(90 days)
Anatomical region : Extremities Nuclei excited Diagnostic uses : 2D imaging, 3D imaging
Model Name : Ortho 8000 Isotope : Proton Imaging Model Characteristics Magnet Permanent 0.17 Tesla Static Field strength +/-20ppm over 16cm DSV Homogeneity RF Coil Types - Leg coil l Transmit/receive coil for knee/foot/ankle/leg/elbow 15 cm Diameter x 8 cm Length - 2. Arm Coil Transmit/receive coil for hand/wrist/forearm 10 cm Diameter x 6 cm Length - 3 18 cm Loop Coil Transmit/receive coil for general purpose use - 4 12 cm Loop Transmit/receive coil for general purpose use Data Acquisition Modes Phase and frequency encoding to sample k-space 2D Multiple Slice 2D Multiple Slice, Multiple Echo 3D Multiple Slice Pulse Sequences Spin echo Gradient (Field) echo Inversion recovery Dynamic imaging These sequences can provide T1 weighted, T2 weighted, T2* weighted images Reconstruction Techniques 2D Fourier Transform 3D Fourier Transform Type of Installation Fixed Site Slice Selection Methods Selective excitation in the presence of a field gradient Phase encoding for 3D Display Matrix 256 x 256 1 - 4 Simultaneous Images Acquisition Matrix 64 - 256 in steps of 1 for the phase encoding direction 256 in the frequency encoding direction Image Acquisition Time 2D - Repeat Time x Number of Excitations x Number of Phase Encoding Steps 3D - Repeat Time x Number of Excitations x Number of Phase Encoding Steps x Number of Slice Encoding Steps Image Pre and Post Processing Magnitude Value Pixel Value Horizontal/Vertical Line Profiles Spatial Filtering - Hamming Filter in Frequency and Phase Directions Number of Slices, Range and Increment 2D - 1-16 in steps of 1 3D - 16 slice only Slice Orientation Transverse (Axial) Sagittal Coronal Oblique 3 Orthogonal Plane Scouts Interslice Spacing, minimum, maximum and increment 0 mm, 10mm, Increment 1 mm
This analysis is based on the provided FDA 510K Summary for the INNER VISION MRI Ortho 8000 device.
Acceptance Criteria and Reported Device Performance
1. Table of Acceptance Criteria and Reported Device Performance:
The document primarily outlines specifications rather than explicit "acceptance criteria" in the sense of predefined thresholds for clinical utility. However, the "Imaging Performance" section (Section 3.C) provides detailed technical specifications for the device that implicitly serve as acceptance criteria for its functional performance. The device's performance is then reported against these specifications in Section 7. "CONCLUSIONS FROM TESTING."
| Performance Metric | Acceptance Criteria (Specification) | Reported Device Performance |
|---|---|---|
| Signal-to-Noise Ratio (SNR) | ||
| Leg Coil | SNR > 20:1 (Transverse, Sagittal, Coronal, Oblique) | "The signal to noise ratio values were consistently above the target specification values for each of the coils with the parameters measured above." (Section 7) |
| Arm Coil | SNR > 40:1 (Transverse, Sagittal, Coronal) | "The signal to noise ratio values were consistently above the target specification values for each of the coils with the parameters measured above." (Section 7) |
| 18 cm Loop Coil | SNR > 30:1 (Transverse, Sagittal, Coronal) | "The signal to noise ratio values were consistently above the target specification values for each of the coils with the parameters measured above." (Section 7) |
| 12 cm Loop Coil | SNR > 30:1 (Transverse, Sagittal*, Coronal) | "The signal to noise ratio values were consistently above the target specification values for each of the coils with the parameters measured above." (Section 7) |
| Uniformity | ||
| All Coils | Non-Uniformity 80% of material within Full Width Half Maximum. | No direct quantitative report comparing to the >80% specification is provided in Section 7, but it generally implies compliance. "The measurement methods used are based on calibration using a well characterised physical object and provide direct evidence of the performance characteristics of the scanner." (Section 7) |
| Slice Thickness (Arm coil) | 2-10 mm in 1mm increments (Transverse, Sagittal, Coronal) | "Slice thickness, spacing and gap were all within the quoted specifications using the frequency encoding method." (Section 7) |
| Slice Spacing (Arm coil) | 0-10 mm in 1mm increments (Transverse, Sagittal, Coronal) | "Slice thickness, spacing and gap were all within the quoted specifications using the frequency encoding method." (Section 7) |
| Spatial Resolution (Leg Coil) | Maximum theoretical pixel resolution = 0.31 mm; 1 mm test rods resolved in all 4 quadrants | "1 mm test rods resolved in all 4 quadrants Transverse, Sagittal. Coronal." (Section 3.C.e) - This implies the device met this specifically stated resolution for the Leg Coil. The conclusion states, "the InnerVision MRI extremity scanner meets the performance specifications claimed." (Section 7) |
Study Details
The provided document describes a technical performance verification study rather than a clinical trial directly assessing diagnostic accuracy or human reader performance.
2. Sample size used for the test set and the data provenance:
- Sample Size (Test Set): The document does not specify a "sample size" in terms of clinical cases or individual patients. Instead, the testing was performed using a phantom. The phantom used is described as a "well characterised physical object" (Section 7) and described in more detail in Section 3.C as a "Specification Volume 75mm length x 75 mm diameter Cylinder," with details on "1mm test rods resolved in all 4 quadrants."
- Data Provenance: The technical and imaging performance tests were conducted at Middlesex Hospital, London, England. The study period was February - July 1996.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of Experts: This information is not provided.
- Qualifications of Experts: This information is not provided.
- Note: Given it's a technical performance study using a phantom, the "ground truth" is typically established by physical measurements of the phantom and known engineering principles, not via expert consensus on clinical images.
4. Adjudication method for the test set:
- Adjudication Method: Not applicable/Not described. The ground truth for technical performance metrics (SNR, uniformity, distortion, slice thickness) on a phantom is based on the known properties of the phantom and direct physical measurements, not on a human adjudication process for diagnostic interpretations.
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, an MRMC comparative effectiveness study was not done. This document describes the technical performance and safety of an MRI device itself, not an AI-assisted diagnostic tool.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Standalone Performance: No, this study is of an MRI scanner, not an AI algorithm. Therefore, "standalone (algorithm only)" is not applicable.
7. The type of ground truth used:
- The ground truth for the technical performance tests was established by physical properties of a well-characterized phantom and direct physical measurements (Section 7).
8. The sample size for the training set:
- Sample Size (Training Set): Not applicable. This document describes the performance evaluation of an MRI system, not a machine learning model, so there is no "training set."
9. How the ground truth for the training set was established:
- Not applicable. As there is no training set for a machine learning model, the establishment of ground truth for a training set is not relevant to this document.
§ 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.