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LiverMultiScan (LMSv3) is indicated for use as a magnetic device software application for noninvasive liver evaluation that enables the generation, display and review of 2D magnetic resonance medical image data and pixel maps for MR relaxation times.

LiverMultiScan (LMSv3) is designed to utilize DICOM 3.0 compliant magnetic resonance image datasets, acquired from compatible MR Systems, to display the internal structure of the abdomen including the liver. Other physical parameters derived from the images may also be produced.

LiverMultiScan (LMSv3) provides a number of tools, such as automated liver segmentation and region of interest (ROI) placements, to be used for the assessment of selected regions of an image. Quantitative assessment of selected regions include the determination of triglyceride fat fraction in the liver (PDFF), T2* and iron-corrected T1 (cT1) measurements. PDFF may optionally be computed using the LMS IDEAL or three-point Dixon methodology.

These images and the physical parameters derived from the images, when interpreted by a trained clinician, yield information that may assist in diagnosis.

LiverMultiScan (LMSv3) is a standalone software application for displaying 2D Magnetic Resonance (MR) medical image data acquired from compatible MR Scanners. LiverMultiScan runs on general-purpose workstations with a colour monitor, keyboard and mouse.

The main functionality of LiverMultiScan (LMSv3) includes:

• Reading DICOM 3.0 compliant datasets stored on workstations, and display of the data acquisition information
• Post-processing of MRI data to generate parametric maps of Proton Density Fat Fraction PDFF), T2*, T1 and ironcorrected T1 (cT1) of the liver.
• Quantification, and calculation of PDFF, T2* and cT1 metrics using tools such as automatic liver segmentation and ROI (region of interest) placement.
• Generation of a summary report demonstrating the quantitative assessment results of fat fraction in the liver (PDFF), T2* and iron-corrected T1 (cT1).

Here's a summary of the acceptance criteria and the study proving the device meets them, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly present a "table of acceptance criteria" with corresponding reported performance for specific metrics like sensitivity, specificity, accuracy, etc., as one might expect for a diagnostic device. Instead, the performance testing focuses on the accuracy, repeatability, reproducibility, and inter-/intra-operator variability of quantitative measurements, and particularly on demonstrating substantial equivalence to a predicate device (LMSv2).

The acceptance criteria are implicitly defined by the reported performance ranges and the conclusion that the device performs "as well as its predicate" and that "all the testing results are well within the acceptance criteria."

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

• Phantom Testing: The sample size for phantom testing is not explicitly stated as a number of phantoms, but it involved phantoms "designed to mimic the human data but provide a wider range" and covered "worst-case scenarios." The data provenance is controlled laboratory conditions, using prepared phantoms.
• In-Vivo Testing (Clinical): The study used "in-vivo volunteer data." The precise number of volunteers is not specified. The data provenance is implicitly prospective, as it refers to "volunteer scans." No country of origin is explicitly mentioned, but the submitter (Perspectum Diagnostics Ltd) is based in the United Kingdom.
• Substantial Equivalence Testing: Used both "phantom measurements" and "in-vivo measurements." The specific sample sizes for these comparisons are not detailed.

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

The document does not describe the establishment of a "ground truth" through expert consensus for the test set, specifically in the context of diagnostic accuracy. The performance testing focuses on the accuracy and variability of the quantitative measurements (cT1, T2*, PDFF) derived by the software rather than a diagnostic outcome.

For phantom testing, ground truth values are inherent to the precisely calibrated phantoms. For in-vivo testing, variability is measured, and for substantial equivalence, the comparison is against the predicate device's measurements. There is no mention of human experts establishing a ground truth for the quantitative values directly measured by the device for these performance tests.

4. Adjudication Method for the Test Set

Not applicable. The performance testing described does not involve human adjudication of diagnostic outcomes or image interpretation in the way a clinical study for sensitivity/specificity for a diagnosis would. It focuses on the quantitative output of the software.

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

No. The document describes performance testing for device accuracy, repeatability, reproducibility, and substantial equivalence to a predicate device. It does not mention an MRMC comparative effectiveness study involving human readers with and without AI assistance or an effect size of improvement.

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

Yes, the performance testing described is primarily standalone performance testing. LiverMultiScan (LMSv3) is explicitly described as a "standalone software application" and a "post-processing, standalone software device." The tests assess the algorithms' performance in generating quantitative metrics (accuracy, repeatability, reproducibility) without requiring human interpretation as part of the core measurement. Operators (trained PD operators) are involved in using the device to generate reports and place ROIs, and inter/intra-operator variability is assessed, but the fundamental measured values are algorithmically derived from the MR data.

7. Type of Ground Truth Used

• Phantom Testing: The ground truth used was established by the precisely characterized properties of the phantoms, which were designed to mimic human data over a wide range of physiological values.
• In-Vivo Testing: For the in-vivo volunteer data, the concept of "ground truth" for the measured parameters (cT1, T2*, PDFF) refers to the true physiological values within the volunteers, against which the device's precision and variability are assessed. While not explicitly stated how this "true" value would be independently confirmed, the focus is on self-consistency (repeatability, reproducibility, operator variability) of the device's measurements rather than comparison to an external gold standard like pathology.
• Substantial Equivalence Testing: The ground truth for this comparison was the performance and measurements of the legally marketed predicate device, LiverMultiScan (LMSv2.1).

8. Sample Size for the Training Set

The document does not explicitly state the sample size (or any details) for a "training set." This type of detail is typically associated with AI/machine learning models where a dataset is used to train the algorithm. While LMSv3 includes "New algorithms" like Automatic Liver Segmentation, the document does not elaborate on how these algorithms were developed or if they involved a distinct training phase with a specific dataset.

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

Since a "training set" with established ground truth is not detailed, this information is not provided in the document.

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The ultrasound imaging systems are intended for the following applications: Fetal. Abdominal. Intraoperative, Pediatric. Small Parts, Transcranial, OB/GYN (useful for visualization of the ovaries, follicles, uterus and other pelvic structures), Cardiac, Pelvic, Neonatal/Adult Cephalic, Vascular, Musculoskeletal, Superficial Musculoskeletal, and Peripheral Vascular applications.

The system also provides the ability to measure anatomical structures {fetal, abdominal, intraoperative, small organ, neonatal cephalic, adult cephalic, transesophageal, transvaginal, peripheral vessel, musculoskeletal (conventional), musculo-skeletal (superficial) and neonatal cardiac} 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 Arterial Health Package (AHP) software provides the physician with the capability to measure Intima Media Thickness and the option to reference normative tables that have been validated and published in peer-reviewed studies. The information is intended to provide the physician with an easily understood tool for communicating with patients regarding state of their cardiovascular system. This feature should be utilized according to the "ASE Consensus Statement; Use of Carotid Ultrasound to Identify Subclinical Vascular Disease and Evaluate Cardiovascular Disease Risk: A Consensus Statement from the American Association of Echocardiography; Carotid Intima-Media Thickness Task Force, Endorsed by the Society for Vascular Imaging".

The AcuNav Catheter is intended for intraluminal visualization of cardiac and great vessel anatomy and physiology as well as visualization of other devices in the heart of adult and pediative patients. The catheter is intended for imaging guidance only, not treatment delivery, during cardiac interventional percutaneous procedures.

The Quantitative Ultrasound (OUS) software provides the ability to measure the attenuation coefficient in dB/cm-MHz at 3 MHz and the backscatter coefficient in dB/cm-str at 3 MHz in a 3-cm region of interest in the liver. Quantitative Ultrasound also includes the Ultrasonically-Derived Fat Fraction (UDFF) software which provides a 3-cm by 3-cm region of interest measurement tool to report an index that can be useful as an aid to the physician in managing adult patients with hepatic steatosis.

The ACUSON S2000, S3000 Diagnostic Ultrasound Systems are multi-purpose mobile, software controlled, diagnostic ultrasound systems with an on-screen display of thermal and mechanical indices related to potential bio-effect mechanisms. Its function is to transmit and receive 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 Mode, Amplitude Doppler Mode, a combination of modes and Harmonic Imaging on a Display.

All of the transducers and the catheter based transducers will follow Track 3 acoustic labeling (AIUM 1004, IEC 2007, AIUM/NEMA 2004a) and remain unchanged from the currently cleared ACUSON S-Family systems (K172162).

Only the VTQ application has been modified, all other hardware and software features of the Diagnostic Ultrasound device remain unchanged. Only the ACUSON S2000 and S3000 systems will be updated with the software update to VE11A upon customer purchase of the Quantitative Ultrasound (QUS) application, which will be license controlled. The S1000 system does not support the VTQ application, therefore, will not be configured to support the QUS application.

The ACUSON S3000, S2000 Diagnostic Ultrasound System includes Quantitative Ultrasound (QUS) software that provides the ability to measure the attenuation coefficient (AC) and backscatter coefficient (BSC) at 3 MHz in a 3-cm region of interest in the liver. It also includes Ultrasonically-Derived Fat Fraction (UDFF) software for a 3-cm by 3-cm region of interest measurement that can aid in managing adult patients with hepatic steatosis.

Acceptance Criteria and Device Performance:

The provided document does not explicitly list numerical acceptance criteria for the QUS features (AC, BSC, UDFF) but describes their performance. The acceptance criteria for the QUS functionality appear to be demonstrated by its correlation with established methods and its intended clinical utility.

Study Details:

1. Sample Size and Data Provenance for Test Set:

   • Clinical Study Test Set: 101 participants.
   • Data Provenance: The document doesn't explicitly state the country of origin but refers to an "external clinical study." It is a prospective study as it involved acquiring acoustic property measurements from participants.
   • Phantom Study Test Set: Phantoms with known attenuation and backscatter coefficients. The number of phantoms or measurements is not specified.

2. Number of Experts and Qualifications for Ground Truth:

   • The document does not specify the number of experts or their qualifications for establishing ground truth in the clinical study.
   • For the UDFF index, the ground truth reference was MRI Proton Density Fat Fraction (MRI-PDFF), an objective imaging biomarker.
   • For steatosis grading (0, 1, 2, 3), it refers to "% hepatocytes," implying histological assessment, which is typically done by pathologists. No specific number or qualifications are given.

3. Adjudication Method for Test Set:

   • The document does not describe an adjudication method for the test set. For the UDFF index, it relies on a "least squares fit" to MRI-PDFF. For steatosis grades, it appears to rely on histological assessment without mentioning a specific adjudication process among experts.

4. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:

   • No MRMC comparative effectiveness study is mentioned for the QUS features (AC, BSC, UDFF). The study focuses on the standalone performance and correlation with reference methods.

5. Standalone Performance Study:

   • Yes, a standalone study was performed. The QUS software, including AC, BSC, and UDFF measurements, was evaluated independently.
   • The phantom study assessed the accuracy and precision of AC and BSC measurements.
   • The clinical study assessed the acoustic property measurements (AC and BSC) and the derived UDFF index in relation to MRI-PDFF and histological steatosis grades.

6. Type of Ground Truth Used:

   • Phantom Study: Known nominal values of attenuation and backscatter coefficients.
   • Clinical Study for UDFF: MRI Proton Density Fat Fraction (MRI-PDFF %) measurements were used as the reference standard to establish the UDFF index via a least squares fit.
   • Clinical Study for Steatosis Grading: Histological assessment (percentage of hepatocytes) was used to define steatosis grades (S0, S1, S2, S3), which were then correlated with UDFF and MRI-PDFF values.

7. Sample Size for Training Set:

   • The document does not explicitly specify a separate training set size for the QUS software. The clinical study with 101 participants appears to be used for the development and evaluation of the UDFF index, which is based on a "least squares fit" to MRI-PDFF measurements. This suggests the clinical data was used to train/calibrate the UDFF algorithm.

8. How Ground Truth for Training Set Was Established:

   • Assuming the clinical study data (101 participants) served as the primary data for establishing the UDFF index:
     • MRI-PDFF: This is an objective measurement obtained from magnetic resonance imaging.
     • Steatosis Grade: Defined by the percentage of hepatocytes, which is determined through histological examination (pathology).

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