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The Infrascanner is indicated for the detection of traumatic supratentorial hematomas of as small as 3.5mL and as deep as 2.5 cm from brain surface, but not both at the same time, as an adjunctive device to the clinical evaluation in the acute hospital setting of adult patients and pediatric patients aged 2 years and older with suspected traumatic supratentorial intracranial hematoma. The device is indicated to assess patients for CT scans but should not serve as a substitute for these scans, the device should only be used to rule in subjects for the presence of hematoma, never to rule out. The Infrascanner is indicated for use by Physicians, or under the direction of a physician, who has been trained in the use of the device.

The device is a noninvasive device, which uses near-infrared spectroscopy ("NIRS") to provide early information about the possible development of traumatic supratentorial intracranial hematomas in patients presenting to hospitals with head trauma. This technology involves comparing regional differences in absorbance of NIR light. The application of NIRS to hematoma evaluation is based on the principle that intracranial hemoglobin concentration will differ where a hematoma is present, compared to hemoglobin concentrations in normal intracranial regions. The system consists of a Class I NIR-based sensor. The sensor is optically coupled to the patient's head through two disposable light guides in a "hairbrush" configuration. Examination with the Infrascanner is performed through placement of the sensor on designated areas of the head that represent the most common locations for traumatic hematoma. The examination is designed to be performed within two minutes.

Here's an analysis of the Infrascanner Model 2500's acceptance criteria and the study proving it meets them, based on the provided FDA 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for substantial equivalence are based on a comparison between the upgraded Infrascanner Model 2500 (subject device) and its predicate (the existing Infrascanner Model 2500 cleared under K211617). The primary change in the subject device is an increase in laser power from 100mW to 200mW to improve readings in very dark-skinned individuals. The acceptance criteria essentially boil down to demonstrating that this change does not negatively impact performance and, ideally, shows improvement in the area it aims to address.

• 100mW in 71 patient subgroup: 100.0% (CI: 88.4-100)
• 200mW in 71 patient subgroup: 96.7% (CI: 82.8-99.9)
  Conclusion: Equivalent sensitivity. (Note: CI overlap supports equivalence despite slightly lower point estimate for 200mW). |
  | - Specificity | In patients with no hematomas, the specificity of the 200mW device should be equivalent to the 100mW device. Implicitly, the lower bound of the 95% CI for specificity of the 200mW device should not be significantly lower than that of the 100mW device, or show improvement. | Specificity:
• 100mW in 71 patient subgroup: 36.6% (CI: 22.1-53.1)
• 200mW in 71 patient subgroup: 43.9% (CI: 28.5-60.3)
  Conclusion: Equivalent specificity. (The 200mW specificity is slightly higher, with overlapping CIs, supporting equivalence or slight improvement). |
  | - Ability to Measure Dark Skin| The 200mW device should be able to complete measurements in individuals where the 100mW device cannot due to very dark skin. | In three very dark skin individuals where measurements could not be collected with 100mW scanner, the proposed 200mW setting scanner was able to complete the measurements.
  Conclusion: Achieved the intended improvement. |
  | Other (Bench) Testing: | Compliance with relevant IEC standards (IEC 60601-1, IEC 60601-1-2, AIM 7351731 RFID Immunity, IEC 60825-1). | All listed IEC tests yielded acceptable results. |

2. Sample Size and Data Provenance for the Test Set

• Clinical Test Set Sample Size:
  • Overall study cohort: 387 patients
  • Patients with hematomas within detection range of Infrascanner: 138 patients
  • Subgroup randomly selected for 100mW and 200mW comparisons: 71 patients (30 of whom had hematomas within detection range)
• Data Provenance: The clinical study was conducted in Mbarara Hospital in Uganda. The study was prospective, as it evaluated "672 consecutive patients with confirmed or suspected head trauma who received a head CT scan," and then a subset was further analyzed with the Infrascanner.

3. Number of Experts and their Qualifications for Ground Truth

The document does not explicitly state the number of experts or their qualifications for establishing the ground truth. However, the ground truth was based on head CT scans, which implies interpretation by qualified medical professionals, most likely radiologists.

4. Adjudication Method for the Test Set

The document does not describe a specific adjudication method (like 2+1 or 3+1) for the interpretation of the CT scans or Infrascanner results. The CT scan results appear to have been taken as the definitive ground truth for hematoma presence and size.

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

• No, an MRMC comparative effectiveness study was not explicitly done in the sense of comparing human readers with and without AI assistance.
• This study evaluates the standalone performance of the Infrascanner device itself, and specifically how the increased laser power affects its ability to detect hematomas in different skin types and its overall diagnostic metrics compared to its predecessor. The Infrascanner is presented as an "adjunctive device to the clinical evaluation," meaning it aids human decision-making, but the study focuses on the device's inherent diagnostic accuracy rather than the improvement of human readers when using the device.

6. Standalone Performance

• Yes, a standalone performance evaluation was done. The sensitivity, specificity, PPV, and NPV presented in Table 3 directly represent the algorithm-only performance of the Infrascanner Model 2500 (both 100mW and 200mW versions) against the CT scan ground truth.
• The device is intended to "rule in subjects for the presence of hematoma, never to rule out," and its performance metrics reflect this intended standalone screening capability.

7. Type of Ground Truth Used

The ground truth used for the clinical study was CT scans (Computed Tomography scans) of the head. This is stated as "confirmed or suspected head trauma who received a head CT scan" and "Overall Infrascanner and CT data were available for 387 patients."

8. Sample Size for the Training Set

The document does not explicitly state the sample size for the training set used to develop or refine the Infrascanner algorithm. It focuses on the validation of the modified device. Given that the subject device is an upgrade of an existing device (predicate), the original algorithm would have been developed using a prior training set, which is not detailed here. The clinical study described here serves more as a retraining or validation set for the performance of the upgraded hardware.

9. How Ground Truth for the Training Set Was Established

As the training set details are not provided, the method for establishing its ground truth is also not described in this document. Assuming the original predicate device (K211617) followed a similar validation methodology, it is highly probable that its training ground truth was also established using CT scans of the head, as CT is the gold standard for detecting intracranial hematomas.

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