(116 days)
The Med-Imaps TBS iNsight is a software provided for use as a complement to a DEXA analysis. It computes the antero-posterior spine DEXA examination file and calculates a score (Trabecular Bone Score - TBS) that is compared to those of the age-matched controls. The TBS is derived from the texture of the DEXA image and has been shown to be related to bone microarchitecture and fracture risk. This data provides information independent of BMD value; it is used as a complement to the data obtained from the DEXA analysis and the clinical examination (questioning by the clinician about patient history, bioassay of bone resorption markers ... ).
The TBS score can assist the health care professional in assessment of fracture risk and in monitoring the effect of treatments on patients across time.
Overall fracture risk will depend on many additional factors that should be considered before making diagnostic or therapeutic recommendations. The software does not diagnose disease, or recommend treatment regimens. Only the health care professional can make these judgments.
TBS iNsight is a software package that provides an estimate of the trabecular bone quality based on analysis of data derived from DEXA examination. The program utilizes a quantitative bone structural algorithm that analyzes the texture of AP spine projection scans from which the Trabecular Bone Score (TBS) is mathematically derived.
The results (TBS) can be used for comparison to a reference database of age-matched controls.
Here's an analysis of the acceptance criteria and study findings for the Medimaps Group TBS iNsight software, based on the provided 510(k) summary:
1. Table of Acceptance Criteria and Reported Device Performance
The provided document does not explicitly present a table of quantitative acceptance criteria for each validation study. Instead, it describes general objectives and qualitative outcomes for each performance bench test and clinical study. However, the conclusion states that the device "met all acceptance criteria." Based on the descriptions, we can infer the objectives that served as de-facto acceptance criteria.
| Acceptance Criteria (Inferred from Study Objectives) | Reported Device Performance |
|---|---|
| Bench Tests: | |
| Correlation between Microarchitecture (3D µCT) and TBS (Simulated 2D Projections): | Significant correlations were observed between TBS and 3D microarchitecture parameters, regardless of projection resolution. |
| Correlation between Microarchitecture (3D µCT) and TBS (Actual DEXA Scans): | Significant correlations were detected between TBS and 3D parameters of bone microarchitecture. The study indicated that TBS adds value and differentiation between samples with similar BMDs but different bone microarchitectures, strengthening the assumption that bone microarchitecture can be estimated from DEXA using TBS. |
| Ex-vivo Reproducibility of TBS: | The TBS ex-vivo precision error was lower than 0.02, the CV% was lower than 1.5%, and the least significant change was lower than 4.2%. These results demonstrate TBS is reproducible and can be used to monitor microarchitecture changes over time. |
| Clinical Tests: | |
| Diagnostic Value (Differentiation of Fractured vs. Non-Fractured Patients): | In five cross-sectional studies, TBS was significantly lower in women with fractures versus without, both independently and in conjunction with BMD. |
| Prognostic Value (Prediction of Future Fractures): | In three longitudinal studies, spine TBS and BMD predicted fractures equally well and independently. |
| Monitoring Changes Across Time (In-vivo Reproducibility): | In two in-vivo reproducibility studies, the mean TBS reproducibility value (CV%) at L1-L4 achieved 1.8%, demonstrating TBS is reproducible, comparable to BMD, and adherent to ISCD rules. |
| Treatment Follow-up (Responsiveness to Treatment): | Results were consistent with published literature across six studies (various treatments vs. placebo/comparators), suggesting TBS is valuable for monitoring changes over time, especially for treated patients. |
| Age-related US Reference Data (Establish Normative Data): | Age-related normative data for non-Hispanic white US women aged 30 to 90 years was obtained. Lumbar vertebral combinations (L1, L2, L3, L4) showed significant decreases in TBS with age, reflecting age-related microarchitecture changes. |
2. Sample Sizes and Data Provenance
- Bench Test - µCT and Simulated Projections:
- Sample Size: Thirty human cadaveric vertebrae.
- Data Provenance: Ex-vivo (cadaveric tissue). Country of origin not specified, but the company is Swiss.
- Bench Test - µCT and DEXA Scans:
- Sample Size: Thirty human cadaveric vertebrae.
- Data Provenance: Ex-vivo (cadaveric tissue). Country of origin not specified.
- Bench Test - Ex-vivo Reproducibility:
- Sample Size: Not explicitly stated, but likely the same thirty human cadaveric vertebrae from the other bench tests, as it builds on them.
- Data Provenance: Ex-vivo (cadaveric tissue). Country of origin not specified.
- Clinical Studies - Diagnostic Value:
- Sample Size: Evaluated through "five cross-sectional studies." Specific sample sizes for each study are not provided.
- Data Provenance: Clinical (patient data). Retrospective/Prospective not specified for each study, but typical for cross-sectional analysis in published literature. Country of origin not specified.
- Clinical Studies - Prognostic Value:
- Sample Size: Evaluated through "three longitudinal studies." Specific sample sizes for each study are not provided.
- Data Provenance: Clinical (patient data). Longitudinal indicates prospective follow-up. Country of origin not specified.
- Clinical Studies - In-vivo Reproducibility:
- Sample Size: "Two in-vivo reproducibility studies." Specific sample sizes not provided.
- Data Provenance: Clinical (patient data). In-vivo implies prospective. Country of origin not specified.
- Clinical Studies - Treatment Follow-up:
- Sample Size: "All six studies" mentioned. Specific sample sizes not provided.
- Data Provenance: Clinical (patient data). Longitudinal and prospective (clinical trials). Country of origin not specified but likely international across multiple trials.
- Clinical Studies - Age-related US Reference Data:
- Sample Size: Non-Hispanic white US women aged 30 to 90 years. Specific number of women is not provided.
- Data Provenance: Clinical (patient data). Likely retrospective collection from a US cohort.
3. Number of Experts and Qualifications for Ground Truth (Test Set)
The document does not provide details on the number of experts used to establish ground truth for the test set or their specific qualifications (e.g., radiologist with X years of experience). The ground truth for the bench tests relied on µCT measurements, which is an objective physical measurement rather than expert consensus on images. For the clinical studies, ground truth related to fracture diagnosis/prognosis and treatment effects would typically be established by clinical diagnoses, imaging reports (potentially read by radiologists, but not explicitly stated for this purpose), and follow-up data.
4. Adjudication Method for the Test Set
The document does not describe any specific adjudication method (e.g., 2+1, 3+1) for establishing ground truth within the test sets. For the bench tests, the ground truth was objective µCT measurements, precluding the need for human adjudication of image interpretations. For clinical outcomes, fracture events, and treatment responses, these are typically clinical endpoints.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study is mentioned. The studies focus on the performance of TBS itself (correlations, reproducibility, diagnostic/prognostic value) rather than comparing human reader performance with and without AI assistance.
6. Standalone (Algorithm Only) Performance Study
Yes, the studies described are primarily standalone performance investigations of the TBS iNsight algorithm.
- The bench tests directly assess the algorithm's ability to derive TBS values that correlate with 3D microarchitecture parameters or demonstrate ex-vivo reproducibility.
- The clinical studies evaluate the direct diagnostic, prognostic, and monitoring capabilities of the calculated TBS values.
While the intended use is "as a complement to a DEXA analysis," the performance evaluation focuses on the algorithm's output (TBS) rather than its impact on a human reader's interpretation flow.
7. Type of Ground Truth Used
- Bench Tests: The primary ground truth for comparing TBS to actual bone structure was 3D microarchitecture parameters derived from µCT (micro-computed tomography) datasets. This is an objective and highly detailed measure of bone structure, often considered the gold standard for microarchitectural assessment.
- Clinical Studies (Diagnostic/Prognostic/Treatment/Reference Data): The ground truth for clinical studies implicitly relies on clinical outcomes data (e.g., confirmed fracture events, patient diagnoses of fracture status, observed response to treatment regimens). For the age-related reference data, the "ground truth" is the observed TBS values within that specific population.
8. Sample Size for the Training Set
The document does not specify the sample size for the training set used to develop the TBS iNsight algorithm. The provided information relates to validation studies, not algorithm development.
9. How Ground Truth for the Training Set Was Established
The document does not provide information on how the ground truth for the training set was established, as it focuses on the validation of the already developed device.
§ 892.1170 Bone densitometer.
(a)
Identification. A bone densitometer is a device intended for medical purposes to measure bone density and mineral content by x-ray or gamma ray transmission measurements through the bone and adjacent tissues. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II.