(157 days)
The purpose of the ATD-T is to provide interface and support functions to allow the use of Medrad disposable endorectal coils with the GEMS Signa 1.5 Tesla MRI Scanner System and Torso Array Coil. The use of the ATD-T is a requirement whenever MR imaging is to be performed using the GEMS Signa 1.5 Tesla MRI System with the Torso Array Coil and any of the Medrad family of disposable endorectal coils. Use of the ATD-T is indicated with all 1.5 Tesla Endorectal Coils.
The Medrad Magnetic Resonance Endorectal Imaging System consists of a disposable, receive only endorectal coil for MR imaging of the male prostate gland and associated anatomy, or other target region of interest, including the cervix and colon. The Medrad ATD-T provides the interface, decoupling, and support functions required to successfully operate the endorectal coils with the GEMS Signa MRI Scanner System with Phased Array capability, and the GEMS Torso Array Coil operating at 1.5 Tesla. The ATD-T consists of two electronic devices, a printed circuit board installed in an Input Port housing attached to the Torso Array Coil posterior cable, and an external unit placed between the Torso Array Coil output cable and the system Phased Array Coil Port. This hardware is intended for repeated use with suitable Medrad disposable MRI Endorectal Coils. The ATD-T sets the tuning and impedance matching of a nominal endorectal coil to the nominal system Larmour frequency, 63.87 MHz for the GEMS Signa 1.5 Tesla MRI System.
The electronic components required to provide effective decoupling disposable endorectal coils resonant response from the MRI RF excitation field during the transmit portion of the MR imaging pulse sequence are included in the ATD-T Input Port Unit.
The ATD-T External Unit combines the signal from the two posterior coil elements of the Torso Array coil to drive a single Phased Array Coil Port, making one Port available for the output of the endorectal coil. It includes internally selectable circuitry to enable it to be used with either the current version of the GEMS/Gore Torso Array Coil [using PA Ports 3, 4, 5, and 6], or the future version designed to meet IEC-601 First Fault detection conditions [using PA Ports 2, 4, 5, and 7].
The ATD-T is designed as a durable item with an expected life of at least three thousand procedures, equivalent to at least five years of service. The specific application of this version of the ATD-T involves MR imaging at 1.5 Tesla, using a Medrad disposable endorectal coil, and a GEMS Signa 1.5 Tesla MRI System including the GEMS Phased Array feature and the Torso Array Coil.
Here's a breakdown of the acceptance criteria and study information for the Medrad 1.5T ATD-T, based on the provided document:
Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Equivalent or Increased Signal to Noise Ratio (SNR) compared to the predicate device. | The Medrad 1.5T ATD-T and the predicate GE ATD-III were evaluated using a loaded phantom to determine SNR. The coils were evaluated using the same scan parameters to produce identical images. The results were compared to "verify the equivalent or increased SNR of the proposed coil." This implies the Medrad 1.5T ATD-T met or exceeded the SNR of the predicate device. |
| No adverse effect on image performance of Medrad Endorectal Coils, GE Torso Array, or the GE MRI System. | "Medrad has demonstrated with Laboratory testing that the proposed Medrad 1.5T ATD-T does not affect the image performance of the Medrad Endorectal Coils, the GE Torso Array, or the GE MRI System. No claims for enhanced images are made herein." |
| Durability: Expected life of at least three thousand procedures, equivalent to at least five years of service. | Extensive "durability" testing was conducted to substantiate claims. While a specific performance result (e.g., "device lasted X procedures") is not provided, the conclusion states that testing was conducted "to substantiate the claims of the proposed device," implying this criterion was met. |
| Safety: General safety. | Extensive "safety" testing was conducted. While no specific performance metrics are given, the conclusion states that testing verified the device is "substantially equivalent to the predicate device," which includes safety aspects. |
| Verification (general functionality) | Extensive "verification" testing was conducted to substantiate claims and verify substantial equivalence. |
| Image Uniformity Testing: Not Applicable | "Not Applicable. No uniformity claims are made for this device." |
| SAR (Specific Absorption Rate): Not Applicable | "SAR: Not applicable." |
Study Details
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Sample Size used for the test set and the data provenance:
- Sample Size: Not explicitly stated as a number of patients or images. The SNR testing was conducted using a "loaded phantom." The "Laboratory testing" for image performance also suggests a controlled environment rather than human subject data. Therefore, the "test set" primarily refers to evaluations on physical equipment and phantoms.
- Data Provenance: The document implies laboratory and bench testing rather than human clinical data. This would suggest the data is from Medrad's internal testing facilities (likely in the US, given the company's address). The data is retrospective in the sense that it was collected prior to the 510(k) submission.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- This information is not provided in the document. The testing described (SNR with phantoms, image performance evaluation) doesn't inherently require expert readers for ground truth in the way a diagnostic algorithm for disease detection would. The ground truth for SNR is objective measurement from the MR scanner, and for image performance, it's evaluated against expected image quality parameters.
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Adjudication method for the test set:
- Not applicable/Not provided. Given the nature of the testing (phantom-based SNR and image performance), there's no mention or indication of an adjudication method typical for diagnostic device studies involving human interpretation.
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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. A MRMC comparative effectiveness study was not performed. This device is an accessory (an interface device for an MRI coil), not an AI diagnostic algorithm. Therefore, there's no "human readers improve with AI vs without AI assistance" component.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, in essence. The performance testing described (SNR with phantoms, image performance without clinical claims) represents the standalone performance of the hardware device and its ability to interface and maintain image quality, independent of human interpretation. It is a hardware component, not an algorithm, so "algorithm only" performance is not strictly applicable, but the tests performed were of the device itself.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The ground truth for the SNR evaluation was objective quantitative measurement obtained from the MRI scanner using a phantom, following NEMA Standard No. 6.
- The ground truth for "image performance" (to ensure it did not affect existing image quality) would have been comparison to baseline image quality parameters or expectations, likely established through the MRI system's specifications and the performance of the predicate device.
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The sample size for the training set:
- Not applicable/Not provided. This is a hardware interface device, not a machine learning or AI algorithm. Therefore, there is no "training set" in the context of AI development. Development and engineering likely involved various test samples (e.g., electronic components, prototype PCBs, endorectal coils) but not a data-based training set.
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How the ground truth for the training set was established:
- Not applicable. As a hardware device, there is no "training set" or corresponding ground truth in the AI sense. Ground truth for its design and verification would rely on engineering specifications, electrical impedance matching principles, MRI physics, and established testing standards.
§ 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.