Multi-Coil Quality Assurance (MCQA) Tool

Prerequisites

Overview

The Multi-Coil Quality Assurance (MCQA) tool simplifies data acquisition and SNR analysis for surface coils. It helps detect dead coil elements, and helps develop improved integrated signal-to-noise ratio (ISNR) specifications for all multi-coils, independent of scanner instabilities.

The MCQA tool does not rely on ROI placement like other SNR tools in the past. Instead, it chooses slice locations based on coil geometry, acquires one spin echo image, and turns off RF to gather a noise image. The noise mean of the 2D noise-only image is subtracted from the 2D intermediate image.

The summed signal (2D intermediate image minus noise mean) is calculated, and this signal is divided by the standard deviation of the noise for all pixels of the noise-only image, resulting in the ISNR.

The summed signal (2D intermediate image minus noise mean) is calculated, and then the signal is divided by the Standard Deviation of the Noise of all pixels of the noise-only-image to give the ISNR.

    1 MCQA Tool

    All coil-related tests must be run on a system that is well calibrated and passes all system tests. The system should have passed Install In Spec (IIS), especially white pixel, correlated noise, and Multi-Coil Receive (MCR) tests.

    Procedure

    1. From the Common Service Desktop, open the Service Browser, select Image Quality, Multi-Coil QA Tool, and Click here to start this tool.
    2. At startup, the MCQA tool tries to identify the coil connected to the system.

      • If successful, the tool automatically lists the connected coil in the Current Coil field.

        The Current Coil field is blank when more than one supported coil is connected. In this case, the Current Coil field provides an active drop-down list. Select the appropriate coil based on the coil on which QA test is to be performed.

      • If more than one supported coil is connected, the Current Coil field provides an active drop-down list, select the appropriate coil based on the coil on which QA test is to be performed.

      • If the coil is not recognized, a message displays indicating that the coil needs to be configured.

    3. If a recognized coil can use either the legacy phantom set or the unified phantom set, a prompt appears to select the correct phantom set. Click OK to continue.
    4. The Phantom Set field varies depending upon the coil that is plugged into the system.

      • If the Phantom Set field provides an active drop-down list, select the phantom based on the phantoms used during setup for the MCQA test as described in the coil’s service manual.

      • If the Phantom Set field is grayed out (unselectable), the tool has automatically selected the phantom set based on the coil used.

    5. Enter the serial number of the coil being tested in the Coil Serial Number field.
    6. Click Start to begin the automated test.
    7. At the phantom selection prompt, select Yes to continue.
    8. At the phantom placement and coil landmarking prompt, verify that the landmark was set correctly and no air bubbles exist in the phantom, then click Yes to continue.
    9. At the phantom placement and coil landmarking prompt, verify that the landmark was set correctly and no air bubbles exist in the phantom, then click Yes to continue.

      While the tool is running, the status window is continuously updated with information on what the tool is doing. A time bar is displayed showing approximate total test time, elapsed time, and percent complete.

      Depending on the number of test locations (coil complexity), the test may take from three to twenty minutes.

      When the test is completed, test results are displayed. The Pass/Fail status field says PASS if all coil elements are functioning properly.

    10. If any coil element displays FAIL, call the GE Service Representative for coil repair.

      The MCQA tool displays FAIL for reasons, including, but not limited to:

      • Bad coil element

      • Incorrect phantom used for testing

      • Incorrect positioning or placement of the phantom

    11. If the MCQA test fails, run the Multi-Coil Receive (MCR) tool to validate the receive chain function.

    2 Finalization

    Procedure

    1. If necessary, select Close to exit the MCQA Trend Viewer and MCQA Results Viewer.
    2. Click Quit to exit the MCQA tool.
    3. Close any image files still open on the screen.
    4. Remove all coils and phantoms from the system bore.