(269 days)
VirtuOst uses data from computed tomography scans to estimate bone mineral density, bone strength, and a load-to-strength ratio. This information can be used by a physician to assess fracture risk, identify osteoporosis, and monitor therapy. For pediatric patients, VirtuOst provides these estimates without any classifications and should be used only when the benefit of obtaining these estimates outweighs the risk of radiation.
VirtuOst is a stand-alone software package that analyzes data in computed tomography (CT) scans to measure bone mineral density (BMD), bone strength, and a load-tostrength ratio at the proximal femur and vertebral body. BMD is measured from both a 2D projection (in g/cm2) and a volumetric scan reconstruction (in mg/cm2) of the CT scan. VirtuOst measurements can be used by a physician to identify osteoporosis, assess fracture risk, and monitor therapy.
The provided text describes the VirtuOst device (K113725), which analyzes CT scans to estimate bone mineral density, bone strength, and a load-to-strength ratio for assessing fracture risk and monitoring therapy.
Here's a breakdown of the requested information based on the provided document:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state pre-defined "acceptance criteria" in a quantitative, pass/fail format typical for medical device regulatory submissions. Instead, it focuses on demonstrating substantial equivalence to predicate devices. The "performance" is described in terms of equivalence and comparative effectiveness.
| Acceptance Criterion (Implicit) | Reported Device Performance |
|---|---|
| Bone Mineral Density (BMD) Measurement (g/cm²) | VirtuOst provides measurements of areal BMD (g/cm²) and fracture risk classifications substantially equivalent to predicate device K983028 (Hologic QDR X-Ray Bone Densitometers with Estimation of Fracture Risk from BMD). |
| Volumetric BMD Measurement (mg/cm³) | VirtuOst provides measurements of volumetric BMD (mg/cm³) substantially equivalent to predicate device K894854 (QCT Bone Mineral Density Analysis Software). |
| Bone Strength & Load-to-Strength Ratio Measurement | VirtuOst provides measurements of bone strength and a load-to-strength ratio substantially equivalent to the structural properties of the whole bone provided by predicate device K072664 (GE Lunar Femur Strength Software Option). |
| Precision (Clinical Repositioning Studies) | Clinical repositioning studies demonstrated that the precision of outcomes from VirtuOst and predicate devices are equivalent. |
| Fracture Risk Assessment Effectiveness | Results from a number of clinical fracture surveillance studies demonstrated that fracture risk assessment by VirtuOst estimates of whole-bone strength and the load-to-strength ratio are at least as good as fracture risk assessment by DXA and QCT estimates of BMD. |
| In-vitro Bone Strength Equivalence (Proximal Femur & Vertebrae) | Strength of the proximal femur and vertebral body estimated using VirtuOst are statistically equivalent to strength as measured by direct mechanical testing in cadaver experiments. |
| Technological Characteristics | VirtuOst has the same technological characteristics as the predicate devices. |
| Intended Use | VirtuOst has the same intended uses as the predicate devices. |
| Safety and Effectiveness | A comparison of fundamental technological characteristics as well as of data obtained from observational clinical studies demonstrates that the performance, safety and effectiveness of VirtuOst are substantially equivalent to those of the identified predicate devices. |
2. Sample size used for the test set and the data provenance
The document states:
- "Clinical studies demonstrated the substantial equivalence for measurements of bone mineral density between VirtuOst and predicate densitometers which used either DXA or computed tomography scans as input."
- "Clinical repositioning studies demonstrated that the precision of outcomes from VirtuOst and predicate devices are equivalent."
- "Results from a number of clinical fracture surveillance studies demonstrated that fracture risk assessment by VirtuOst estimates of whole-bone strength and the load-to-strength ratio, are at least as good as fracture risk assessment by DXA and QCT estimates of BMD."
- "Strength of the proximal femur and vertebral body estimated using VirtuOst are statistically equivalent to strength as measured by direct mechanical testing in cadaver experiments."
The exact sample sizes for these "clinical studies," "clinical repositioning studies," "clinical fracture surveillance studies," and "cadaver experiments" are not specified in the provided 510(k) summary. The data provenance (country of origin, retrospective/prospective) is also not explicitly stated.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
This information is not provided in the document. The mention is of "clinical studies" and "clinical fracture surveillance studies" which would imply clinical diagnoses, but the specifics of expert involvement or their qualifications for establishing ground truth are absent.
4. Adjudication method for the test set
The adjudication method (e.g., 2+1, 3+1, none) for the test set is not specified in the provided document.
5. 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
The document does not mention an MRMC comparative effectiveness study where human readers use the AI device with and without assistance. The studies described focus on the device's standalone performance compared to existing methods or predicate devices, rather than human-in-the-loop performance improvement.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Yes, a standalone study was done. The entire submission describes the performance of the VirtuOst software as a standalone analytical tool. Its measurements are compared to predicate devices or direct mechanical testing, supporting its function without explicitly detailing a human-in-the-loop component for its primary performance evaluation. The "Summary of Performance Data" directly refers to the device's outputs for BMD, bone strength, and fracture risk assessment.
7. The type of ground truth used
Based on the descriptions:
- For bone mineral density (BMD): The ground truth appears to be established by measurements from predicate densitometers (DXA and QCT scans). This is a comparative ground truth based on established clinical measurement tools.
- For bone strength: The ground truth was direct mechanical testing in cadaver experiments.
- For fracture risk assessment: The ground truth appears to be based on clinical fracture surveillance studies, implying actual fracture outcomes or follow-up diagnoses. This is an outcomes data or clinical diagnosis type of ground truth.
8. The sample size for the training set
The document does not specify the sample size for the training set. It only discusses performance evaluation on what can be inferred as "test" or "validation" sets through clinical and non-clinical studies.
9. How the 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 does not detail the training phase or data.
§ 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.