(27 days)
The FibroScan® Family of Products (Models: 502 Touch, 530 Compact, and 430 Mini+) is intended to provide 50Hz shear wave speed measurements and estimates of tissue stiffness as well as 3.5 MHz ultrasound coefficient of attenuation (CAP: Controlled Attenuation Parameter) in internal structures of the body.
FibroScan® Family of Products (Models: 502 Touch, 530 Compact, and 430 Mini+) is indicated for noninvasive measurement in the liver of 50 Hz shear wave speed and estimates of stiffness as well as 3.5 MHz ultrasound coefficient of attenuation (CAP: Controlled Attenuation Parameter).
The shear wave speed and stiffness, and CAP may be used as an aid to diagnosis and monitoring of adult patients with liver disease, as part of an overall assessment of the liver.
Shear wave speed and stiffness may be used as an aid to clinical management of pediatric patients with liver disease.
FibroScan® system consists of a system unit and a hand-held probe. It is based on Vibration-Controlled Transient Elastography (VCTE™) technology, and is designed to perform non-invasive measurements of liver shear wave speed and estimates of tissue stiffness. The probe containing a mechanical vibrator produces low-amplitude elastic waves that travel through the skin and intercostal space into the liver. Ultrasound is used to track the shear (elastic) wave, measure its speed and provide estimated stiffness. The results are displayed on the system unit.
The focus of this submission is the addition of the S+ probe to models FibroScan® 530 Compact and FibroScan® 430 Mini+. The S+ probe addresses a smaller anatomic size of pediatric patients, while using the same principle of operation, intended use and methodology (i.e. application to patient, signal measurement, processing and display), design, materials, manufacturing and testing processes as the previously cleared M+ and XL+ probes. In addition, the S+ probe developed for the 530 Compact and 430 Mini+ models is similar to the S+ probe cleared for the FibroScan® 502 Touch model of the FibroScan® Family of Products.
Here's a summary of the acceptance criteria and the study information based on the provided document:
1. Table of Acceptance Criteria and Reported Device Performance:
The document doesn't explicitly state "acceptance criteria" for clinical performance. Instead, it discusses the performance characteristics of the FibroScan® S+ probe (for pediatric use) and compares them to previously cleared predicate devices. The performance data presented are for bias and precision using phantoms.
| Performance Characteristic | Acceptance Criteria (Implied by Predicate Performance) | Reported Device Performance (S+ probe on 530 Compact) | Reported Device Performance (S+ probe on 430 Mini+) | Reported Device Performance (S+ probe on 502 Touch - Predicate) |
|---|---|---|---|---|
| Bias (using CIRS phantoms E-1493-1 and E-1493-2) | Range of -13.5% to 3.6% (from predicate devices) | (-14.3%) - (3.6%) | (-13.7%) - (0.5%) | (-13.5%) - (3.6%) |
| Precision (using CIRS phantoms E-1493-1 and E-1493-2) | Range of 0.7% to 2.0% (from predicate devices) | (0.2%) - (1.9%) | (0.0%) - (1.6%) | (0.7%) - (2.0%) |
Note: The document explicitly states that the S+ probe underwent verification tests to ensure no new issues regarding safety and effectiveness and that software updates were verified through system tests. This implies that the performance in these verification tests (including bias and precision) met predefined standards aligned with the existing cleared devices.
2. Sample size used for the test set and the data provenance:
The document mentions that performance data for bias and precision were obtained using CIRS phantoms E-1493-1 and E-1493-2. This indicates that the "test set" for these specific performance metrics consisted of physical phantoms designed to mimic tissue properties, not human patient data.
- Sample size: Not applicable in the traditional sense for human subjects, as phantoms were used. The number of measurements taken on the phantoms is not specified.
- Data provenance: Not applicable as it involves phantom testing, not patient data from a specific country or collected retrospectively/prospectively.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of experts: Not applicable. The "ground truth" for phantom studies is typically established by the known physical properties of the phantoms themselves, as measured by calibrated reference methods or specified by the manufacturer (CIRS).
- Qualifications of experts: Not applicable.
4. Adjudication method for the test set:
- Adjudication method: Not applicable, as phantom testing does not involve human interpretation or adjudication in the way clinical studies do. The measurements are objective readings from the device on the phantom.
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:
- MRMC study: No, a multi-reader multi-case comparative effectiveness study was not explicitly mentioned or performed. This submission is for the addition of a new probe (S+ probe) to existing FibroScan models, focusing on engineering and performance characteristics using phantoms, rather than clinical efficacy studies involving human readers and AI. The device itself (FibroScan) is a measurement device, not an AI-assisted diagnostic tool that would typically involve human reader improvement with AI.
6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done:
- Standalone performance: The performance data presented (bias and precision) is inherent to the device's measurement capabilities on phantoms and can be considered "standalone" in that it reflects the device's accuracy and reproducibility without direct human interaction influencing the measurement itself (though a human operates the device). However, it's not "algorithm only" in the sense of a standalone AI diagnostic algorithm performing a task without human intervention, but rather the performance of the integrated mechanical and ultrasound system.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc):
- Type of ground truth: The ground truth for the bias and precision data was established by the known physical properties of the CIRS phantoms E-1493-1 and E-1493-2. These phantoms are designed to have specific, measurable shear wave speed and attenuation characteristics.
8. The sample size for the training set:
- Training set sample size: Not specified. This submission focuses on the verification of a new probe with existing systems, not on the development or training of a new algorithm. The document states that the S+ probe uses the "same principle of operation, intended use and methodology...design, materials, manufacturing and testing processes as the previously cleared M+ and XL+ probes." This implies that the underlying technology and any inherent "training" (calibration, algorithm development) would have occurred for the original device and probes, not this incremental modification.
9. How the ground truth for the training set was established:
- Ground truth for training set: Not specified in this document. Given that the submission is for an incremental change (adding an S+ probe to existing models) and leverages the "same principle of operation," the ground truth establishment for any initial algorithm development or calibration would have been part of earlier submissions for the predicate devices. It can be inferred that in the context of elastography devices, ground truth for initial development would typically involve comparisons to established reference methods (e.g., biopsy for liver stiffness, or known properties of tissue-mimicking phantoms).
§ 892.1560 Ultrasonic pulsed echo imaging system.
(a)
Identification. An ultrasonic pulsed echo imaging system is a device intended to project a pulsed sound beam into body tissue to determine the depth or location of the tissue interfaces and to measure the duration of an acoustic pulse from the transmitter to the tissue interface and back to the receiver. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II (special controls). A biopsy needle guide kit intended for use with an ultrasonic pulsed echo imaging system only is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.