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510(k) Data Aggregation
(199 days)
The QCT Pro Asynchronous Calibration Module is intended to provide an alternative method for calibrating QCT data sets that are intended for analysis with QCT Pro Spine and Hip application modules. Installation of the QCT Pro Asynchronous Calibration Module does not alter the clinical indications for use of the QCT Pro Spine and Hip application modules. It does, however, provide an additional means of obtaining calibration data that does not require the simultaneous scanning of a patient with a CT calibration standard as is required when using the QCT Pro Spine and Hip application modules without the installation of the QCT Pro Asynchronous Calibration Module. Thus the QCT Pro Asynchronous Calibration Module facilitates: (1) retrospective assessment of bone density from CT scans acquired for other purposes, (2) assessment of bone density in conjunction with another medically appropriate procedure involving CT scans of the anatomical regions where estimating bone density is prescribed, and (3) assessment of bone density without a phantom as an independent measurement procedure.
The QCT Pro Asynchronous Calibration Module is intended to extend the capabilities of QCT Pro bone mineral densitometer products (K894854. K002113. K030330) currently marketed by Mindways to the measurement of bone mineral content (BMC) and bone mineral density (BMD) from patient-specific CT images acquired without the simultaneous use of a CT calibration phantom. The QCT Pro bone mineral densitometer products distributed with or supplemented with the QCT Pro Asynchronous Calibration Module will be marketed under the name QCT Pro CliniQCT or more simply CliniQCT. Mineral calibration with the asynchronous calibration method is obtained from phantom measurements acquired on the same CT scanner, operated in a substantially similar mode used to acquire a patient CT scan. The phantom measurements used for calibration purposes may be acquired before or after a patient CT scan to which they are to be applied. The asynchronous calibration mode facilitates: (1) retrospective assessment of bone density from CT scans acquired for other purposes, (2) assessment of bone density in conjunction with another medically appropriate procedure involving CT scans of the anatomical regions where estimating bone density is prescribed, and (3) assessment of bone density without a phantom as an independent measurement procedure. Retrospective bone density analysis provides bone density information without exposing a patient to additional ionizing radiation while combining CT studies results in an overall reduction in patient exposure to ionizing radiation relative to the expected radiation dose associated with performing the studies separately.
Here's an analysis of the acceptance criteria and study detailed in the provided document, restructured to address your specific points:
The document describes the QCT Pro Asynchronous Calibration Module (marketed as CliniQCT), which provides an alternative calibration method for QCT data sets without requiring a simultaneous CT calibration phantom scan with the patient.
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Specific Metric | Acceptance Criteria (CliniQCT) | Reported Device Performance (CliniQCT) | Predicate Device Performance (QCT Pro) |
|---|---|---|---|---|
| Performance | In vitro Precision (relative to calibration reference standard) | Non-inferior to QCT Pro | Non-inferior to QCT Pro (Implied to meet or exceed predicate precision) | Volume Density: 1.4 mg/cm³ (0.7% at a nominal volume density of 200 mg/cm³)Area Density: 0.007 g/cm² (0.7% at a nominal area density of 1.0 g/cm²) |
| In vivo Precision (patient) | Non-inferior to QCT Pro | Non-inferior to QCT Pro (Implied to meet or exceed predicate precision) | Spine: Up to 1%Total Hip ROI: 0.011 g/cm² (1.1% at 1.0 g/cm²)Femoral Neck: 0.012 g/cm² (1.2% at 1.0 g/cm²) | |
| Accuracy (relative to calibration reference standard) | Unbiased | Unbiased | Unbiased | |
| Equivalence of BMC/BMD estimates | Similar to those obtained from predicate QCT Pro devices for spine and proximal femur. | CliniQCT provides estimates of bone mineral content (BMC) and bone mineral density (BMD) values similar to those obtained from the predicate QCT Pro bone densitometer devices. | Yes | |
| Safety/Usability | Radiation dose with examination | Within currently accepted guidelines and equivalent to predicate use cases. | Facilitates retrospective assessment without additional radiation exposure beyond the initial scan. | Radiation dose associated with examination is within currently accepted guidelines regarding radiation health risks associated with common radiologic diagnostic procedures. (Note: QCT Pro does not directly control radiation delivery). |
| Ability to provide retrospective measurements from CT scans acquired for other purposes. | Yes (primary benefit of asynchronous calibration) | Yes, without exposing the patient to additional ionizing radiation. | No (Predicate QCT Pro requires simultaneous phantom scanning, limiting retrospective analysis without re-scanning). | |
| Ability to provide dual-use BMD/BMC measurements from CT scans for multiple purposes. | Yes (primary benefit of asynchronous calibration) | Yes, without exposing the patient to additional ionizing radiation beyond the other, non-QCT, purpose(s). | No (Predicate QCT Pro requires simultaneous phantom scanning, making dual-use for unrelated CT scans challenging without additional radiation for QCT-specific phantom scan). |
Note: The document states that the new device has "the same technological characteristics as its predicate QCT Pro devices" with the exception of the asynchronous calibration method, and that "BMD estimates derived with the asynchronous calibration method are suitable for comparison to the same reference data sets as are used with the QCT Pro predicate devices." This implies that the performance metrics (precision, accuracy) of CliniQCT are expected to be on par with the predicate devices.
2. Sample Size Used for the Test Set and Data Provenance
The document states that the testing involved:
- Retrospective data analysis
- Phantom testing
- Prospective patient studies
However, specific sample sizes for the test set (number of images, patients, or phantoms) are not explicitly provided in the excerpt. The data provenance (e.g., country of origin, retrospective or prospective) is partially indicated by "retrospective data analysis" and "prospective patient studies," but further details (like country/institution) are missing.
3. Number of Experts Used to Establish Ground Truth and Their Qualifications
The document does not provide information regarding the number of experts used to establish ground truth or their qualifications. The device appears to be for quantitative measurements (BMC/BMD) rather than diagnostic image interpretation requiring expert consensus.
4. Adjudication Method for the Test Set
The document does not specify an adjudication method. Since the device provides quantitative measurements (BMC/BMD) rather than classification/diagnosis for which human readers would typically adjudicate, an adjudication method for a "test set" in the traditional sense of diagnostic image review is not applicable here. Performance is evaluated against objective reference standards and comparison to predicate devices.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
An MRMC comparative effectiveness study was not conducted, or at least not described in this document. The device is a quantitative measurement tool (densitometer) and not designed for human-in-the-loop diagnostic image interpretation where AI assistance to human readers would be evaluated. The focus is on the accuracy and precision of the quantitative measurements produced by the device itself, compared to existing, validated methods.
6. Standalone Performance (Algorithm Only Without Human-in-the-Loop Performance)
Yes, the study primarily describes the standalone performance of the CliniQCT device. The "non-inferiority" and "unbiased" claims for precision and accuracy directly reflect the algorithm's performance in generating BMC and BMD values. It is a tool that provides quantitative data, and its performance evaluation is centered on the accuracy and reliability of these quantitative outputs.
7. The Type of Ground Truth Used
The ground truth used for evaluating the device appears to be:
- Calibration Reference Standard: For in vitro precision and accuracy, the device's output is compared against established calibration reference standards (e.g., aqueous K2HPO4 bone density standard).
- Predicate QCT Pro device outputs: For in vivo precision and similarity of BMC/BMD estimates, the device's performance is compared against the performance characteristics of its predicate QCT Pro devices, which are already legally marketed and established.
8. The Sample Size for the Training Set
The document does not specify a separate training set sample size. The testing described ("retrospective data analysis, phantom testing and prospective patient studies") appears to be for evaluating the device's performance (validation), not for initial model training data, as the device's underlying principles are based on Quantitative Computed Tomography (QCT) and existing predicate technology.
9. How the Ground Truth for the Training Set Was Established
Since a separate "training set" is not explicitly mentioned for a machine learning model, the concept of ground truth establishment for a training set in that context is not directly applicable here. The device's calibration and underlying algorithms would be based on established QCT principles and phantom measurement protocols. The phrase "calibration data necessary for use with the QCT Pro Asynchronous Calibration Module is obtained from a standard QCT Pro QA phantom CT scan performed on the same CT scanner" suggests calibration is done using physical phantoms with known density values.
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(140 days)
The intended use of the CTXA Hip Extence Data accessory for the CTXA Hip Bone Mineral Densitometry module is to provide a context for the clinical interpretation of a patient's proximal femur BMD estimates. T-scores are calculated relative to a US normal female Caucasian reference population age 20-39 years, and Z-scores are calculated relative to a US normal female Caucasian reference population age 20-79 years. The use of a reference data set and the interpretation of parameters derived by the CTXA Hip module when comparing patient-specific BMD estimates to the installed and selected reference data set is at the discretion of the physician.
The CTXA Hip Extenced Reference Data is an accessory to the CTXA Hip Bone Mineral Densitometer. The CTXA Hip Extended Reference Data is used within the CTXA Hip module to calculate T-scores and percent young normal for any patient, and Z-scores for patients age 20-80 for BMD estimates made using the CTXA Hip module.
The provided text describes a 510(k) premarket notification for the "CTXA Hip Extended Reference Data" device, which is an accessory to the CTXA Hip Bone Mineral Densitometer. The purpose of this accessory is to provide a broader reference dataset for calculating T-scores and Z-scores for Bone Mineral Density (BMD) estimates from the CTXA Hip module.
1. A table of acceptance criteria and the reported device performance:
| Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|
| Premarket Equivalence to Predicate Device: The device must demonstrate substantial equivalence to the legally marketed predicate device (K002113: CTXA Hip Bone Mineral Densitometer) in terms of safety and effectiveness, despite the expanded reference data. | The CTXA Hip Extended Reference Data is intended to be an accessory to the CTXA Hip Bone Mineral Densitometer. The submission explicitly states: "The CTXA Hip Extended Reference Data is substantially equivalent to the listed predicate device." |
| Accuracy of BMD Estimates: BMD estimates obtained with the accessory should be consistent with those from the predicate device. | "BMD estimates obtained with CTXA Hip with Extended Reference Data accessory are identical to BMD estimates obtained with the predicate CTXA Hip." |
| Clinical Significance of T-score Differences: Any differences in calculated T-scores due to the expanded reference data should not be clinically significant. | "T-scores calculated with CTXA Hip with Extended Reference Data accessory are slightly less negative than those calculated with CTXA Hip, approximately 0.1-0.2 Tscore units. This difference is not significant clinically." |
| Clinical Interpretation: The clinical interpretation of BMD estimates made with the accessory should be comparable to that of the predicate device. | "The clinical interpretation of BMD estimates made with CTXA Hip Extence Data is comparable to that associated with the predicate device." |
| Expanded Z-score Range: The device must successfully calculate Z-scores for a broader age range (20-80 years) compared to the predicate (20-39 years). | The device description and intended use clearly indicate this expanded capability: "The current CTXA Hip Extence Data is an accessory to CTXA Hip that also is used to calculate T-scores and percent young normal, and also is used to calculate Z-scores for ages 20-80." And in Indications for Use: "Z-scores are calculated relative to a US normal female Caucasian reference population age 20-79 years." |
2. Sample size used for the test set and the data provenance:
The document does not explicitly state a specific sample size used for a test set in the context of a validation study for the "CTXA Hip Extended Reference Data" accessory itself.
Instead, the substantiation for substantial equivalence appears to rely on:
- Logical deduction: BMD estimates are "identical" to the predicate, implying the core measurement accuracy is unchanged.
- Quantification of T-score differences: A "0.1-0.2 T-score unit" difference, which is then deemed "not significant clinically."
- Reference Population: The reference data set used for T-scores and Z-scores is described as a "US normal female Caucasian reference population." The specific size, collection methodology (retrospective/prospective), or exact provenance (e.g., specific study) of this reference population is not detailed in the provided text.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
The document does not mention the use of experts to establish ground truth for a test set in the context of the device's performance evaluation. The device's function is a calculation based on predefined reference data, not a diagnostic interpretation that typically requires expert consensus for ground truth.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set:
Not applicable. The document does not describe an adjudication method for a test set, as its evaluation focuses on the consistency of calculations and the clinical insignificance of minor differences, rather than a diagnostic accuracy study where adjudication is common.
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:
Not applicable. The device, "CTXA Hip Extended Reference Data," is an accessory for a bone densitometer providing reference data for score calculation. It does not involve AI assistance to human readers or a multi-reader multi-case study. It simply provides a new reference population for existing BMD measurements.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
The device's core function is standalone in the sense that it provides a calculation of T-scores and Z-scores based on a reference database. The "algorithm" (i.e., the method of calculating these scores against the reference data) is performed without human intervention in the calculation itself. However, the interpretation of these scores "is at the discretion of the physician," meaning the overall diagnostic process remains human-in-the-loop. The document focuses on the accuracy and clinical insignificance of differences in these calculated scores.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
The "ground truth" in this context refers to the reference population data against which patient BMD estimates are compared to calculate T and Z scores. The document describes this as a "US normal female Caucasian reference population age 20-39 years" for T-scores and "US normal female Caucasian reference population age 20-79 years" for Z-scores. The specific methodology for establishing this "normal" reference population (e.g., how subjects were selected, what criteria defined "normal," how BMD was measured for this database) is not detailed in the provided text.
8. The sample size for the training set:
The document does not mention a training set in the context of machine learning or AI. The "reference data" would be analogous to a training set here, but its sample size is not specified.
9. How the ground truth for the training set was established:
The document does not detail how the "US normal female Caucasian reference population" (which serves as the "ground truth" or reference for the device's calculations) was established. It is simply referred to as a "reference population."
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(545 days)
The CTXA Hip Bone Mineral Densitometer is intended to estimate bone mineral content (BMC) and bone mineral density (BMD) in the proximal femur. The BMD estimates can be compared with CTXA Hip-derived reference data. T-scores are calculated with respect to CTXA Hip young normal female reference data, and the T-scores can be used by the physician as an aid in determining fracture risk.
The CTXA Hip Bone Mineral Densitometer (CTXA Hip) is a software package intended for estimation of bone mineral content (BMC), in grams, and bone mineral density (BMD), in glem', of the proximal femur. The CTXA Hip uses quantitative computed tomography (QCT) methods to derive bone mass and bone density estimates from 3D CT image data sets. The CTXA Hip is intended to be used with compatible, whole-body CT scanners and with compatible CT calibration phantoms. BMD estimates are derived in units of g/cm2 equivalent K2HPO4 density.
Here's a breakdown of the acceptance criteria and study details for the CTXA Hip Bone Mineral Densitometer, based on the provided 510(k) summary:
1. Table of Acceptance Criteria and Reported Device Performance
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| In vitro precision | Not explicitly stated, but expected to be low for accuracy | Approximately 0.007 g/cm² |
| In vitro bias | Unbiased when expressed as equivalent K2HPO4 density | Unbiased |
| In vivo precision (Total Hip) | Not explicitly stated, but expected to be low for clinical reliability | 0.011 g/cm² |
| In vivo precision (Femoral Neck) | Not explicitly stated, but expected to be low for clinical reliability | 0.012 g/cm² |
| Correlation with predicate DXA devices (Total Hip) | Not explicitly stated, but expected to demonstrate strong correlation (e.g., R > 0.85-0.90) | 0.90-0.97 (Pearson's R) |
| Correlation with predicate DXA devices (Femoral Neck) | Not explicitly stated, but expected to demonstrate strong correlation (e.g., R > 0.85-0.90) | 0.88-0.95 (Pearson's R) |
Note: The 510(k) summary does not explicitly state numerical acceptance criteria for many of these metrics. Instead, it reports the device performance and implicitly suggests these values are acceptable by concluding substantial equivalence to predicate devices.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: Not explicitly stated. The summary mentions "clinical studies" for both in vivo precision and correlation with predicate devices, and "a clinical study" for collecting reference data. No specific numbers are provided for patient cohorts in these studies.
- Data Provenance:
- In vitro phantom studies: Location not specified, but likely laboratory-based.
- Clinical studies (in vivo precision & correlation): Not explicitly stated, but the reference data collection mentions "young normal US Caucasian females," implying US origin for at least that part of the clinical data.
- Retrospective or Prospective: Not explicitly stated for any of the clinical studies.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of Those Experts
This information is not provided in the summary. The studies described are focused on device precision and correlation with other devices, not on diagnostic accuracy against a human-established ground truth in a direct sense.
4. Adjudication Method for the Test Set
This information is not provided in the summary. Given the nature of the device (automated bone mineral density estimation), direct human adjudication of results in the traditional sense (e.g., consensus on image interpretation) is not applicable in the same way it would be for a diagnostic AI device. The comparison is against established device outputs (DXA) or precision metrics.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not reported. The device is a "standalone" algorithm for quantitative measurement, not an AI-assisted diagnostic tool for human readers.
- Effect size of human readers improve with AI vs without AI assistance: Not applicable, as no MRMC study was performed with human readers.
6. If a Standalone Study Was Done
Yes, standalone performance was assessed. The entire submission describes the performance of the CTXA Hip software itself (an algorithm) in various scenarios:
- In vitro phantom studies: Assessed precision and bias independently.
- Clinical studies for in vivo precision: Assessed the device's consistency over time when applied to human subjects.
- Clinical studies comparing BMD results with predicate DXA devices: Evaluated the device's output against established measurement systems.
7. The Type of Ground Truth Used
- For in vitro phantom studies: The ground truth was based on the known physical properties and densities of the phantoms used, expressed as equivalent K2HPO4 mineral density.
- For in vivo precision studies: The "ground truth" was the device's own consistent measurement of BMD in the same individuals over time, aiming for low variability.
- For correlation studies with predicate devices: The "ground truth" was the BMD measurements obtained from the predicate DXA devices (Hologic QDR 1000 and QDR 4500), which are established methods for bone densitometry.
8. The Sample Size for the Training Set
This information is not provided in the summary. The CTXA Hip is described as a software package using QCT methods to derive estimates, but the details of any machine learning or specific algorithm training are not discussed. It's likely based on established QCT principles rather than a distinct "training set" in the modern AI sense.
9. How the Ground Truth for the Training Set Was Established
Since a "training set" in the typical machine learning sense is not explicitly mentioned and the device appears to be based on established QCT principles rather than being a trained AI model, the method for establishing "ground truth for the training set" is not applicable/provided. The summary focuses on validation of the methodology and its output against existing standards.
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