(77 days)
MRCAT imaging is intended to provide the operator with information of tissue properties for radiation attenuation estimation purposes in photon external beam radiotherapy treatment planning.
Indications for use:
MRCAT Brain is indicated for radiotherapy treatment planning for primary and metastatic brain tumor patients.
MRCAT brain is a software application to Ingenia, Ingenia Ambition, and Ingenia Elition MR systems. MRCAT brain is available to the customer as an option to Ingenia MR-RT package, which is a set of accessories for Ingenia systems.
Automated generation of MRCAT images takes place at the MR console of Ingenia. The embedded image post-processing runs in the background parallel to image acquisition. MRCAT algorithm enables automatic tissue characterization: Bones are segmented from mDixon in-phase and water images using machine learning based segmentation. Body outline is segmented using in-phase and water images. Tissues are then assigned a continuum of HU values depending on the fat and water intensities of the voxels. The HU assignment provides MRCAT images with CT-like density information.
The document provides information on the Philips Medical Systems MR Finland MRCAT Brain device, which is a software add-on for MR systems intended for radiotherapy treatment planning for primary and metastatic brain tumor patients.
Here's an analysis of the acceptance criteria and supporting studies based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (MRC-Brain) | Reported Device Performance |
|---|---|
| Dose Accuracy: |
- Simulated dose based on MRCAT Brain images shall not differ in 95% of the indicated patients (gamma analysis criterion 2%/2mm realized in 98% of voxels within the PTV or exceeding 75% of the maximum dose) when compared with CT-based plan.
- The average simulated dose based on MRCAT Brain shall not deviate more than 5% or 1 Gy, whichever is greater, in 99% of the indicated patients in the volume of sensitive organs when compared with CT based plan. | The robustness of the MRCAT brain algorithm for producing equivalent dose plans to CT using gamma analysis with criterion of 1%/1mm is shown by post-processing MRCAT images from patients, and calculating dose using the MRCAT images. (Though the reported criterion is 1%/1mm, the acceptance criterion specifically mentioned 2%/2mm, implying the device met or exceeded this with the 1%/1mm demonstration). The document states that MRCAT brain met the acceptance criteria and is adequate for its intended use. |
| Geometric Accuracy: - MRCAT accuracy: ± 1 mm accuracy for a 200 mm diameter sphere.
- MRCAT accuracy: ± 5 mm accuracy for a 500 mm diameter sphere (limited in the bore direction by +/- 160 mm from the z=0 mm plane). | The document states "No significant difference" in geometric accuracy when comparing MRCAT Brain to MRCAT Pelvis, which has the same geometric accuracy criteria. It also generally states that "Non Clinical verification and or validation test results demonstrate that the MRCAT brain... Meets the acceptance criteria and is adequate for its intended use." |
| Compliance with Standards: - ANSI/AAMI ES60601-1: 2012
- IEC 60601-1-6:2010
- IEC 60601-2-33:2015
- IEC 62304:2016
- IEC 62366-1:2015
- ISO 14971:2007 (A comprehensive list of international and FDA-recognized consensus standards for medical electrical equipment, usability, safety of MR equipment, medical device software lifecycle processes, usability engineering, and risk management). | "The MRCAT brain complies with the following international and FDA-recognized consensus standards." and "Non Clinical verification and or validation test results demonstrate that the MRCAT brain: Complies with the aforementioned international and FDA-recognized consensus standards." |
| MRCAT image generation correctness: - Sanity checks to ensure imaging field of view is correctly positioned.
- Sanity checks to ensure MRCAT body outline matches that of the MR. | "The generated MRCAT images are checked for correctness to ensure validity of the generated MRCAT for radiation treatment. The sanity checks ensure that the imaging field of view has been positioned correctly and that the MRCAT body outline matches that of the MR." The overall conclusion on non-clinical tests also states: "met the acceptance criteria and is adequate for this intended use." |
| HU value calibration: - The HU values for the MRCAT Brain are calibrated using registered CT images from several sites. | "The HU values for the MRCAT brain are calibrated using registered CT images." and "The overall conclusion on non-clinical tests also states: "met the acceptance criteria and is adequate for this intended use." |
The Study Proving Device Meets Acceptance Criteria:
The document describes a "Summary of Non-Clinical Performance Data" and a "Summary of Clinical Data" to support the device's substantial equivalence and adherence to acceptance criteria.
2. Sample Size Used for the Test Set and Data Provenance:
The document mentions that the robustness of the MRCAT brain algorithm for producing equivalent dose plans to CT using gamma analysis was shown by post-processing MRCAT images from patients. However, it does not specify the exact sample size used for this patient data (test set) or the country of origin/provenance (retrospective or prospective) of this patient data.
3. Number of Experts Used to Establish Ground Truth and Qualifications:
The document does not provide information regarding the number of experts used to establish ground truth or their specific qualifications for the test set.
4. Adjudication Method:
The document does not specify any adjudication method (e.g., 2+1, 3+1, none) used for establishing ground truth in the test set.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
The document makes no mention of a Multi-Reader Multi-Case (MRMC) comparative effectiveness study being done. The focus is on the device's technical performance in generating comparable dose plans to CT, not on human reader performance with or without AI assistance.
6. Standalone (Algorithm Only) Performance:
Yes, a standalone performance was done. The dose accuracy and geometric accuracy criteria, as well as the comparison to CT-based plans, are direct assessments of the algorithm's performance without human intervention in the primary image generation and initial dose calculation. The "robustness of the MRCAT brain algorithm" and its ability to produce "equivalent dose plans to CT" describe standalone performance.
7. Type of Ground Truth Used:
The primary ground truth used for assessing the device's performance, particularly dose accuracy and HU value calibration, is registered CT images and CT-based treatment plans. The comparisons are made against these CT data, which are considered the established standard for radiation attenuation estimation in radiotherapy planning.
8. Sample Size for the Training Set:
The document states that the Convolutional Neural Network (CNN) used in MRCAT image generation is "trained using matched pairs of CT and MRCAT source images." However, the exact sample size used for the training set is not specified.
9. How the Ground Truth for the Training Set Was Established:
The ground truth for the training set was established using "matched pairs of CT and MRCAT source images." This implies that CT images served as the reference or ground truth against which the MRCAT source images were processed and the CNN was trained to generate CT-like density information (HU values).
§ 892.5050 Medical charged-particle radiation therapy system.
(a)
Identification. A medical charged-particle radiation therapy system is a device that produces by acceleration high energy charged particles (e.g., electrons and protons) intended for use in radiation therapy. This generic type of device may include signal analysis and display equipment, patient and equipment supports, treatment planning computer programs, component parts, and accessories.(b)
Classification. Class II. When intended for use as a quality control system, the film dosimetry system (film scanning system) included as an accessory to the device described in paragraph (a) of this section, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.