MRI Studio Forum » Diffeo Map

Normalization of a ADC map

(6 posts)
  • Started 7 years ago by yongzhangdti
  • Latest reply from joetraff
  1. yongzhangdti
    Member

    Hello,

    Many thanks for the great help from this forum! I've successfully performed an affine transform for a DTI dataset. As suggested by the user manual, I normalized a tensor file and then re-calculated the FA map. Now I have linearly co-registed FA, eigenvectors, eigenvalues and colormaps. But what should I do with a ADC map? It seems there is no re-created ADC map from the AIR affine transform. Should I normalize the ADC map directly or I can built it on any other co-registered image? Any hint will be greatly appreciated!

    Yong

    Posted 7 years ago #
  2. susumu
    Member

    Hi Yong,

    I assume that you normalized the tensor and reloaded it to DtiStudio to recalculate all the maps. One of them should be "trace". If you divide this number by 3, you get what people call "MD: mean diffusivity" or "ADC: average diffusion constant".

    Let me know if you can't find "trace" after tensor recalculation.

    Posted 7 years ago #
  3. yongzhangdti
    Member

    Hi Susumu,

    After tensor recalculation, all we have are the tensors in six directions (Dxx, Dyy, Dzz, Dxy, Dxz and Dyz), eigen values, eigen vectors, FA, RA, VR and colopmaps. We may have to calculate the average of Dxx, Dyy and Dzz manually. Trace can be acquired only during the inital calculation with DTI Studio using the raw DWI data. Please correct me if there was something wrong or missing. Many thanks!

    Yong

    Posted 7 years ago #
  4. JHMI_Hangyi
    Member

    on the top-right of the tensor calculation dialog, checking the "TRACE" option, you will get the TRACE=Dxx+Dyy+Dzz

    Posted 7 years ago #
  5. yongzhangdti
    Member

    Thank you very much, Hangyi! I feel trace can be calculated only from the tensor calculation dialog as you've mentioned. As for tensor recalculation after affine or non-linear transform, we may have to re-calculate trace manually.

    Posted 7 years ago #
  6. joetraff
    Member

    Your help is much obliged hangyi.
    Keep up the good work.

    Posted 7 years ago #

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