(165 days)
The SCENARIA View system is indicated to acquire axial volumes of the whole body including the head. Images can be acquired in axial, helical, or dynamic modes. The SCENARIA View system can also be used for interventional needle guidance.
Volume datasets acquired by a SCENARIA View system can be post-processed in the SCENARIA View system to provide additional information. Post-processing capabilities of the SCENARIA View software include, multi-planar reconstruction (MPR), and volume rendering.
Volume datasets acquired by a SCENARIA View system can be transferred to external devices via a DICOM standard interface.
The Low Dose CT Lung Cancer Screening Option for the SCENARIA View system is indicated for using low dose CT for lung cancer screening must be conducted with the established program criteria and protocols that have been approved and published by a governmental body, a professional medical society, and/or Hitachi.
The SCENARIA View is a multi-slice computed tomography system that uses x-ray data to produce cross-sectional images of the body at various angles. The SCENARIA View system uses 128-slice CT technology, where the X-ray tube and detector assemblies are mounted on a frame that rotates continuously around the patient using slip ring technology. The solid-state detector assembly design collects up to 64 slices of data simultaneously. The X-ray sub-system features a high frequency generator, X-ray tube, and collimation system that produces a fan beam X-ray output. The system can operate in a helical (spiral) scan mode where the patient table moves during scanning. As the X-ray tube/detector assembly rotates around the patient, data is collected at multiple angles. The collected data is then reconstructed into cross-sectional images by a high-speed reconstruction sub-system. The images are displayed on a Computer Workstation, stored, printed, and archived as required. The workstation is based on current PC technology using the Windows™ operating system. The SCENARIA View system consists of a Gantry, Operator's Workstation, Patient Table, High-Frequency X-ray Generator, and accessories.
The provided text details the 510(k) premarket notification for the Hitachi SCENARIA View computed tomography x-ray system (K190841). The core of the submission focuses on demonstrating substantial equivalence to a predicate device, the SCENARIA Phase 3 (K150595).
Based on the provided document, here's an analysis of the acceptance criteria and the study that proves the device meets them:
1. A table of acceptance criteria and the reported device performance
The document does not explicitly present a table of quantitative acceptance criteria for the overall device performance in the sense of a new AI/software component with specific clinical performance metrics (e.g., sensitivity, specificity for a diagnostic task). Instead, the acceptance criteria are implicitly tied to demonstrating that the SCENARIA View system performs comparably to its predicate device (SCENARIA Phase 3) and meets established industry standards for CT systems.
The performance characteristics evaluated and reported are typically those for CT imaging systems, rather than AI-specific metrics. The document states:
| Performance Characteristic | Acceptance Criteria (Implicit) | Reported Device Performance |
|---|---|---|
| Clinical Equivalence | Device is substantially equivalent to predicate device (SCENARIA Phase 3) for general CT imaging. | A clinical evaluation comparison was conducted with the SCENARIA View system and the SCENARIA Phase 3 System (K150595) and found to be substantially equivalent. |
| Lung Screening Option | Performance comparable to the predicate evaluated in K180901 (HiMAR, Intelli IPV) for lung cancer screening image quality metrics. | Bench testing was conducted to demonstrate that the SCENARIA View is substantially equivalent to the predicate evaluated in K180901 (in terms of image quality metrics such as CT number accuracy, uniformity, noise, etc...) for the task of lung cancer screening. (This specifically relates to the "Low Dose CT Lung Cancer Screening Option" feature, which references technology cleared in a prior 510(k) K180901). The new iterative reconstruction technique, Intelli IPV, was added. HiMAR (metal artifact reduction technique) has been added which was cleared on the Supria True 64 (K171738). The Lung Screening Option is available on the SCENARIA View, which was cleared in K180901. "Bench testing was conducted to demonstrate that the SCENARIA View is substantially equivalent to the predicate evaluated in K180901 (in terms of image quality metrics such as CT number accuracy, uniformity, noise, etc...) for the task of lung cancer screening." |
| CT System Performance | Compliance with relevant standards and comparable performance to predicate for core CT metrics. | Evaluations were conducted for dose profile, image noise, Modulation Transfer Function (MTF), slice thickness and sensitivity profile, slice plane location, and CT dose index. "These tests and results support inclusion of the Lung Screening Option on the SCENARIA View." The device complies with all applicable requirements for Dose Profile, Noise, Mean CT number and Uniformity, Spatial Resolution, Tomographic Section Thickness and Sensitivity Profile, Tomographic Plane Location, and CT dose index. |
| Clinical Image Quality | Clinical images are diagnostic and meet user needs. | Hitachi has conducted a clinical image study of the head, chest, abdomen, and shoulder that includes an evaluation. In addition, a clinical study was conducted with the Intelli IPV, FBP, and HiMAR features which also includes evaluations. "Therefore, based on a thorough analysis and of the clinical images Hitachi believes the SCENARIA View is diagnostic and meet the user needs." |
| Safety and Effectiveness | Substantially equivalent to predicate in terms of safety and effectiveness. | "Therefore, based on a thorough analysis and comparison of the functions, scientific concepts, physical and performance characteristics, performance comparison and technological characteristics, the proposed SCENARIA View Whole-body X-ray CT System is considered substantially equivalent to the currently marketed predicate device (SCENARIA View Whole-body X-ray CT System (K171738)) in terms of design features, fundamental scientific technology, indications for use, and safety and effectiveness." |
2. Sample size used for the test set and the data provenance
The document mentions "a clinical image study of the head, chest, abdomen, and shoulder" and "a clinical study was conducted with the Intelli IPV, FBP, and HiMAR features". However, it does not specify the sample size (number of patients or images) used in these clinical studies or bench tests for the test set.
The data provenance (e.g., country of origin, retrospective or prospective) is also not specified in the provided text.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
The document states, "Therefore, based on a thorough analysis and of the clinical images Hitachi believes the SCENARIA View is diagnostic and meet the user needs." This implies an expert review, but it does not specify the number of experts, their qualifications, or the methodology they used to establish ground truth or evaluate the "diagnosticity" or "user needs."
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
The document does not specify any adjudication method used for reviewing the clinical images or test sets.
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
The document does not indicate that an MRMC study was performed. The evaluation focuses on the system's inherent performance and its substantial equivalence to a predicate, not on human reader performance with or without AI assistance. The "Intelli IPV" and "HiMAR" features are described as new iterative reconstruction and metal artifact reduction techniques, respectively, which are intrinsic image processing methods of the CT system rather than assistive AI tools for human interpretation in the common sense of an AI CAD (Computer-Aided Detection) or CADx (Computer-Aided Diagnosis) system.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
The entire submission focuses on the performance of the integrated CT system (SCENARIA View) which includes its image acquisition and reconstruction algorithms. Therefore, the "evaluations were conducted for dose profile, image noise, Modulation Transfer Function (MTF), slice thickness and sensitivity profile, slice plane location, and CT dose index" and "bench testing...in terms of image quality metrics such as CT number accuracy, uniformity, noise" can be considered forms of standalone algorithmic performance assessment based on objective phantom and image quality metrics. The "clinical image study" also evaluates the system's output directly.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
For the technical performance evaluations (dose profile, noise, MTF, etc.), the ground truth relies on physical phantom measurements and engineering specifications/standards.
For the "clinical image study," the ground truth implicitly relies on expert subjective assessment of image diagnosticity and ability to meet user needs, "based on a thorough analysis and of the clinical images Hitachi believes the SCENARIA View is diagnostic and meet the user needs." There is no mention of pathology or outcomes data as ground truth.
8. The sample size for the training set
The document does not describe a "training set" in the context of an AI model being developed from scratch. The "Intelli IPV" and "HiMAR" are advanced image reconstruction techniques, which are typically developed using a combination of physics models, empirical data, and potentially machine learning techniques, but the document does not disclose details about any training data or its sample size for these specific features. The device's substantial equivalence is demonstrated against an existing predicate CT system, which implies that its fundamental design and performance are already established, rather than being a de novo AI system requiring a separate training and validation set disclosure in this context.
9. How the ground truth for the training set was established
As no specific training set for a new AI model is described, there's no information on how its ground truth was established. The performance of the image reconstruction algorithms (Intelli IPV, HiMAR) would have been validated against various phantom and clinical datasets to ensure they produce images of acceptable diagnostic quality, likely benchmarked against existing reconstruction methods and assessed by image quality experts. However, the specifics of this process are not detailed in the provided K190841 summary.
§ 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.