ADNI3 ASL question -- Siemens 3D PASL CBF values

[Patrick Pruitt]

Hi ADNI experts:

I'm hoping to learn a bit more about the processing of the ADNI3 ASL data that produced the CBF values in Imaging -> MR Image Analysis -> "UCSF - ASL Perfusion CBF by FreeSurfer ROI [ADNI3] (Version: 22-08-17)". While most CBF values are in the expected range, the values for Siemens 3D PASL are on the order of hundreds or thousands.

My understanding is that the Siemens 3D PASL sequence used background suppression and did not collect a separate M0 image -- and were therefore, I assume, not able to undergo the same quantification that the other ASL sequences were. With that in mind, I guess I'd be interested to know a bit more about the approach that produced the 3D PASL CBF values that are in the document, and whether they have any practical meaning in the way the CBF values from the other sequences do.

(I took a look at the ASL Perfusion Processing Methods PDF from the Study Data, but it appears to be out of date with regards to ADNI3 [2012-12-04]).

Many thanks in advance to any insight that you might provide!

-Patrick

[Danielle Sanchez]

I'm having similar concerns myself - are there any updates on this thread?

Many thanks,

-Danielle

[Danielle J Harvey]

Hi all,

 

I received the following information from the group that processes the ASL information:

 

Siemens 3D PASL sequence does not include an M0 image for us to estimate quantitative CBF. Average control images were used as a surrogate M0 image. That's why the CBF scale is different from GE 3D PCASL values. The Siemens PASL results should be treated as relative CBF values.

 

Danielle

--
You received this message because you are subscribed to the Google Groups "Alzheimer's Disease Neuroimaging Initiative (ADNI) Data" group.
To unsubscribe from this group and stop receiving emails from it, send an email to adni-data+...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/adni-data/f6326a04-5949-4f66-a9f8-9ef718c5a7can%40googlegroups.com.

**CONFIDENTIALITY NOTICE** This e-mail communication and any attachments are for the sole use of the intended recipient and may contain information that is confidential and privileged under state and federal privacy laws. If you received this e-mail in error, be aware that any unauthorized use, disclosure, copying, or distribution is strictly prohibited. If you received this e-mail in error, please contact the sender immediately and destroy/delete all copies of this message.