(126 days)
Perfusion CT is an application software package that permits cerebral perfusion imaging based on dynamic CT images continuously acquired after the injection of contrast. The package allows visualization of apparent blood flow in brain tissue and pictorially illustrates perfusion related parameters (i.e. relative cerebral blood flow, relative cerebral blood volume, time to peak). By generating images of cerebral blood flow (CBF), cerebral blood volume (CBV), and local bolus timing (i.e. time to peak) from one set of dynamic CT images, Perfusion CT aids the physician in the assessment of the type and extent of cerebral perfusion disturbances. The software package also allows the calculation of mirrored regions of interest and the visual inspection of time density curves.
Perfusion CT is a post-processing software package which runs on an Intel-based PC platform designed to post-process images acquired with SOMATOM CT scanners which meet certain minimal requirements (i.e. Siemens SOMATOM Plus 4, SOMATOM AR.STAR, SOMATOM Classic). It is a package containing evaluation software that supports the evaluation of Dynamic CT data gathered after the injection of a compact bolus of contrast media, where the contrast media acts as a pure intravascular tracer.
Perfusion CT calculates the parameters related to brain perfusion and cerebral blood flow (CBF) using a simple linear relationship between the detected change of signal and the actual concentration of contrast media.
The Perfusion CT Software Package for SOMATOM CT Systems is a post-processing software package that aids physicians in assessing cerebral perfusion disturbances.
Here's an analysis of its acceptance criteria and the supporting study:
1. Table of Acceptance Criteria and Reported Device Performance:
The provided document does not explicitly state quantitative acceptance criteria (e.g., specific sensitivity, specificity, or error rates) or reported device performance metrics (e.g., 90% accuracy). Instead, it focuses on qualitative utility and equivalence to predicate devices.
| Acceptance Criteria (Implied) | Reported (Qualitative) Device Performance |
|---|---|
| Functionality: Calculate and visualize cerebral perfusion parameters (CBF, CBV, time to peak). | The device calculates parameters related to brain perfusion and cerebral blood flow (CBF) using a simple linear relationship. It generates images of CBF, CBV, and local bolus timing from dynamic CT images. The software package also allows the calculation of mirrored regions of interest and the visual inspection of time density curves. |
| Aids in Diagnosis: Useful in assessing type and extent of cerebral perfusion disturbances and diagnosing ischemia. | Clinical studies showed that the Perfusion CT post-processing software package is useful in aiding physicians in diagnosing ischemia. It aids the physician in the assessment of the type and extent of cerebral perfusion disturbances. |
| Substantial Equivalence: Similar technological characteristics and intended use as predicate devices. | The Perfusion CT software package has the same technological characteristics as the predicate Xenon CT and Dynamic CT, except it provides additional post-processing information. Both require contrast medium, rapid image scanning, and physician intervention. |
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size for Test Set: Not specified. The document states "Clinical studies were carried out in Europe to collect cerebral images from individuals with suspected local ischemia." It does not provide the number of patients or cases.
- Data Provenance: Europe. This was a clinical study. It does not specify whether the clinical studies were retrospective or prospective.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications:
Not specified. The document states the software is "useful in aiding physicians in diagnosing ischemia," suggesting physician involvement in assessing the output, but it does not detail how ground truth was established or the number/qualifications of experts involved in the clinical studies.
4. Adjudication Method for the Test Set:
Not specified.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size:
Not specified. The document does not mention an MRMC study or any comparison of human readers with vs. without AI assistance, nor does it provide an effect size.
6. If a Standalone (Algorithm Only) Performance Study Was Done:
The description of the "Clinical Studies and Conclusion" focuses on the software's utility in aiding physicians. There is no explicit mention of a standalone algorithm-only performance study, nor are there quantitative metrics that would typically result from such a study (e.g., sensitivity, specificity, AUC). The device is described as a "post-processing software package" that "aids the physician," implying human-in-the-loop performance.
7. The Type of Ground Truth Used:
Not explicitly stated. Given that the software "aids the physician in the assessment of the type and extent of cerebral perfusion disturbances" and "diagnosing ischemia," it is implied that the ground truth for "diagnosing ischemia" would likely be through clinical diagnosis, potentially supported by other imaging modalities or follow-up clinical outcomes, rather than just expert consensus on the software's output alone. However, the exact reference standard is not detailed.
8. The Sample Size for the Training Set:
Not specified. The document focuses on performance evaluation rather than development.
9. How the Ground Truth for the Training Set Was Established:
Not specified. The document does not provide details about development or training data.
§ 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.