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The FibroScan® 630 is intended to provide shear wave speed measurements and estimates of tissue stiffness as well as ultrasound coefficient of attenuation (CAP: Controlled Attenuation Parameter) in internal structures of the body. The Shear wave speed and stiffness measurements may be used as an aid to clinical management of adult patients with liver disease.

FibroScan® 630 is indicated for non-invasive measurement in the liver of 50 Hz shear wave speed and estimates of stiffness as well as determining a 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 in the clinical management of pediatric patients with liver disease.

FibroScan® 630 (Expert) is also indicated for noninvasive measurement in the spleen of 100 Hz shear wave speed and estimates of stiffness that may be used as an aid to diagnosis, monitoring and clinical management of adult patients with liver disease, as part of an overall assessment of the liver.

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/spleen 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/spleen. 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 new FibroScan® 630, available in two configurations: FibroScan® 630 'Prime' (FS630P) and FibroScan® 630 'Expert' (FS630E). Both FS630P and FS630E include improvements of the FibroScan appearance and user interface.

The FS630P version has the same indications as the previously cleared models and is only indicated for non-invasive measurement of 50 Hz shear wave speed in the liver and estimates of its stiffness, as well as determination of a 3.5 MHz ultrasound coefficient of attenuation (CAP: Controlled Attenuation Parameter). The FS630E includes an expansion of the intended use to include noninvasive measurement of shear wave speed at 100Hz in the spleen and estimates of its stiffness as well as an inclusion of a B-Mode ultrasound imaging system to help the user locate the liver or spleen.

Here's a breakdown of the acceptance criteria and the study details for the FibroScan® 630, based on the provided text:

Acceptance Criteria and Device Performance for FibroScan® 630

The acceptance criteria for the FibroScan® 630 are implicitly defined by its equivalence to the predicate device, FibroScan® 530 Compact, and the clinical support for its expanded indications. The reported device performance is presented as a comparison to the predicate devices.

1. Table of Acceptance Criteria and Reported Device Performance

Note: The document explicitly states that the FibroScan® 630 is considered "equivalent" to the predicate in terms of bias and precision. Therefore, the acceptance criteria are to perform comparably to the predicate device within a specified range, or to have a similar safety and effectiveness profile. Numerical acceptance criteria are given for the liver and spleen shear wave speed and CAP bias and precision, which must fall within a range similar to or better than the predicate devices.

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

• Bench Testing (Phantoms): The text mentions testing "same sample of phantoms" for direct comparison between the candidate and predicate systems. It does not provide a specific number for the sample size of phantoms, but implies a consistent set was used for comparative measurements.
• Clinical Study (Spleen Stiffness):
  • Sample Size: 260 patients with chronic liver disease.
  • Data Provenance: Prospective, multi-center study. No specific country of origin is mentioned, but the manufacturer is based in Paris, France.

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

• Bench Testing (Phantoms): The ground truth for shear wave speed and attenuation was established by using "calibrated phantoms with known elasticity and attenuation." This implies that the nominal values of these phantoms served as the ground truth. No human experts are involved in establishing this specific ground truth for the phantoms themselves.
• Clinical Study (Spleen Stiffness): The ground truth for the clinical study is based on indirect measures and comparisons (HVPG, other non-invasive tests, clinical diagnoses of chronic liver disease, cirrhosis status). While clinicians are involved in these assessments and patient management, the document does not specify a panel of experts used to establish a single ground truth for each patient's spleen stiffness directly for the purpose of the study. Instead, the study evaluates the device's measurements against established clinical reference points and other diagnostic tools already in use.

4. Adjudication Method for the Test Set

The document does not describe any explicit adjudication method (e.g., 2+1, 3+1) for establishing ground truth in either the bench testing or the clinical study.

• Bench Testing: Ground truth is inherent to the calibrated phantoms.
• Clinical Study: Performance is assessed by comparing device measurements against clinical markers and other diagnostic tests, not against a consensually agreed-upon "ground truth" derived from expert review of the device's output.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No MRMC comparative effectiveness study involving human readers with and without AI assistance was mentioned or conducted. The device performs automated measurements of shear wave speed and attenuation.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance)

Yes, standalone performance was done for the device through the bench testing on phantoms. The bias and precision values for shear wave speed and CAP were measured directly from the device's output without human interpretation influencing the measurement itself. The clinical study also assesses the device's measurements directly as an aid to clinical management.

7. Type of Ground Truth Used

• Bench Testing: Calibrated phantoms with known elasticity and attenuation properties.
• Clinical Study (Spleen Stiffness): Indirect clinical endpoints and comparisons:
  • Hepatic Venous Pressure Gradient (HVPG)
  • Other Noninvasive Tests (NITs)
  • Diagnosis of chronic liver disease (e.g., hepatitis C, hepatitis B, alcoholic liver disease)
  • Cirrhosis status (for reproducibility study)
  • Patient follow-up (implicitly, for "aid to diagnosis, monitoring and clinical management").

8. Sample Size for the Training Set

The document does not explicitly state the sample size for any training set. As this device primarily involves physical measurements (Vibration-Controlled Transient Elastography) rather than a machine learning algorithm trained on a large dataset of images or clinical outcomes, the concept of a "training set" in the context of AI development is not directly applicable or described here. The development and calibration would typically involve engineering and physics-based validations.

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

Given that a "training set" in the machine learning sense is not explicitly described, the method for establishing its ground truth is also not detailed. The device's fundamental principles are based on known physics of wave propagation and tissue elasticity, and its calibration and validation would rely on known physical properties of materials (e.g., phantoms).

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