source Laser | CPU with 16GB RAM1 Monitor and 1 Touchscreen MonitorSwept Source Laser | Same |
| Laser Type | Swept Source Semiconductor Laser | Swept Source Semiconductor Laser | Same |
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| Imaging elementpullback speed | 0.5, 1.0, and 2.0 mm/s | 0.5, 1.0, and 2.0 mm/s | Same |
|---|---|---|---|
| Pullback Distance | 150mm | 150mm | Same |
| Controller Housing | Handle | Handle | Same |
| Controller RFID | Enabled for catheter type identification | Enabled for catheter type identification | Same |
| Controller User Interface | LCD screen | LCD screen | Same |
| Graphical User Interface | NIRS-IVUS image for coronary scanning(TVC-C195-42)IVUS image only for peripheral scanning(TVC-E195-42) | NIRS-IVUS image for coronary scanning(TVC-C195-42)IVUS image only for peripheral scanning(TVC-E195-42) | Same |
| Contouring of lumen andEEM borders in IVUSimage | Automatic or manual contouring of vesselborders | Manual contouring of vessel borders | Substantially equivalent |
| Detection of guidecatheter edge | Automatic detection of guide catheter edgebased on IVUS | Automatic detection of guide catheteredge based on NIRS | Substantially equivalent |
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Non-Clinical and/or Clinical Tests Summary and Conclusions
Design verification and validation bench testing was conducted for the changes in scope of this premarket application. Animal and clinical testing were not performed.
The bench testing demonstrates that the proposed device is substantially equivalent to the predicate device.
The sterilization and shelf-life evaluations of the catheters reported in this premarket notification show that the sterilization process remains acceptable and that the proposed device maintains a 36-month shelf life, consistent with the predicate device.
The biocompatibility testing of the catheters was conducted for an external communicating device in circulating blood, with a limited contact duration of ≤ 24 hrs. The series of testing was conducted utilizing Good Laboratory Practice (GLP) following ISO 10993 and ASTM standards. Biocompatibility testing was performed for cytoxicity, sensitization, irritation/intracutaneous reactivity, acute systemic toxicity, material mediated pyrogenicity, and hemocompatibility. All tests met the pre-determined acceptance criteria, as specified in the test protocols and associated test standards.
Minor hardware changes to accommodate the subject changes (ABC and GCD features) in the imaging console presented a potential impact on the electromagnetic interference (EMI) performance of the Makoto system. Testing of the system showed no significant increase in EMI.
Software verification and validation testing was also conducted for the subject changes included in this premarket application. The ABC and GCD testing successfully met all the criteria specified in the test protocol.
The following tables present the performance evaluation of ABC and GCD algorithms on blinded test data.
The ABC acceptance criteria were established based on an approved protocol and report which conducted an inter- and intra-reader variability study with three expert readers, 30 samples, and two trials. This study provided a benchmark for expected variability in manual contouring, ensuring that the algorithm's performance aligns with clinical practice standards.
Performance was assessed using error metrics, including diameter difference, area difference, and Hausdorff distance (HD) for lumen and EEM contours. For guide catheter detection, performance was evaluated based on detection accuracy, sensitivity, and specificity.
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| ABC Performance Evaluation Results on Test Data | ||||
|---|---|---|---|---|
| Performance Metric | Contour | Acceptance Criteria | ABC Performance Evaluation on Test Data | Result |
| Bland-Altman Plot Diameter Difference Limits of Agreement (95% CI) (mm) | Lumen | +/- 0.59 | [-0.37, 0.41] | PASS |
| Bland-Altman Plot Diameter Difference Limits of Agreement (95% CI) (mm) | EEM | +/- 0.74 | [-0.54, 0.52] | PASS |
| Bland-Altman Plot Area Difference Limits of Agreement (95% CI) (mm²) | Lumen | +/- 3.46 | [-2.3, 2.48] | PASS |
| Bland-Altman Plot Area Difference Limits of Agreement (95% CI) (mm²) | EEM | +/- 6.18 | [-4.5, 4.0] | PASS |
| Forward Hausdorff Distance 95% CI (mm) | Lumen | < 0.63 | [0.27, 0.29] | PASS |
| Forward Hausdorff Distance 95% CI (mm) | EEM | < 0.66 | [0.31, 0.35] | PASS |
| Reverse Hausdorff Distance 95% CI (mm) | Lumen | < 0.63 | [0.26, 0.28] | PASS |
| Reverse Hausdorff Distance 95% CI (mm) | EEM | < 0.66 | [0.29, 0.32] | PASS |
| Frame Level GCD Results | |||
|---|---|---|---|
| Metric | Value | Acceptance Criteria | Result |
| AUC | 0.98 | 0.9 | PASS |
| Sensitivity | 0.86 | ||
| Specificity | 1.00 |
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| Scan Level GCD Results | |||
|---|---|---|---|
| Metric | Value | Acceptance Criteria | Result |
| Total Individual ScanLevel GCD Failures* | 2 | ||
| Sensitivity | 0.93 | 0.9 | PASS |
| Specificity | 0.93 | 0.9 | PASS |
- False negatives and false positives
These results demonstrate that the subject device performs within clinically acceptable limits, as determined by inter-reader variability in manual contouring and predefined acceptance thresholds.
For scan level accuracy assessments, true positives were defined as results where a GC was correctly predicted within +/- 2 mm of the true location. True negatives were defined as results where no GC was predicted, when no GC was present according to ground truth. False positives were defined as scans where the predicted GC location was outside of the +/- 2 mm window of the true GC location, or when no GC was present according to the ground truth. False negatives were defined as scans where no GC location was predicted, while the truth showed a GC. Scans containing less than 2 mm of total GC length were defined as negatives for ground truth.
The following table provides a detailed breakdown of the test dataset, including the number of unique patients, frames, and scans. The test dataset consists of 18 unique patients, ensuring that the algorithm is evaluated on an independent dataset with no patient overlap from the calibration dataset. Among the 18 patients, 29 total scans were used for testing, with 12 of these from Japanese hospitals (5 patients across 3 sites), and 17 from US hospitals (13 patients across 3 sites). At the frame level, there were 381 frames included from Japanese hospitals and 609 frames included from US hospitals.
To ensure that the test dataset encapsulates clinically relevant disease states, patients are characterized based on the presence of calcium and stent struts, both of which are key indicators of disease severity. Calcium presence affects EEM contouring accuracy due to shadowing artifacts, while the presence of stent struts introduces additional challenges in seqmentation. The test dataset also includes patient cases with quidewire and side branches, further ensuring that real-world imaging complexities are represented.
| Test Data Summary and Characteristics | |||||||
|---|---|---|---|---|---|---|---|
| DataGroup | Frames | Patients | Scans | % CalciumPresence* | % GuidewirePresence* | % SideBranchPresence* | % StentStrutPresence* |
| Test | 981 | 18 | 29 | 38.9% | 96.6% | 9.2% | 20.7% |
- These percentages refer to % of frames
The fixed acquisition parameters of the Makoto Intravascular Imaging System™ are intrinsic to the Dualpro/Clarispro 014 IVUS transducer and TVC-M10/MC10i imaging system, and are not user-modifiable.
- Penetration Depth: The system offers a penetration depth of approximately . Page 8 of 10 K241576
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8 mm, corresponding to a 16 mm maximum field of view. This depth is preset to ensure optimal visualization of vascular structures. Notably, penetration depth is inversely related to ultrasound frequency.
- Focus: The focusing characteristics of the ultrasound beam are determined . by the transducer's intrinsic properties. Key parameters include:
- Focal Length: This is the distance from the transducer to the point . where the ultrasound beam is most narrowly focused, optimizing lateral resolution. The focal length is influenced by the transducer's diameter and the ultrasound frequency.
- . Focal Point Diameter: This refers to the beam's width at its narrowest point. Larger transducer diameters and higher frequencies result in a reduced focal point diameter.
- Frequency: The transducer operates at a nominal frequency of 50 MHz, with ● a variation range between 48 MHz and 53 MHz.
- Operation Mode: The Makoto imaging system (TVC-MC10/MC10i) operates . in B-mode, presenting images in a Cartesian coordinate system with fixed number of pixels along both the X and Y axes. These settings are preconfigured and cannot be modified by the user.
The reference standard for the testing dataset was established using six expert IVUS readers who served as ground truth annotators. The annotation process was standardized through the use of IVUS Tracing Guidelines and a proprietary in-house developed tracing software to ensure consistency and reproducibility. Annotators followed specific instructions for contour and structure identification, including:
- . Guide catheter and stent regions: Identification of relevant structures.
- . Guidewire marking: Placement of marking points at the brightest point or closest GW position.
- Lumen and EEM contours: Marking points used to delineate the lumen and EEM . boundaries.
- Calcium arcs: Placement of marks on the luminal edge of each calcified feature.
- Stent struts: Marking the center of each identifiable stent strut.
The test dataset was annotated by 6 expert readers, two of whom did not participate in annotating the calibration dataset. While four annotators were shared between calibration and test datasets, the impact of this overlap was mitigated through randomized site allocation and diverse annotation styles to ensure the model did not learn specific annotator tendencies.
The differences in the truthing process between calibration and test datasets were designed to reduce potential bias and ensure an independent performance evaluation. Although some annotators and sites overlapped, there was no patient overlap, and the diverse set of readers provided variability in annotation styles, preventing the model from overfitting to a single annotation methodology.
Several steps were taken to ensure that the test dataset remained independent from the training dataset, preventing data leakage and enabling an unbiased evaluation of model
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performance.
First, there was no patient overlap between the calibration and test datasets, ensuring that the model was assessed on previously unseen patient cases. This prevented the algorithm from memorizing specific anatomical features or imaging patterns from training patients, reinforcing its generalizability.
Second, the test dataset was collected from 6 clinical sites. While 3 of these test sites overlapped with calibration sites, half of the test sites were entirely new, ensuring that the model encountered imaging conditions not previously seen during training. This approach helped validate the model's ability to generalize across different imaging environments.
Third, a diverse set of annotators was used in both the calibration and test datasets to introduce variability in annotation behaviors. The test dataset was annotated by 6 readers, two of whom were not involved in the calibration dataset. This diversity ensured that the model was not exposed to a single annotation style, allowing it to generalize across different annotation behaviors commonly seen in clinical practice.
Additionally, annotators were randomly assigned data from different sites, preventing systematic biases related to site-specific annotation tendencies. The inclusion of multiple annotators with varied annotation styles further ensured that the truthing process for the test dataset remained independent of model development, preventing annotation bias from influencing test results.
Finally, the test dataset was blinded, meaning the algorithm developers had no exposure to the test patient cases during training or tuning (and the annotators had no exposure to the algorithm). This ensured that model evaluation reflected real-world clinical performance rather than learned biases from prior exposure. These measures collectively ensured that the test dataset provided an independent, unbiased assessment of model performance, supporting regulatory requirements for substantial equivalence.
§ 870.1200 Diagnostic intravascular catheter.
(a)
Identification. An intravascular diagnostic catheter is a device used to record intracardiac pressures, to sample blood, and to introduce substances into the heart and vessels. Included in this generic device are right-heart catheters, left-heart catheters, and angiographic catheters, among others.(b)
Classification. Class II (performance standards).