Brain VOI Editing and Statistics Calculation

The result of structure outlining is shown on the VOIS page.

The image display shows a fusion of the MR image with the averaged PET image in the selected Result space. Please use the fusion slider to change the weight between the image contributions, and use the individual image control tabs for the changing the individual image displays. The example below shows the contour VOIs with 50% mixing and MR only.

VOI Editing and Selection

At this time the contour VOIs can be interactively adjusted using the VOI features of PMOD, which are described in the PMOD Base Functionality Guide. Note that the List tab should be selected for the adjustment, and that depending on the configuration only a reduced set of VOI tools may be available.

A subset of the VOIs can easily be selected on the Group tab as described above.

Statistics Calculation

Once the VOIs are acceptable, it is recommended to first save them and then proceed with statistics calculation by the Statistics action button. The result (of the selected VOIs only) is shown on the separate Statistics page of the PNEURO tool, from where it can be further evaluated.

Partial-Volume Correction (PVC) Option

The PNEURO tool supports the GTM-based patial-volume correction (PVC) of the PET signal.

The PVC selection has three choices:

• NONE: No partial-volume correction is applied (default).
• LMA GTM: A variant of the Rousset correction method is applied, whereby only a percentage of the pixels in the inner of the VOI is used for calculating the VOI average. This percentage can be set by the Voxels to be kept parameter.
• VOI BASED: The original Rousset correction method is applied.

If a PVC method is used, both the original and the corrected statistics are calculated. Note that due to the high number of VOIs the PVC calculation may take several minutes and consumes a significant amount of RAM.