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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 accuDEXA is a dual-energy x-ray device indicated for use in measuring an index of the bone density of the middle finger of the nondominant hand (BMD). This BMD value is a relative indicator of bone density elsewhere in the body. The measurement is compared to similar measurements from patients of the same gender and ethnicity to provide t-scores (number of standard deviations above or below the mean for a reference group of young healthy individuals) and z-scores (number of standard deviations above or below the mean for a cohort of the same age). A t-score or a z-score may be used by a physician as one factor, in conjunction with other clinical indicators, to diagnose osteoporosis and other bone disorders. When a normative database of the same ethnicity and gender is not available, the BMD value may still be used to compare to the patient's own baseline value, for example in following the patient's response to treatment for osteoporosis.

Below normal bone density can be associated with a variety of conditions or disorders of bone. For example, the Society of Nuclear Medicine and American College of Nuclear Physicians has identified specific medical indications for measurement of a patient's bone mass: for patients with premenopausal oophorectomy, spontaneous menopause, or estrogen deficiency conditions; for treatment-related osteopenia; when the diagnosis of osteopenia is suggested or established by other means, such as x-ray; during long-term immobilization; for endocrinopathies known to be associated with osteopenia; for post-gastrectomy and other malabsorption states leading to osteopenia: during long-term corticosteroid therapy; for chronic renal disease, particularly in childhood or adolescence; and to monitor treatment programs for osteoporosis.

The accuDEXA device is a Dual Energy X-Ray Absorptiometer (DEXA) device. The device is intended to calculate an index of 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 zscore 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.

Here's an analysis of the provided text regarding the Schick accuDEXA Bone Densitometer, focusing on acceptance criteria and the supporting study:

Schick accuDEXA Bone Densitometer Acceptance Criteria and Study

The provided document, a 510(k) Summary for the Schick accuDEXA Bone Densitometer, describes the device's performance characteristics through a study to demonstrate substantial equivalence to predicate devices. While explicit "acceptance criteria" in a numerical or threshold format are not directly stated, the document implies them through its claims of precision, accuracy, and correlation with predicate devices and ground truth.

1. Table of Acceptance Criteria and Reported Device Performance

Given the nature of a 510(k) submission, the "acceptance criteria" are implied by the demonstration of performance that supports substantial equivalence to existing devices. The document highlights key performance characteristics rather than specific pass/fail values.

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

• Sample Size for Test Set: The document states the study was conducted "on cadavers" for precision and accuracy testing. It does not specify the exact number of cadavers or bone samples used in this study.
• Data Provenance: Retrospective, as it involves cadaveric tissue. The country of origin of the data is not specified.

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

• The document does not mention the number or qualifications of experts used to establish ground truth. The ground truth (ashed bone weights) is an objective physical measurement, not an expert interpretation.

4. Adjudication Method for the Test Set

• None specified. For the "ashed bone weights" ground truth, adjudication by experts would not be applicable, as it's a direct physical measurement.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• No. The document does not describe a multi-reader multi-case (MRMC) comparative effectiveness study involving human readers with and without AI assistance. The study focuses on the device's intrinsic performance (precision and accuracy) and its correlation with predicate devices.

6. Standalone Performance Study

• Yes. The primary study described evaluates the "precision and accuracy of the accuDEXA device" and its correlation with ashed bone weights. This is a standalone assessment of the algorithmic performance in determining bone density.

7. Type of Ground Truth Used

• For the accuracy evaluation, the ground truth used was "ashed bone weights." This is an objective, quantitative physical measurement of true bone mineral content.

8. Sample Size for the Training Set

• The document mentions "A reference data base has been developed in a clinical study which allows the calculation of t-scores and z-scores for each patient." However, it does not specify the sample size of this clinical study that formed the normative database.

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

• The ground truth for the "reference data base" (which acts as a training set for norm-based scoring) was established through "a clinical study." It is assumed that this clinical study involved measuring BMD in a population to derive mean and standard deviation values for different age, gender, and potentially ethnic groups, thereby establishing the normative data for t-scores and z-scores. The specific methods for establishing the "ground truth" (i.e., true bone density measurements in this clinical cohort) are not detailed beyond "measurements."

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