• Object ID: 00000018WIA305AB890GYZ
  • Topic ID: id_2036693 Version: 1.1
  • Date: Jun 30, 2022 3:39:21 AM

PROSE spectrum visualization procedure

About this task

Use these steps to visualize and examine a PROSE spectrum after a PROSE prescription is saved and the Spectro Prescan button displays.

Step-by-step instructions

  1. Click Spectro Prescan to open the Spectroscopy Prescan screen.
  2. Verify that the Entry Point text box value is single1
  3. Click Start to acquire a spectrum from the entire PROSE volume. No phase encoding gradients are played out during this acquisition.
  4. Click on the display waveform menu (bottom left edge of the display window) and choose Magnitude for the top display and Pure Absorp for the bottom display.
    • If you have selected an “endo-rectal coil only” coil configuration, e.g., 8EIS_eCoil, signals from the endo\u0002rectal coil are displayed.
    • If you are using a full phased array coil set, e.g., 8EIS_eCoil BodyL, you may have to select the endo-rectal coil to see the correct signal.
  5. Click Apply
    • The spectra in the display windows should have the water peak near the center of the window. It may be possible to see the metabolite peaks to the right of the water peak.
    • You may have to increase the display scale (the up/down arrows below the display windows) in order to observe the metabolite peaks.
    • The pure absorption display is the better spectral display, but usually requires a Zero Order Phase adjustment.
    • Use the Zero Order Phase slider to make the peak in the pure absorption display window look like the magnitude display.
    • It should never be necessary to change the First Order Phase.
    • The baseline should be level on both sides of the water peak.
    • The magnitude display is always positive, but the peaks are broader than the pure absorption peaks and may be distorted.
  6. If you see a large lipid resonance that obscures the prostate metabolite resonance peaks, check and correct the placement of the VSS bands to eliminate the unwanted lipid signals.
  7. Broad metabolite peaks are indicative of poor homogeneity. If the peaks are too broad, make the recommended checks and adjustments.
    • Check the position of the PROSE volume relative to the rectum and endo-rectal coil. Reposition the volume as necessary.
    • Check the locations of the prescribed VSS bands. The VSS bands can be used to suppress signals from regions of high inhomogeneity, i.e., the endo-rectal coil and the rectum.
    • Manually adjust the X, Y, and Z gradient currents to improve the homogeneity with Gradient Shimming.
  8. Click Done to exit the Spectroscopy Prescan screen.