Big and little delta for MAP-MRI with ABCD data

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Hello all,

I am trying to fit the MAP-MRI model to processed ABCD data. The dipy implementation of MAP-MRI requires a big delta and little delta value. The big delta, or TR can be easily found, but I can’t seem to find the little delta / pulse length time of the ABCD data set.

Does anyone know where I can find this information?? This would be greatly appreciated!!

Best,
Hank

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Hi Hank,

I don’t know the answer to your original question, but just thought I’d comment that while the DIPY implementation can use this information if provided, it is not required. If you do not provide this information, the DIPY MAP MRI will use a reasonable default.

Cheers,
Ariel

1 Like
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Hello Ariel,

Thank you for the response! What would the effect be of a bad pulse length default (if the real value was abnormally high or low)? I am confused as to why the pulse length is needed for q-space interpretation.

Best,
Hank

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Hello Ariel,

Sorry, I am just following up, I can’t seem to find anything as to how an incorrect pulse length might affect the results. I was wondering your thoughts on the matter.

Best,
Hank