(28 days)
The ACUSON Redwood ultrasound imaging system is intended to provide images of, or signals from, inside the body by an appropriately trained healthcare professional in a clinical setting for the following applications: Fetal, Abdominal, Pediatric, Small Parts, OB/GYN (useful for visualization of the ovaries, follicles, uterus, and other pelvic structures), Adult, Pediatric and Neonatal Cardiac, Pelvic, Neonatal Cephalic, Adult Cephalic, Vascular, Musculoskeletal, Superficial Musculoskeletal, Transcranial, and Peripheral Vascular.
The system supports the Ultrasound-Derived Fat Fraction (UDFF) measurement tool to report an index that can be useful as an aid to a physician managing adult patients with hepatic steatosis.
The system also provides the ability to measure anatomical structures: fetal, abdominal, pediatric, small organ, neonatal cephalic, adult cephalic, cardiac (adult, pediatric and neonatal), transesophageal, transrectal, transvaginal, peripheral vessel, musculoskeletal (conventional), musculoskeletal (superficial), and calculation packages that provide information to the clinician that may be used adjunctively with other medical data obtained by a physician for clinical diagnosis purposes.
The ACUSON Redwood Diagnostic Ultrasound System is multi-purpose, mobile, softwarecontrolled, diagnostic ultrasound system with an on-screen display for thermal and mechanical indices related to potential bio-effect mechanisms. Its function is to acquire harmonic ultrasound echo data and display it in B-Mode, M-Mode, Pulsed (PW) Doppler Mode, Continuous (CW) Doppler Mode, Color Doppler Mode, Color M mode, Doppler Tissue Image mode, Amplitude Doppler Mode, Combination modes, Harmonic Imaging and 3D Imaging modes, and 4D imaging modes on a flat panel display for diagnostic ultrasound imaging.
Here's an analysis of the acceptance criteria and the study proving the device meets them, based on the provided text:
Preamble: The provided document is a 510(k) summary for the ACUSON Redwood Diagnostic Ultrasound System. The core of the study described focuses on the new "Ultrasound-Derived Fat Fraction (UDFF)" feature. The general diagnostic ultrasound system itself is noted to use "the same technology and principles as existing predicate devices" and therefore "clinical studies were not required to support substantial equivalence" for its broader functionality. The following information pertains specifically to the UDFF feature.
Acceptance Criteria and Device Performance (UDFF Feature)
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Study 1: Correlation with Predicate Device (ACUSON Sequoia UDFF) | |
| Significance level p-Value 0.85.** (This meets the criterion for strong diagnostic accuracy.) |
Further Study Details for UDFF Feature:
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Sample Sizes Used for the Test Set and Data Provenance:
- Study 1: N = 30 subjects
- Ethnicity/Country: 15 from USA, 15 from Korea
- Sex: 15 Male, 15 Female
- Retrospective or Prospective: Not explicitly stated, but the description of "To verify the clinical reliability...To record the UDFF measurement acquisition time" suggests it was a prospective data collection for this study.
- Study 2: N = 28 subjects
- Ethnicity/Country: 28 from Korea
- Sex: 20 Male, 8 Female
- Retrospective or Prospective: Not explicitly stated, but given the objective "To verify that UDFF of ACUSON Redwood shows good agreement with MRI-PDFF" and "To verify the clinical accuracy...", it implies prospective data collection where both UDFF and MRI-PDFF were acquired for correlation.
- Study 1: N = 30 subjects
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Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
- Study 1: This study primarily focused on comparing the ACUSON Redwood UDFF to the ACUSON Sequoia UDFF and internal consistency (test-retest reliability). Ground truth, in the sense of a definitive diagnostic outcome, was not the primary endpoint that would require expert adjudication. The "ground truth" here is the measurement from the established predicate device (ACUSON Sequoia UDFF) and the consistency of the Redwood's own measurements.
- Study 2: The ground truth for this study was MRI-PDFF (Magnetic Resonance Imaging Proton Density Fat Fraction). This MRI-PDFF is considered a quantitative reference standard for liver fat quantification. The document does not specify the number of human readers/experts directly involved in establishing the MRI-PDFF values for the study, as MRI-PDFF is typically an objective, quantitative measurement derived from MRI sequences and software, rather than a subjective expert read needing adjudication.
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Adjudication Method for the Test Set:
- Not applicable as the ground truths (predicate device measurements and MRI-PDFF) are presented as objective measurements and not subjective expert interpretations requiring adjudication.
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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, an MRMC comparative effectiveness study involving human readers and AI assistance was not mentioned or performed for the UDFF feature as described. The UDFF is a standalone software tool for measurement.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, the studies evaluate the performance of the UDFF software tool itself in its ability to quantify fat fraction, either compared to a predicate device's software tool (Study 1) or to MRI-PDFF as a reference standard (Study 2). The results (Pearson Correlation, ICC, bland-Altman, AUROC) are metrics of the algorithm's performance.
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The type of ground truth used:
- Study 1: The ground truth was the Ultrasound-Derived Fat Fraction (UDFF) measurement obtained from the predicate device (ACUSON Sequoia), and the internal consistency of the ACUSON Redwood UDFF measurements (test-retest).
- Study 2: The ground truth was MRI-PDFF (Magnetic Resonance Imaging Proton Density Fat Fraction), which is a quantitative imaging biomarker considered a non-invasive gold standard for liver fat content.
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The sample size for the training set:
- The document does not provide information regarding the sample size of any training set used for the UDFF algorithm. This section focuses on validation studies.
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How the ground truth for the training set was established:
- The document does not provide information regarding how the ground truth for any potential training set was established.
§ 892.1550 Ultrasonic pulsed doppler imaging system.
(a)
Identification. An ultrasonic pulsed doppler imaging system is a device that combines the features of continuous wave doppler-effect technology with pulsed-echo effect technology and is intended to determine stationary body tissue characteristics, such as depth or location of tissue interfaces or dynamic tissue characteristics such as velocity of blood or tissue motion. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II.