(102 days)
The PeriCam PSI is intended for non-invasive two-dimensional imaging of peripheral tissue blood perfusion. This can be used in a wide range of applications and disciplines including dermatology, wound healing, burns assessment etc.
The PeriCam PSI is a device to perform non-contact imaging of tissue blood perfusion in the microcirculation, for example skin, using Laser Speckle contrast analysis. The full measurement area surface is illuminated with a laser beam resulting in a laser speckle pattern. The pattern is imaged by a CCD camera and image processing of the speckle contrast is used to generate high resolution color code images showing the blood perfusion in the tissue.
Here's an analysis of the provided text regarding the acceptance criteria and study for the PeriCam PSI device:
1. Table of Acceptance Criteria and Reported Device Performance
The provided text does not explicitly state numerical acceptance criteria in terms of performance metrics (e.g., sensitivity, specificity, accuracy, or a threshold for "similar response"). Instead, the acceptance criteria are implicitly defined by the concept of "substantial equivalence" to predicate devices. The performance data focuses on demonstrating this equivalence through comparative studies.
| Acceptance Criterion (Implicit) | Reported Device Performance |
|---|---|
| Substantial Equivalence to PIM Laser Doppler Perfusion Imager (K920844) in Measurement Response | "Several comparative studies of the new device and the predicate device have been performed to show, the substantial equivalence of the two devices. These include absolute measurements as well relative response to provocations such as heating and occlusion. It can be seen that the response is very similar between the two devices for the intended use of the instruments. It can thus be concluded that the two devices show substantial equivalence." The text emphasizes that while the techniques (LASCA vs. Laser Doppler) are different, their integration times can be selected to give "similar response to flow changes for the relevant measurement objects." |
| Improved Laser Safety compared to PIM Laser Doppler Perfusion Imager (K920844) | PeriCam PSI is classified as a Class 1 laser product (IEC 60825-1:2007), which is considered safe for long-term intra-beam viewing. The predicate PIM Laser Doppler is Class 2 (IEC 60825-1:1993+A1:1997+A2:2001), for which staring into the beam must be avoided. The new device is therefore "safer" due to a wider, homogenous light distribution despite higher total laser radiation. |
| Faster Acquisition Rate compared to PIM Laser Doppler Perfusion Imager (K920844) | PeriCam PSI has a frame-rate of up to 100 fps for a complete flowmap. The predicate PIM Laser Doppler takes "minutes" for larger areas due to sequential measurement. This is described as a "huge advantage." |
| Substantial Equivalence to moorFLPI Full Field Laser Perfusion Imager (K063586) in Measurement Effectiveness | "From the description of the technological character stics it can be concluded that the PeriCam PSI and the moorFLPI Full Field Laser Perfusion Imager are equally effective in measuring tissue perfusion. The two devices measure using the same fundamental property of reduction of the speckle contrast from blurring caused by moving objects. Thus it can be concluded that the PeriCam PSI show substantial equivalence to the moorFLPI Full Field Laser Perfusion Imager in terms of the measurement effectiveness." The text notes both use a wide divergent NIR laser beam and share "approximately the same areas and acquisition rates." |
| Equivalent Laser Safety compared to moorFLPI Full Field Laser Perfusion Imager (K063586) | Both devices are classified as Class 1 laser products (PeriCam PSI: IEC 60825-1:2007; moorFLPI: IEC 60825-1:2001). "Since both instruments are assigned to laser Class 1 there are no limitations to safe use of the instruments. There is not considered to be any hazard in using the instruments." Therefore, "the hazard of using the two instruments is identical." |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The document repeatedly mentions "Several comparative studies" and "comparative studies" but does not specify the sample size (number of subjects, measurements, or data points) for these studies.
- Data Provenance: The document does not explicitly state the country of origin of the data or whether the studies were retrospective or prospective. Given that the manufacturer is Swedish (Perimed AB, Järfälla, Sweden) and the predicate device is also mentioned as being from Perimed (PIM 3 Laser Doppler Perfusion Imager PIM 3), it's highly probable the studies were conducted by the manufacturer, likely in Sweden or a related research setting. The nature of the studies (comparative performance with provocations) suggests prospective data collection in a controlled environment. However, this is an inference, not explicitly stated.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
The concept of "ground truth" as it's typically understood in diagnostic AI (e.g., pathology, clinical outcome data) is not directly applicable here. This submission is for a medical device (PeriCam PSI) that measures physiological parameters (blood perfusion), not for a diagnostic algorithm that interprets images for disease.
The "ground truth" in this context is the actual blood perfusion measurement from an established, substantially equivalent device. The comparative studies aim to show that the new device's readings match those of the predicate device under various conditions. Therefore, there's no mention of experts establishing a separate "ground truth" to which the device readings are compared. The predicate device itself acts as the reference.
4. Adjudication Method for the Test Set
Not applicable. As described above, the studies involve direct comparison of measurements between devices, not adjudication of interpretations by human experts.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
No, an MRMC comparative effectiveness study was not done. The document describes comparative studies of the new device against predicate devices to demonstrate substantial equivalence in measurement output, not a study of human readers using the device.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
Yes, the studies described are inherently "standalone" in the sense that they evaluate the device's measurement performance (algorithm + hardware) directly against predicate devices. The PeriCam PSI is a measurement device that generates color-coded flow maps; its performance is evaluated based on the similarity of these measurements to existing technology, not on human interpretation of the output.
7. The Type of Ground Truth Used
The "ground truth" is established by the measurements from the predicate device(s) (PIM Laser Doppler Perfusion Imager K920844, and implicitly moorFLPI Full Field Laser Perfusion Imager K063586). The studies directly compared the absolute measurements and relative responses to provocations (heating, occlusion) between the PeriCam PSI and the predicate device.
8. The Sample Size for the Training Set
Not applicable. The PeriCam PSI is a measurement device based on physical principles (Laser Speckle Contrast Analysis), not a machine learning algorithm that requires a "training set" in the conventional sense. Its "training" or calibration would involve ensuring the physical parameters and algorithms are correctly implemented to yield accurate and consistent measurements, not learning from a labeled dataset.
9. How the Ground Truth for the Training Set was Established
Not applicable, as there is no "training set" in the context of a machine learning algorithm. The device's underlying physics and algorithms are designed based on established scientific principles for measuring blood perfusion.
§ 870.2120 Extravascular blood flow probe.
(a)
Identification. An extravascular blood flow probe is an extravascular ultrasonic or electromagnetic probe used in conjunction with a blood flowmeter to measure blood flow in a chamber or vessel.(b)
Classification. Class II (performance standards).