• Object ID: 00000018WIA30C3DD20GYZ
  • Topic ID: id_13106622 Version: 5.0
  • Date: Feb 3, 2021 2:44:17 AM

Multi-Coil Quality Assurance (MCQA) Tool

Prerequisites

Table 1. Personnel requirements
Required personsPreliminary requirementsProcedureFinalization
1Depends on coilDepends on coilNot Applicable
Table 2. Tools and test equipment
ItemQuantityEffectivityPart numberManufacturer
Coils and phantoms for all coils to be testedN/A---
Table 3. Required conditions
ConditionReferenceEffectivity

Set up coil and phantom

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About this task

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

The tool does not rely on region of interest (ROI) placement as other SNR tools have 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.

Run MCQA Tool

About this task

Procedure

  1. From the Common Service Desktop, click Service Browser, and select the Image Quality tab. Click the Multi-Coil QA Tool link, then select Click here to start this tool. The MCQA tool displays.
    Figure 1. MCQA Tool
  2. During startup, the MCQA tool attempts to identify the coil connected to the system. The Current Coil field automatically populates the coil name based on the coil ID of the coil connected to the LPCA.

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

    • The names listed are the physical coil names and specific to the coil connector.

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

    • If the tool detects an incorrect coil selection during the download, an error message displays. Manually select the correct coil from the Current Coil drop-down field.

    Note:

    The Help menu displays assistance with the MCQA setup procedure for GEM coils only.

  3. Enter the coil serial number in the Coil Serial # field.
  4. Position the coil and phantoms according to the QA test in the coil vendor manual.
  5. In the MCQA tool window, select Start to begin the test.
  6. When a confirmation popup displays asking you to continue with the selected phantom set, click Yes.

    We recommend that you perform Coil Datapath Diagnostic, which uses MRCv Tool, prior to performing MCQA and make sure it passes. However, the Coil Datapath Diagnostic is not a prerequisite for MCQA.

  7. A warning dialog displays asking you to verify the coil/phantom setup and position. Ensure that the phantom and coil setup is correct, and select Yes to continue.

    The status window of the MCQA tool continuously updates to provide information on what the tool is doing at that time.

    A time bar also displays, showing approximate total test time, elapsed time, and percent complete.

  8. After the test is completed, the test results file name displays in the Results File field and the Pass/Fail field shows the overall test result.

    The MCQA tool may have a FAIL test result for reasons including, but not limited to:

    • Bad coil element(s)

    • Incorrect phantom used for testing

    • Incorrect positioning/placement of phantom

  9. Select QUIT to exit the MCQA tool. Remove the coil and phantom from the system.

View Report Results

Procedure

  1. After running the MCQA test, select View Report Details to review the results. The MCQA Viewer displays.

    The Results File and Pass/Fail Status are listed across the top of the viewer.

    The test results display in the Results window on the left side of the viewer.

    To review past results: select File > Open Results File, and select the desired coil results file.

    Figure 2. MCQA Viewer
    Figure 3. MCQA Viewer Showing %SNR Variance
  2. Use the MCQA Viewer options to retrieve the exact report you want to see:
    2. To review the results of the same coil, but for a different test, select the appropriate number from the Test # scroll box near the bottom of the screen.
    3. To graph the data, select one of three choices: Isig, Noise or Isnr. The corresponding results display in the window to the right. The integrated signal, noise, or integrated SNR values are listed on the vertical axis with the images along the horizontal axis.
    4. To graph the Isnr specification values in addition to the data, select the Isnr Specs box below Test # near the bottom of the viewer.
    5. The graph results automatically scale according to the data values. To manually change the vertical scale, enter the value into the Ymax and/or Ymin fields at the top right of the viewer.
    6. To view all the signal or noise images, select View Signal Imgs or View Noise Imgs, and an image viewer displays with one image per coil element, ordered left-to-right and top-to-bottom as shown in the example below.
      Figure 4. Example of Signal and Noise Images
  3. From the MCQA Viewer, select Plot noise CC to display a 3D plot of the noise cross-correlation data for the results being viewed. The data shows the relative cross correlation of noise between receiver channels. See the illustration below for an example plot.

    • Green data shows a one-to-one correlation.

    • Red data shows correlations above the threshold.

    Figure 5. Example 3D Plot of Signal and Noise Images
    Note:

    There are currently no specs for the noise cross-correlation data. It may be possible to determine patterns per coils and set specs as more data is collected.

MCQA Trend Viewer

About this task

Every time a MCQA test is completed, a new results file is generated. Past MCQA results are stored on the system, which allows for trending of ISNR data over time. These results can be graphically trended using the MCQA Trend Viewer. All the files available for trending are listed in the Results Files window at the left.

Procedure

  1. On the MCQA Viewer, select Trend Data.

    The MCQA Trend Viewer displays.

    Figure 6. MCQA Trend Viewer
  2. Select the Test # and Image # for the data you want to review.
  3. Choose Isig, Noise, or Isnr to display the type of graph you want to see.
  4. The data displays over time (number of tests run). To change the vertical scale, enter new values into the Ymax and/or Ymin fields at the top of the screen.

    Statistics about the existing data are shown in the lower left of the viewer.

Finalization

Procedure

  1. Click Quit to exit the MCQA tool.
  2. Close any image files still open on the screen.
  3. Remove all coils and phantoms from the system.