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The accuDEXA is a dual-energy x-ray device indicated for use in estimating the bone density of the middle finger of the non-dominant hand (BMD). This BMD value is a relative indicator of bone density elsewhere in the body. accuDEXA BMD estimates can be used as an aid to the physician in determining fracture risk.

The accuDEXA device is a Dual Energy X-Ray Absorptiometer (DEXA) device. The device is intended to estimate bone mineral density in the middle finger of the non-dominant hand. By changing the high voltage on the X-ray tube, two energies are produced. Each of the two settings produces an image of the finger and each image is analyzed using various algorithms to produce a value of bone mineral density (BMD) and bone mineral content (BMC). These values are compared with a normative database, yielding a t-score and a z-score. The t-score is the number of standard deviations that the patient is above or below the mean of a reference sample of young healthy individuals. The z-score is the number of standard deviations that the patient is above or below the mean of a reference sample of individuals of the same age as the patient.

The provided 510(k) summary for the Schick accuDEXA Bone Densitometer does not contain the detailed clinical study information requested to fill out the table and answer all the questions. The submission focuses on demonstrating substantial equivalence to a predicate device (Norland pDEXA and Model 178) based on technological characteristics and indications for use, rather than presenting a new clinical study with acceptance criteria and performance data.

Specifically, the document states:

• "The accuDEXA Bone Densitometer is substantially equivalent to the Norland pDEXA and Model 178 bone densitometer devices with respect to the fracture risk claim."
• "The addition to the indications statement for the accuDEXA and the indications statement cleared by FDA for the predicate device are the same. The accuDEXA Bone Densitometer has the same technological characteristics as the predicate devices."
• "Schick Technologies has demonstrated through its comparison of characteristics with the predicate devices that the accuDEXA Bone Densitomctor is substantially equivalent to the predicate devices."

This means that Schick Technologies did not conduct a new clinical study to prove the device meets specific acceptance criteria for fracture risk determination. Instead, they leveraged the existing clearance of predicate devices that had already established their utility for fracture risk assessment. There is no new performance data or acceptance criteria reported for the accuDEXA itself in this document.

Therefore, most of the requested information cannot be extracted from this specific 510(k) submission.

However, I can populate the table and answer questions based on the information provided about the premise of substantial equivalence, which is that the device should perform "the same" as the predicate.

Device: Schick accuDEXA Bone Densitometer

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample size used for the test set and the data provenance (e.g., country of origin of the data, retrospective or prospective)

• Sample Size for Test Set: Not applicable / Not provided. The submission relies on substantial equivalence to predicate devices, not on a new clinical study with a test set.
• Data Provenance: Not applicable / Not provided for the accuDEXA itself. The predicate devices (Norland pDEXA and Model 178) were already on the market, originating from earlier clearances (K973104, K931996 for pDEXA, and pre-1976 for Model 178).

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g., radiologist with 10 years of experience)

• Number of Experts: Not applicable / Not provided. No new ground truth establishment process for a test set is described. The basis for fracture risk determination for the predicate devices would have been established through a combination of clinical research and expert consensus over time, but these details are not provided here for the accuDEXA.

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set

• Adjudication Method: Not applicable / Not provided. No new test set or adjudication process is described in this 510(k) submission.

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

• MRMC Study: No. This submission describes a bone densitometer, which measures bone mineral density, not an AI-assisted diagnostic imaging interpretation device. Therefore, an MRMC study comparing human readers with and without AI assistance is not relevant to this device and was not conducted.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

• Standalone Performance Study: Not applicable in the context of fracture risk determination as a standalone claim. The device itself (accuDEXA) calculates BMD, t-score, and z-score autonomously. However, these estimates are explicitly stated to be "an aid to the physician in determining fracture risk," indicating a human-in-the-loop model where the physician interprets the device's output within the broader clinical context. The 510(k) does not present a study directly linking the algorithm's output alone to fracture outcomes without physician interpretation.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

• Ground Truth Type: Not explicitly stated for the accuDEXA. For the general understanding of bone densitometry and fracture risk, the "ground truth" for the predicate devices and the underlying science of BMD would be based on:
  • Clinical Outcomes Data: Longitudinal studies correlating low BMD with increased fracture incidence.
  • Expert Consensus: Guidelines from organizations like the World Health Organization (WHO) and National Osteoporosis Foundation (NOF) which define osteopenia and osteoporosis based on T-scores and relate these to fracture risk. The submission explicitly mentions using these recommendations.

8. The sample size for the training set

• Training Set Sample Size: Not applicable / Not provided. The submission focuses on substantial equivalence based on technological characteristics, not on a machine learning model that requires a discrete training set. The device compares patient values to a "normative database," which serves as a reference, but its size is not specified here.

9. How the ground truth for the training set was established

• Ground Truth Establishment for Training Set: Not applicable / Not provided. As above, this is not a machine learning submission. The "normative database" would have been established through large-scale epidemiological studies to define age- and gender-specific bone density distributions, which then form the basis for t-scores and z-scores, but the specifics are not in this document.

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The PIXI™ young adult reference population for os calcis and forearm provides the ability to compare the BMD result of the PIXI™ to the value of an average young adult, age 20-45 years old, of the same sex. The results from this comparison are expressed as a percentage of young adults, or as a T-score, defined as a number of standard deviations from the young adult value.

This additional feature is highly comparable to similar features in the Norland pDEXA as well as the Osteon Osteoanalyzer densitometers.

The use of the PIXI™ young adult reference population for os calcis and forearm, is restricted to prescription use only.

The reference BMD values incorporated in this submission, provides the ability to compare the BMD result of the PIXI™, to the value of an average young adult, age 20 - 45 years old, of the same sex. The results from this comparison are expressed as a percentage of young adult, or as a T-Score, defined as number of standard deviations from the young adult value.

The provided text describes a 510(k) submission (K972053) for the PIXI™ young adult reference population for os calcis and forearm, which is an enhancement to a bone densitometer. The submission focuses on establishing descriptive reference data rather than a device's diagnostic performance against a specific disease. Therefore, the traditional acceptance criteria and study design for diagnostic devices (e.g., sensitivity, specificity, reader studies with AI assistance) are not directly applicable in the same way.

Instead, the "acceptance criteria" here relate to the adequacy and representativeness of the reference population data for calculating T-scores and percentage comparisons. The "study" is the data collection process for this reference population.

Here's an attempt to structure the information based on your request, adapting where necessary given the nature of the submission:

Acceptance Criteria and Study for PIXI™ Young Adult Reference Population for Os Calcis and Forearm (K972053)

This 510(k) submission describes the integration of a new reference population into the PIXI™ bone densitometer. The primary "performance" being evaluated is the generation of statistically sound and representative normative data for young adults (20-45 years old) to allow for the calculation of T-scores (number of standard deviations from the young adult mean) and percentage comparisons. Since this is a reference dataset for a measurement device, traditional diagnostic performance metrics (e.g., sensitivity, specificity, AUC) are not presented.

1. Table of Acceptance Criteria and Reported Device Performance

• Female: n=143, Mean=0.556, SD=0.089
• Male: n=107, Mean=0.682, SD=0.106

Forearm:

• Female: n=126, Mean=0.523, SD=0.062
• Male: n=91, Mean=0.623, SD=0.085 |
  | Demographic Representativeness: Data collected from a "normal white young adult" population as appropriate for the intended use. | Data collected on "normal white young adult men and women, age 20 to 45 years." (Specific country of origin not stated but implied to be North America given the submitter's location). |
  | Comparability to Predicate Devices: The method of using reference values is consistent with existing, legally marketed bone densitometers. | "The use of reference values with the PIXI™ bone densitometer is comparable to how reference values are utilized on other commercially available bone densitometers." The feature is also stated to be "highly comparable to similar features in the Norland pDEXA as well as the Osteon Osteoanalyzer densitometers" (identified as predicate devices). This indicates functional equivalence. |
  | No New Safety and Effectiveness Questions: The addition of this reference population does not introduce new risks or concerns. | "No new safety and effectiveness questions are raised with PIXIM young adult reference population for os calcis and forearm." |

2. Sample Size Used for the Test Set and Data Provenance

In this context, the "test set" is the population from which the reference data was collected.

• Sample Size:
  • Os Calcis: 143 females and 107 males.
  • Forearm: 126 females and 91 males.
• Data Provenance:
  • Country of Origin: Not explicitly stated but the company (LUNAR Corporation) is based in Madison, WI, USA, strongly implying US-based data collection.
  • Retrospective or Prospective: Not explicitly stated. However, the phrasing "Data were collected on normal white young adult men and women" suggests a prospective collection of data for the purpose of establishing this reference.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

• This is not applicable in the traditional sense for this submission. The "ground truth" here is the measured BMD values themselves from the healthy young adult population. There is no diagnostic classification being made that would require expert consensus for ground truth. The expertise would lie in the design of the study, proper operation of the densitometer, and statistical analysis of the collected data. The submission does not detail who designed or executed the data collection.

4. Adjudication Method for the Test Set

• Not applicable. There is no diagnostic uncertainty or disagreement requiring adjudication in the collection of these normative BMD values.

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. This submission is for a reference population used in a bone densitometer feature, not an AI-based diagnostic tool that assists human readers in interpreting images.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done

• This concept doesn't directly apply here. The "algorithm" in this case is the statistical calculation of T-scores and percentage comparisons using the collected reference data. The device's primary function (measuring BMD) is standalone, and the reference population provides comparative context to that measurement. There isn't an "algorithm only" performance separate from the reported means and standard deviations of the reference data.

7. The Type of Ground Truth Used

• The "ground truth" is the measured Bone Mineral Density (BMD) values from a defined population of "normal white young adult men and women, age 20 to 45 years." It's not clinical outcomes, pathology, or expert consensus on a diagnostic finding. It represents a statistical description of a healthy population.

8. The Sample Size for the Training Set

• In this context, the "training set" is essentially the same as the "test set" described for the reference population. The data collected constitutes the reference (training) data for future comparisons.
  • Os Calcis: 143 females and 107 males.
  • Forearm: 126 females and 91 males.

9. How the Ground Truth for the Training Set Was Established

• The ground truth (i.e., the BMD values themselves) for this reference population was established through direct measurement using a bone densitometer (presumably the PIXI™ device itself or a similar predicate device). The data was collected from "normal white young adult men and women, age 20 to 45 years," implying a recruitment process for healthy individuals within this demographic range. The submission does not detail the specific methodology for subject recruitment or measurement protocols beyond stating the demographic and the measured sites.

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