Hi FreeSurfer Community,

 

I plan to use longitudinal FreeSurfer to process a set of longitudinal scans that are likely to create a bias in the base template. Specifically, our study consists of 3 scans acquired within the first 20 weeks and a subsequent scan acquired 2 years after the third scan.

 

From the original publication on longitudinal FreeSurfer, I understand that the longitudinal scans are treated equally and do not require to be evenly distributed in time, and that the cross and base images are only used to initialize the longitudinal processing. However, my concern is that the resulting template, based on the median, will be too similar to the first three scans.

 

Would this negatively impact the results of the 4th scan, due to the inherent bias of the template? Has any group investigated this before?

 

Any feedback would be appreciated!

 

Best regards,

Maksim