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510(k) Data Aggregation
(175 days)
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."
| Metric / Test Type | Acceptance Criteria (Implicit from Study Conclusion) | Reported Device Performance (Summary) |
|---|---|---|
| Phantom Testing | ||
| T1 Accuracy | T1 measurements consistent with literature-reported underestimation for MOLLI techniques. | Up to 18.89% lower to ground truth (95% CI Limits of Agreement) |
| T2* Accuracy | Accurate over expected physiological range. | -9.31% to 7.53% of ground truth (95% CI Limits of Agreement) |
| DIXON PDFF Accuracy (<30%) | Relatively accurate over expected physiological range; minor deviations due to known fat bias. | -7.37% to 1.72% (95% CI Limits of Agreement) |
| DIXON PDFF Accuracy (>30%) | Relatively accurate over expected physiological range; minor deviations due to known fat bias. | -28.93% to 6.83% (95% CI Limits of Agreement) |
| IDEAL PDFF Accuracy (<30%) | Accurate over expected physiological range. | -1.17% to 1.43% (95% CI Limits of Agreement) |
| IDEAL PDFF Accuracy (>30%) | Accurate over expected physiological range. | -5.05% to 10.70% (95% CI Limits of Agreement) |
| T1 Repeatability (same scanner) | Highly repeatable. | -13.88 to 14.47 ms (95% CI Limits of Agreement) |
| T2* Repeatability (same scanner) | Highly repeatable. | -0.89 to 1.43 ms (95% CI Limits of Agreement) |
| DIXON PDFF Repeatability (<30%) | Highly repeatable. | -0.66 to 0.82 % (95% CI Limits of Agreement) |
| DIXON PDFF Repeatability (>30%) | Highly repeatable. | -2.11 to 1.96% (95% CI Limits of Agreement) |
| IDEAL PDFF Repeatability (<30%) | Highly repeatable. | -1.27 to 0.87% (95% CI Limits of Agreement) |
| IDEAL PDFF Repeatability (>30%) | Highly repeatable. | -3.80 to 1.93 % (95% CI Limits of Agreement) |
| T1 Reproducibility (different scanners) | Reproducible between different scanners. | -2.66 to 10.78% (95% CI Limits of Agreement) |
| T2* Reproducibility (different scanners) | Reproducible between different scanners. | -3.43 to 2.42 ms (95% CI Limits of Agreement) |
| DIXON PDFF Reproducibility (<30%) | Reproducible between different scanners. | -1.86 to 5.95% (95% CI Limits of Agreement) |
| DIXON PDFF Reproducibility (>30%) | Reproducible between different scanners. | -8.64 to 23.52% (95% CI Limits of Agreement) |
| IDEAL PDFF Reproducibility (<30%) | Reproducible between different scanners. | -1.99 to 2.80% (95% CI Limits of Agreement) |
| IDEAL PDFF Reproducibility (>30%) | Reproducible between different scanners. | -13.46 to 6.98% (95% CI Limits of Agreement) |
| In-Vivo Testing | ||
| cT1 Repeatability | Highly repeatable. | -94.38 to 63.38 ms (ROI); -76.93 to 59.39 ms (Segmentation) |
| T2* Repeatability | Highly repeatable. | -6.07 to 5.70 ms (ROI) |
| DIXON PDFF Repeatability | Highly repeatable. | -1.77 to 3.64 % (ROI); -1.20 to 1.06% (Segmentation) |
| IDEAL PDFF Repeatability | Highly repeatable. | -1.92 to 1.54% (ROI); -1.83 to 1.28 % (Segmentation) |
| cT1 Reproducibility (between scanners) | Reproducible between scanners. | -89.70 to 120.58 ms (ROI); -84.91 to 121.79 ms (Segmentation) |
| T2* Reproducibility (between scanners) | Reproducible between scanners. | -3.68 to 6.35 ms (ROI) |
| DIXON PDFF Reproducibility (between scanners) | Reproducible between scanners. | -6.21 to 2.63% (ROI); -3.14 to 0.88% (Segmentation) |
| IDEAL PDFF Reproducibility (between scanners) | Reproducible between scanners. | -2.66 to 2.77% (ROI); -1.74 to 1.21% (Segmentation) |
| cT1 Intra-Operator Variability | Variation well within prescribed criteria; minor additional variation for ROI method. | -27.38 to 28.33ms (ROI); -20.81 to 13.06ms (Segmentation) |
| T2* Intra-Operator Variability | Variation well within prescribed criteria; minor additional variation for ROI method. | -2.29 to 2.91 ms (ROI) |
| DIXON PDFF Intra-Operator Variability | Variation well within prescribed criteria; minor additional variation for ROI method. | -0.78 to 1.90 % (ROI); -0.29 to 0.45% (Segmentation) |
| IDEAL PDFF Intra-Operator Variability | Variation well within prescribed criteria; minor additional variation for ROI method. | -1.26 to 1.05% (ROI); -0.16 to 0.14% (Segmentation) |
| cT1 Inter-Operator Variability | Variation well within prescribed criteria; minor additional variation for ROI method. | -48.05 to 39.89ms (ROI); -37.84 to 26.51ms (Segmentation) |
| T2* Inter-Operator Variability | Variation well within prescribed criteria; minor additional variation for ROI method. | -2.64 to 4.90 ms (ROI) |
| DIXON PDFF Inter-Operator Variability | Variation well within prescribed criteria; minor additional variation for ROI method. | -2.27 to 4.57% (ROI); -0.55 to 1.22% (Segmentation) |
| IDEAL PDFF Inter-Operator Variability | Variation well within prescribed criteria; minor additional variation for ROI method. | -2.09 to 1.82 % (ROI); -0.37 to 0.26% (Segmentation) |
| cT1 Worst-Case Variability | Highly reproducible. | -126.52 to 104.19 ms (ROI); -65.27 to 120.27 ms (Segmentation) |
| T2* Worst-Case Variability | Highly reproducible. | -3.68 to 6.35 ms (ROI) |
| DIXON PDFF Worst-Case Variability | Highly reproducible. | -2.04 to 0.76 % (ROI); -2.72 to 1.24% (Segmentation) |
| IDEAL PDFF Worst-Case Variability | Highly reproducible. | -3.75 to 2.83% (ROI); -1.92 to 1.35% (Segmentation) |
| Substantial Equivalence (LMSv3 vs. LMSv2.1) | Performs as well as its predicate. | |
| Phantom T1 | Negligible difference. | -1.96 to 2.09ms (95% CI Limits of Agreement) |
| Phantom T2* | Negligible difference. | -0.08 to 0.08ms (95% CI Limits of Agreement) |
| Phantom DIXON PDFF (< 30%) | Within 1% of predicate. | -0.18 to 0.10 % (95% CI Limits of Agreement) |
| Phantom DIXON PDFF (≥ 30%) | Within 2% of predicate. | -1.62 to 1.02 % (95% CI Limits of Agreement) |
| In-vivo T1 | cT1 values within 30ms of predicate. | -28.08 to 28.73ms (95% CI Limits of Agreement) |
| In-vivo T2* | T2* values within 2ms of predicate. | -0.43 to 1.69ms (95% CI Limits of Agreement) |
| In-vivo DIXON PDFF | Negligible difference. | -0.18 to 0.10 % (95% CI Limits of Agreement) |
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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