(244 days)
The Philips Medical Systems' Brain Perfusion is a post processing software application intended to assist with the evaluation of an area of interest, to generate qualitative information about changes in image intensity over time. It supports the analysis of dynamic/serial CT after injection of contrast agent, by calculating the parameters related to brain perfusion and displays the results as a composite (single image that is calculated from a set of time course images at a single location) images.
The Philips Medical Systems' Brain Perfusion (BP) application is a post processing software to be used as an advanced visualization application of CT brain perfusion images. The BP application is used to support the analysis of dynamic and/or serial CT brain images after injection of contrast. The BP application is intended to assist with the evaluation of an area of interest, and to generate qualitative and quantitative information about changes in image intensity over time. The BP application presents the results as a composite (single image that is calculated from a set of time course images at a single location) images and provides perfusion parameters maps. The following parameters related to brain perfusion are calculated: Cerebral Blood Flow (CBF), Cerebral Blood Volume (CBV), local bolus timing (Time to Peak (TTP)) and Mean Transit Time (MTT) and supports processing and visualization of Permeability maps.
The provided document describes the Philips Medical Systems' Brain Perfusion (BP) application, a post-processing software for CT brain perfusion images. It aims to assist in evaluating areas of interest and generating qualitative and quantitative information about changes in image intensity over time, particularly for cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and permeability maps.
Here's a breakdown of the acceptance criteria and study information:
1. Table of Acceptance Criteria and Reported Device Performance
The document describes the performance evaluation of the device as follows:
| Acceptance Criteria Category | Specific Criteria | Reported Device Performance |
|---|---|---|
| Perfusion Parameters | Comparison with predicate device according to pre-set acceptance criteria (assessment of correlation and agreement according to regression analysis characteristics). | The performance of the perfusion parameters (CBF, CBV, MTT, TTP) implemented in the Brain Perfusion application has been demonstrated by meeting the acceptance criteria in comparison with the predicate device using a synthetic phantom. |
| Permeability Maps (Technical Validation) | Determine the appropriate permeability method (quantitative validation using synthetic simulated data). | Patlak analysis was found to be most appropriate and was implemented in the BP application for permeability maps. |
| Permeability Maps (Pre-clinical Validation) | Successful identification of regions of increased permeability that correspond to ground truth permeability markers on histology for imaging during occlusion and after reperfusion in rats. | The implemented permeability method has successfully identified regions of increased permeability that correspond to ground truth permeability markers on histology. External evaluations further demonstrated that areas of increased permeability measured in-vivo by imaging coincide with BBB disruption and hemorrhage area observed on gold standard histology. |
| User Needs and Intended Use Validation | Physicians evaluate whether features and workflows fulfill user needs and enable the intended use of the application, based on specific scores. | Based on scores provided by physicians, it has been established that the device meets the users' needs and fulfills its intended use. |
| Human Factors | Minimize use errors and reduce use-associated risks based on formative and summative usability validation testing and usability engineering file analysis. | The Brain Perfusion application was found to be safe and effective for the intended use, intended users, and intended use environments. |
Note: The document does not provide specific numerical thresholds or detailed statistical results for the "pre-set acceptance criteria" or "correlation and agreement according to regression analysis characteristics" beyond stating that the criteria were met.
2. Sample Size Used for the Test Set and Data Provenance
- Perfusion Parameters (Comparison with Predicate): The test set for perfusion parameters involved a synthetic phantom. The sample size (number of phantom simulations or data points generated) is not specified. The data provenance is synthetic/simulated.
- Permeability Maps (Pre-clinical Validation): The test set involved rats imaged during occlusion and after reperfusion. The number of rats or cases is not specified. The data provenance is described as "in-vivo" (animal model).
- User Validation: "Physicians evaluated..." The number of physicians and cases used for this evaluation is not specified. Data provenance is implied to be from their evaluation of the device's features and workflows.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
- Perfusion Parameters (Synthetic Phantom): The ground truth for the synthetic phantom is inherent in its design and the known parameters it simulates. No external experts are mentioned for establishing ground truth for this segment.
- Permeability Maps (Pre-clinical Validation): Histology was used to determine the ground truth for the status of brain tissue and BBB permeability in rats. The number of experts interpreting the histology, or their qualifications, are not specified.
- User Validation: The ground truth is effectively the "user needs" and "intended use" as evaluated by "physicians." The number of physicians is not specified, nor are their specific qualifications (e.g., number of years of experience in radiology/neurology).
4. Adjudication Method for the Test Set
The document does not explicitly describe an adjudication method (like 2+1, 3+1, etc.) for any of the test sets.
- For the perfusion parameters, it was a comparison against data from a synthetic phantom and the predicate device.
- For permeability maps, it was a comparison against histology as ground truth.
- For user validation, it was based on scores provided by physicians.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
The document does not mention a multi-reader multi-case (MRMC) comparative effectiveness study to assess the improvement of human readers with AI vs. without AI assistance. The performance evaluation focused on the device's standalone output and its comparison with a predicate device and ground truth.
6. Standalone (Algorithm Only) Performance Study
Yes, a standalone performance study was done.
- The "Performance evaluation testing was conducted in order to validate the proper function of the perfusion and permeability parametric maps."
- "The subject device's perfusion parameters performance was evaluated in comparison with the predicate device according to pre-set acceptance criteria (assessment of correlation and agreement according to regression analysis characteristics). The perfusion parameters values were generated by utilizing a synthetic phantom." This assesses the algorithm's performance in generating perfusion maps.
- "Internal performance evaluation of the Permeability maps calculation was conducted in two phases. In the technical validation, a quantitative validation using synthetic simulated data was performed... The implemented permeability method has successfully identified regions of increased permeability that correspond to ground truth permeability markers on histology." This assesses the algorithm's ability to calculate and identify permeability.
These evaluations focus on the algorithm's outputs and their accuracy against known values or ground truth, without a human-in-the-loop component.
7. Type of Ground Truth Used
- Perfusion Parameters: The ground truth was based on the known parameters of a synthetic phantom and comparison with the outputs of a predicate device.
- Permeability Maps: The ground truth was established using histology from rats.
- User Validation: The ground truth was implicit in the user needs and intended use, assessed by physicians' evaluations.
8. Sample Size for the Training Set
The document does not specify the sample size used for the training set. It primarily discusses the validation and verification processes.
9. How the Ground Truth for the Training Set Was Established
The document does not specify how the ground truth for any potential training set was established. It focuses on the evaluation of the final product.
§ 892.1750 Computed tomography x-ray system.
(a)
Identification. A computed tomography x-ray system is a diagnostic x-ray system intended to produce cross-sectional images of the body by computer reconstruction of x-ray transmission data from the same axial plane taken at different angles. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II.