(81 days)
The EXPERT-XL Lateral Spine BMD Acquisition and Analysis software is used with the EXPERT-XL bone densitometer system. This software feature estimates bone mineral density (BMD) of the lumbar spine vertebrae in the lateral view. This BMD value can then be compared to a reference population at the sole discretion of the physician.
The EXPERT-XL Lateral Spine BMD Acquisition and Analysis Software is an accessory software option for estimation of Bone Mineral Density (BMD), in g/cm2, of the lumbar spine vertebrae in the lateral view provided for the EXPERT-XL Bone Densitometer with a reference population for comparative purposes.
This device, the EXPERT-XL Lateral Spine BMD Acquisition and Analysis Software, is an accessory for the EXPERT-XL Bone Densitometer. It is designed to estimate Bone Mineral Density (BMD) of the lumbar spine in the lateral view.
Here's an analysis of the provided information regarding its acceptance criteria and the supporting study:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| In vitro Correlation with known phantoms (BMD) | High correlation (r = 0.99) with BMD on known phantoms. |
| In vitro Precision | Equivalent to the AP spine when analyzed with a region-of-interest (ROI) of the same dimension. |
| In vivo Short Term Precision (CV) | 3.0 to 3.5%; acknowledged as higher than AP spine BMD due to smaller ROIs and lower bone density, but considered "acceptable for the small ROI". |
| Radiation Exposure (skin entrance) | 120 mrem; acknowledged as higher than for the AP view but necessary and remains low compared to the maximum permissible dose. |
| Female Reference Population (BMD changes with age) | Relatively constant BMD for ages 20-49. BMD decreases after age 50 at a rate of 0.008 g/cm² per year (approximately 1% per year). This is a descriptive characteristic rather than a strict performance metric, indicating the software's ability to provide age-stratified data. |
| Substantial Equivalence | The device is deemed substantially equivalent to the EXPERT-XL standard anterior (AP) spine projection. This is the overarching acceptance criterion for 510(k) clearance. |
2. Sample Size and Data Provenance
- Test Set Sample Size: The document does not explicitly state the sample size used for the in vitro and in vivo precision and correlation tests.
- Data Provenance: Not specified. It's unclear if the data was retrospective or prospective, or the country of origin.
3. Number of Experts for Ground Truth and Qualifications
- The document does not provide information on the number of experts used to establish ground truth or their qualifications. The "known phantoms" for in vitro testing would inherently have an established ground truth, but the in vivo data's ground truth establishment method is not detailed.
4. Adjudication Method
- The document does not describe any adjudication method.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- A multi-reader multi-case (MRMC) comparative effectiveness study was not mentioned in the provided text. The submission focuses on device performance metrics rather than human reader improvement with AI assistance.
6. Standalone Performance Study
- Yes, a standalone performance study was implicitly done. The "reported device performance" noted in the table above refers to the algorithmic performance of the software itself in measuring BMD. This includes in vitro correlation and precision, as well as in vivo precision, without explicit mention of human interpretation influencing these results.
7. Type of Ground Truth Used
- For in vitro testing: "Known phantoms" imply a precisely measured or known BMD value, serving as an objective ground truth.
- For in vivo testing: The ground truth for the "average short term precision (CV) in vivo" is based on repeat measurements on human subjects. This is a measure of reproducibility, where the "ground truth" for a given subject at a given time is essentially the value obtained by the device itself, and the precision metric assesses the variability around this. It does not explicitly state an independent "gold standard" for the absolute BMD values in vivo.
8. Sample Size for the Training Set
- The document does not specify a training set sample size. It's likely that the software's algorithms were developed and refined (trained) using a dataset, but this information is not provided.
9. How Ground Truth for the Training Set Was Established
- The document does not specify how the ground truth for any training set was established. Given the nature of a bone densitometer, training would likely involve a combination of phantom data (with known BMD) and clinical data where BMD might be established through various means (e.g., other densitometry methods, or clinically accepted values). However, this is not detailed here.
§ 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.