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Vue PACS MR Perfusion User Guide Unrestricted Internal Use
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Vue PACS MR Perfusion User Guide - AE9362.docx
Maps
Based on the various diffusivity measures, the system generates a diffusion tensor and calculates the
tensor’s eigenvalues
λ
1,
λ
2,
λ
3 (
λ
1 >
λ
2 >
λ
3) and eigenvectors V1, V2, V3 respectively.
The following maps are shown:
Maps reflecting isotropic diffusivity
1
•
ADC—Simulates the isotropic scan and is equal to the average of the eigenvalues
(
λ1
+
λ
2+
λ
3)/3.
•
eADC—Calculated by exp(-b*ADC) for a prefixed b value.
•
DWI—Isotropic map that multiplies the eADC by the T2 image (b=0) or by a T2 extrapolation
(in cases when there is no b=0 image or when there are several such images).
Maps reflecting anisotropic diffusivity
1
•
Ax diff—The largest eigenvalue (
λ
1)
•
Rad diff—The average of the two smaller eigenvalues (
λ
2+
λ
3))/2
•
FA—Measures the difference between the isotropic diffusion measurement and the
directional measurement.
•
RA—Measures the ratio of the isotropic diffusion measurement to the directional
measurement.
•
FA dir—A color map, showing the color coding of the main direction of diffusivity (V1) relative
to the main axes X, Y, Z. Red indicates the main direction X, green indicates the main
direction Y, and blue indicates the main direction Z. At each point, the displayed color may be
either a mixture of red, green, and blue, based on the diffusion component, or only red, only
green, or only blue, based on the component of the maximal value. The system may be
configured to display the colors by one of these coloring options. See your system
administrator to change the coloring option.
Table
•
If you add an ROI, a table presenting the calculated values in the ROI is displayed on screen.
6.3 Using the Brain Mask Correction Tool
You can display and hide the brain mask in the displayed input images.
6.3.1 Displaying the Brain Mask
To display the brain mask, click the brain mask icon in the Correction Tools section of the
Perfusion ribbon. The brain mask is displayed both on the TMIP and the dynamic images.
6.3.2 Adding Brain Mask
To manually add brain mask on the displayed image –
1. Click Add Brain Mask in the drop-down menu of the Show/Hide Brain Mask icon.
2. Click the left mouse button at the point where you wish to start adding brain mask to the
image.
3. Drag the mouse to add brain mask.
4. Left-click the mouse again to end the brain mask addition.