(107 days)
This device is indicated to acquire and display cross-sectional volumes of the whole body, to include the head. The Aquilion Precision has the capability to provide volume sets. These volume sets can be used to perform specialized studies, usinq indicated software/hardware, by a trained and qualified physician.
FIRST 3.0 is an iterative reconstruction algorithm intended to reduce exposure dose and improve high contrast spatial resolution for abdomen, pelvis, chest, cardiac, extremities and head applications.
Aquilion Precision (TSX-304A/2) V8.6 with FIRST 3.0 is an ultra-high resolution whole body multi-slice helical CT scanner, consisting of a gantry, couch and a console used for data processing and display. Aquilion Precision incorporates a 160-row, 0.25 mm detector, a 5.7-MHU large-capacity tube, and 0.35 s scanning, enabling wide-range scanning with short scan times to capture cross sectional volume data sets used to perform specialized studies, using indicated software/hardware, by a trained and qualified physician. In addition, the subject device incorporates the latest iterative reconstruction technology, FIRST 3.0, intended to reduce exposure dose while maintaining and/or improving image quality.
The provided document describes the Aquilion Precision (TSX-304A/2) V8.6 with FIRST 3.0, a Computed Tomography (CT) system, and its substantial equivalence to a predicate device. The performance validation focuses heavily on image quality metrics and spatial resolution, particularly for the new HR (High Resolution) and SHR (Super High Resolution) modes and the FIRST 3.0 iterative reconstruction algorithm.
Here's an analysis of the acceptance criteria and the study that proves the device meets them:
1. Table of Acceptance Criteria and the Reported Device Performance:
The document doesn't present a formal table of acceptance criteria with corresponding performance metrics like a typical study design. Instead, it describes various tests and their outcomes, often in qualitative terms comparing the new device to a predicate or describing improvements. However, we can infer some criteria and their met outcomes:
| Metric Category | Acceptance Criteria (Inferred from text) | Reported Device Performance |
|---|---|---|
| Image Quality (General) | Demonstrate equivalent or improved image quality compared to the predicate device and FBP reconstruction, across various standard metrics (CT number accuracy, contrast-to-noise ratio, uniformity, slice sensitivity profile, modulation transfer function, low contrast detectability, standard deviation of noise, noise power spectra). | - The Aquilion Precision in NR mode is "substantially equivalent" to the predicate device for CT image quality metrics. |
- The HR and SHR modes "yield improved high contrast spatial resolution with some tradeoff in noise and LCD relative to NR mode."
- The FIRST algorithm "demonstrates equivalent or improved image quality relative to FBP for all modes." |
| High Contrast Spatial Resolution | Achieve a specific high contrast spatial resolution, particularly with HR mode and FC90 reconstruction. | - A high contrast spatial resolution claim of "up to 46.1 lp/cm based upon the 2% of the MTF of images of a wire test object acquired in HR mode, under the axial scan mode and reconstructed with FC90" is supported initially. - Later, it's stated that "a high contrast spatial resolution claim of up to 49.5 lp/cm, based upon the 2% of the MTF of images of a wire test object acquired in HR mode and reconstructed with FC90, is supported." This suggests an even better performance than initially stated, or a refinement of the measurement. |
| Low Contrast Detectability (LCD) and Dose | Maintain equivalent or reasonable LCD, and ideally demonstrate dose reduction capabilities with FIRST. | - HR and SHR modes "may result in equivalent or a modest increase in X-ray dose as compared to scanning in normal resolution mode (NR)." - "As demonstrated by the performance of FIRST at reduced mA values for standard deviation, MTF, and visual LCD as compared to FBP at higher mA values a qualitative claim of Dose Reduction with FIRST is supported."
- A study on Head and Body MITA-FDA LCD phantoms established baseline LCD (AUC) values and indicated potential trade-offs. |
| Size Discrimination | Demonstrate improved size discrimination. | - A 50% improvement in size discrimination was observed with High Resolution mode compared to Normal Resolution mode at the same dose, using Catphan 10HU contrast rods (4-9mm diameter) in a model observer study. |
| Diagnostic Quality | Produce images of diagnostic quality across various anatomical regions. | - "Representative diagnostic images, reviewed by an American Board Certified Radiologist, including head, chest, abdomen/pelvis, extremity and cardiac exams were also obtained using the subject device which demonstrates that the device produces images of diagnostic quality and; therefore, performs as intended." |
| Substantial Equivalence | Demonstrate substantial equivalence to the predicate device. | - "The Aquilion Precision in NR mode is substantially equivalent to the predicate device." - "NR mode and predicate device images were substantially equivalent." |
2. Sample Size used for the test set and the data provenance:
The document does not explicitly state sample sizes for all tests.
- Spatial Resolution Confirmation: "the MTF results of seven Aquilion Precision systems" were measured. This is a sample size of 7 systems, likely involving phantom data.
- Low Contrast Detectability: "Head and Body MITA-FDA LCD phantoms" were utilized. The number of phantoms or scans is not specified.
- Size Discrimination Performance: "Catphan 10HU contrast rods, 4-9mm in diameter" were used. The number of scans or virtual phantoms is not specified.
- Cadaver and Cardiac Stent Images: "cadaver and cardiac stent images" were provided. The number of cadavers or stents is not specified.
- Diagnostic Quality Images: "Representative diagnostic images... including head, chest, abdomen/pelvis, extremity and cardiac exams" were obtained. The number of cases is not specified.
Data Provenance: Primarily phantom data and some cadaver/stent images appear to be used for the technical performance assessments. The diagnostic quality images were "obtained using the subject device," implying prospective acquisition for the purpose of this submission rather than retrospective data. The location of data acquisition (country of origin) is not specified, but the submission is by Toshiba Medical Systems Corporation, Japan, and Toshiba America Medical Systems, Inc., USA.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
-
Diagnostic Quality Images: "Representative diagnostic images, reviewed by an American Board Certified Radiologist."
- Number of Experts: Singular, "an American Board Certified Radiologist" (implying one).
- Qualifications: "American Board Certified Radiologist." No specific experience level is mentioned (e.g., 10 years of experience).
-
For the phantom-based studies (spatial resolution, LCD, size discrimination), the "ground truth" is typically inherent in the phantom design and physical measurements, rather than established by human experts.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- For the diagnostic quality image review by "an American Board Certified Radiologist," no adjudication method is mentioned, implying it was a single reader assessment.
5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:
- No MRMC comparative effectiveness study involving human readers and AI assistance (FIRST 3.0) is described. The studies primarily focus on the objective image quality metrics of the device itself and its reconstruction algorithms. The "model observer study" for size discrimination is a computational model, not human readers.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, the majority of the image quality evaluations (CT number accuracy, contrast-to-noise ratio, uniformity, slice sensitivity profile, MTF, LCD, etc.) of the FIRST 3.0 algorithm and the new acquisition modes (HR, SHR) are "standalone" performance evaluations. They assess the inherent image characteristics produced by the system and its algorithms using phantoms, independent of a human observer's interpretation in a clinical context.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- Phantom-based studies: The ground truth is the known properties of the phantoms (e.g., known dimensions of rods, known contrast differences, known noise levels).
- Diagnostic Quality Images: The ground truth for this qualitative assessment is the subjective expert opinion of "an American Board Certified Radiologist" that the images are of "diagnostic quality." This is a form of expert opinion, but not "consensus" as only one expert is mentioned.
- No pathology or outcomes data is mentioned as ground truth.
8. The sample size for the training set:
The document does not provide any information about the training set or its sample size. This is typical for submissions focused on the hardware and reconstruction algorithms of a CT scanner, where the "training" (if applicable for AI components) would be part of the algorithm development process, not usually detailed in a 510(k) summary for hardware clearance unless the AI itself is the primary new component. FIRST 3.0 is an iterative reconstruction algorithm, which generally relies on mathematical models and image processing, not necessarily on "training data" in the machine learning sense to learn to identify specific pathologies.
9. How the ground truth for the training set was established:
Not applicable, as no information on a training set or its ground truth establishment is provided.
§ 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.