(179 days)
The APERTO Lucent System is an imaging device, and is intended to provide the physician with physiological and clinical information, obtained non invasively and without the use of ionizing radiation. The MR system produces transverse, coronal, sagittal, oblique, and curved cross sectional images that display the internal structure of the head, body, or extremities. The images produced by the MR system reflect the spatial distribution of protons (hydrogen nuclei) exhibiting magnetic resonance. The NMR properties that determine the image appearance are proton density, spin lattice relaxation time (T1), spin spin relaxation time (T2) and flow. When interpreted by a trained physician, these images provide information that can be useful in diagnosis determination.
The APERTO Lucent is a modification of the AIRIS Elite MRI System. The APERTO Lucent has been revised to increase the clinical utility as compared to the AIRIS Elite Magnetic Resonance imaging system. Magnetic Resonance imaging (MRI) is based on the fact that certain atomic nuclei have electromagnetic properties that cause them to act as small spinning bar magnets. The most ubiquitous of these nuclei is hydrogen, which makes it the primary nuclei currently used in magnetic resonance imaging. When placed in a static magnetic field, these nuclei assume a net orientation or alignment with the magnetic field, referred to as a net magnetization vector. The introduction of a short burst of radiofrequency (RF) excitation of a wavelength specific to the magnetic field strength and to the atomic nuclei under consideration can cause a re-orientation of the net magnetization vector. When the RF excitation is removed, the protons relax and return to their original vector. The rate of relaxation is exponential and varies with the character of the proton and its adjacent molecular environment. This re-orientation process is characterized by two exponential relaxation times, called T1 and T2. A RF emission or echo that can be measured accompanies these relaxation events. The emissions are used to develop a representation of the relaxation events in a three dimensional matrix. Spatial localization is encoded into the echoes by varying the RF excitation, applying appropriate magnetic field gradients in the x, y, and z directions, and changing the direction and strength of these gradients. Images depicting the spatial distribution of the NMR characteristics can be reconstructed by using image processing techniques similar to those used in computed tomography.
The provided text describes the FUJIFILM Healthcare Corporation's APERTO Lucent MRI System (K233629) and its substantial equivalence to a predicate device, the AIRIS Elite V4.9 MRI system (K032232).
The document does not describe specific acceptance criteria in terms of numerical thresholds for device performance (e.g., accuracy, sensitivity, specificity). Instead, it focuses on demonstrating substantial equivalence through a comparison of technological characteristics and performance evaluations.
Here's the information extracted from the document:
1. A table of acceptance criteria and the reported device performance
As mentioned, explicit numerical acceptance criteria for performance metrics are not provided. The performance evaluation focuses on demonstrating that the new features and coils perform as intended and produce acceptable image quality for clinical use.
| Acceptance Criteria (Inferred from Rationale Analysis) | Reported Device Performance (Summary from Performance Evaluation) |
|---|---|
| New features perform as intended for diagnostic use. | Test data confirmed that new features perform as intended for diagnostic use. |
| Clinical images from new features and coils have acceptable image quality for clinical use. | A radiologist validated that the clinical images have acceptable image quality for clinical use. |
2. Sample size used for the test set and the data provenance
- Test set sample size: Not explicitly stated. The document refers to "clinical image examples" for new features and coils.
- Data provenance: Not explicitly stated (e.g., country of origin). The study involved "clinical image examples" and validation by a radiologist. It is likely prospective, as it involves evaluating new features and coils.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Number of experts: One radiologist.
- Qualifications of experts: "A radiologist." No further details on years of experience or sub-specialty are provided.
4. Adjudication method for the test set
- Adjudication method: Not applicable/None mentioned. The document states a single radiologist validated the clinical images for acceptable image quality. There is no indication of multiple reviewers or an adjudication process.
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
- MRMC study: No. This submission is for an MRI system, not an AI-assisted diagnostic device. The document does not describe any AI component or human-in-the-loop performance evaluation.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Standalone performance: Not applicable. This is for an MRI system, not an algorithm.
7. The type of ground truth used
- Ground truth: Clinical images were validated for "acceptable image quality for clinical use" by a radiologist. This can be considered a form of expert assessment/consensus (from a single expert in this case) on image quality rather than a definitive "ground truth" for specific diagnoses, as the purpose was to evaluate system functionality and image quality.
8. The sample size for the training set
- Training set sample size: Not applicable. This document describes an MRI system, not an algorithm that undergoes a "training" phase with a dataset. The software development likely involved internal testing and verification, but not in the context of machine learning training data.
9. How the ground truth for the training set was established
- Ground truth for training set: Not applicable (see point 8).
§ 892.1000 Magnetic resonance diagnostic device.
(a)
Identification. A magnetic resonance diagnostic device is intended for general diagnostic use to present images which reflect the spatial distribution and/or magnetic resonance spectra which reflect frequency and distribution of nuclei exhibiting nuclear magnetic resonance. Other physical parameters derived from the images and/or spectra may also be produced. The device includes hydrogen-1 (proton) imaging, sodium-23 imaging, hydrogen-1 spectroscopy, phosphorus-31 spectroscopy, and chemical shift imaging (preserving simultaneous frequency and spatial information).(b)
Classification. Class II (special controls). A magnetic resonance imaging disposable kit intended for use with a magnetic resonance diagnostic device only is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.