(211 days)
The cfrQuant coronary flow reserve (CFR) quantification software quantifies blood flow in the myocardial wall of the heart's left ventricle based on positron emission tomography (PET) images of radionuclide tracer distribution.
The product is intended for use by trained professionals, such as nuclear technicians and nuclear medicine or nuclear cardiology physicians. The clinician remains ultimately responsible for the final assessment and diagnosis based on standard practices and visual interpretation of all PET data.
The software accepts cardiac PET images of either N-13 ammonia or Rb-82 tracer uptake during two physiologic states: baseline (rest) and increased blood flow (stress). A mathematical model computes absolute myocardial perfusion (flow per mass of tissue, or cc/min/gm) at rest and stress. The ratio of stress-to-rest flow is termed the coronary flow reserve (CFR). Visual displays of absolute flow and CFR as well as their numeric quantification are presented to aid diagnostic interpretation of myocardial PET images.
The coronary flow reserve (CFR) quantification (cfrQuant) system is a software package intended for use by nuclear medicine and nuclear cardiology physicians and technologists to perform clinical quantitative analysis on cardiac positron emission tomography (PET) image data. Archiving of output data will be supported for clinical diagnostics, quality control, and research.
cfrQuant calculates absolute myocardial blood flow in cc/min/g using a twodimensional topographical map of PET tracer uptake and an integrated arterial input value. Absolute myocardial flow is calculated from a mathematical flow model validated using microspheres in animals (see Yoshida, Mullani and Gould in J Nuc Med 37:1701, 1996).
To compute CFR, three inputs are required: integrated arterial activity in the early part after bolus injection, average myocardial activity in the late part after bolus injection, and correction factors for partial volume effects of the PET scanner. The first number comes from a region of interest (ROI) drawn in the thoracic aorta or left atrium on images taken soon after radionuclide bolus administration. The second number comes from the topographic maps of myocardial uptake produced by the Positron CARDIAC software. The third number varies by PET camera and will be initialized in a user preference file.
Here's a breakdown of the acceptance criteria and study information for the cfrQuant device, based on the provided text. Unfortunately, the provided document is a 510(k) summary and FDA letter, which primarily focuses on regulatory approval and substantial equivalence to predicate devices, rather than detailed performance studies and acceptance criteria as one might find in a full clinical study report. Therefore, some information is not explicitly stated or is inferred.
1. Table of Acceptance Criteria and Reported Device Performance
The 510(k) summary does not explicitly state quantitative acceptance criteria or a formal table of reported device performance metrics against those criteria. The device is cleared based on demonstrating substantial equivalence to predicate devices. The core "performance" is its ability to quantify absolute myocardial blood flow and coronary flow reserve (CFR) using established mathematical models.
However, the technology's validation is mentioned:
- Acceptance Criteria (Inferred from description): The software should accurately calculate absolute myocardial blood flow in cc/min/g and coronary flow reserve (CFR) based on PET tracer uptake and arterial input, using a mathematical flow model validated with microspheres.
- Reported Device Performance:
- "cfrQuant calculates absolute myocardial blood flow in cc/min/g using a two-dimensional topographical map of PET tracer uptake and an integrated arterial input value."
- "Absolute myocardial flow is calculated from a mathematical flow model validated using microspheres in animals (see Yoshida, Mullani and Gould in J Nuc Med 37:1701, 1996)."
- "The ratio of stress-to-rest flow is termed the coronary flow reserve (CFR). Visual displays of absolute flow and CFR as well as their numeric quantification are presented to aid diagnostic interpretation of myocardial PET images."
2. Sample Size Used for the Test Set and Data Provenance
The provided document does not specify a distinct "test set" sample size or data provenance (country, retrospective/prospective) for a performance validation study of cfrQuant itself.
The primary evidence referenced for the underlying mathematical model's validity is a publication: "Yoshida, Mullani and Gould in J Nuc Med 37:1701, 1996." This publication describes validation using microspheres in animals, not human test sets for the cfrQuant software.
For 510(k) submissions, the focus is often on demonstrating equivalency to existing cleared devices rather than extensive new clinical performance studies, especially for software that implements a known scientific model.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
Given the lack of a specific "test set" described for cfrQuant's performance validation, this information is not applicable or not provided. The ground truth for the underlying mathematical model's validation was established in animals using microspheres, which is a direct physiological measurement, rather than human expert consensus.
4. Adjudication Method for the Test Set
Not applicable as no specific human-read test set and adjudication process are described for cfrQuant's performance validation.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, the document does not mention an MRMC comparative effectiveness study where human readers' performance with and without AI assistance was evaluated for cfrQuant.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
The device is inherently an "algorithm only" tool for quantification. Its performance, as described, is the output of its calculations. The reference to the "mathematical flow model validated using microspheres in animals" (Yoshida, Mullani and Gould, 1996) serves as the standalone validation of the core algorithm's underlying principle.
The cfrQuant system is described as a "software package intended for use by nuclear medicine and nuclear cardiology physicians and technologists to perform clinical quantitative analysis." While physicians use the output, the calculation itself is standalone.
7. The Type of Ground Truth Used
For the underlying mathematical model that cfrQuant implements, the ground truth was microspheres in animals. This is a direct physiological measurement of blood flow, considered a gold standard in such preclinical studies.
8. The Sample Size for the Training Set
Not applicable or not provided. This device is based on a pre-established mathematical model, not a machine learning model that requires a "training set" in the conventional sense. The "training" of the model itself would have occurred during its initial development and validation, as referenced by the Yoshida et al. publication.
9. How the Ground Truth for the Training Set Was Established
Not applicable in the typical machine learning sense. The ground truth for the validation of the mathematical model was established using microsphere injection in animals with subsequent direct physiological measurement of blood flow. This provides a direct, highly accurate "ground truth" for the flow calculations made by the model.
§ 892.1200 Emission computed tomography system.
(a)
Identification. An emission computed tomography system is a device intended to detect the location and distribution of gamma ray- and positron-emitting radionuclides in the body and produce cross-sectional images through computer reconstruction of the data. This generic type of device may include signal analysis and display equipment, patient and equipment supports, radionuclide anatomical markers, component parts, and accessories.(b)
Classification. Class II.