Hi Hai,
I agree with Bruce. In a recent paper (http://www.ncbi.nlm.nih.gov/pubmed/23668971), for a variety of 3T vendor and coil configurations, we confirmed previous findings that averaging two within-session uncorrupted MPRAGE scans did not significantly improve across session reproducibility. In you case just choose the best one of the two.
Is it worth acquiring two MPRAGES then? Tricky. Maybe you can go for only a single acquistion if your MR operator is experienced to distinguish what level of artifact will be unacceptable for the target analysis and deserves a repeated acquisition in case of unacceptable quality. Otherwise, one may fix two acquisitions in the protocol and use the best of them. Nevertheless, the operators should always be paying attention to the data quality during the acquisition to decide if some type of intervention can help.
cheers,
jorge
On 06/01/2014 21:38, Bruce Fischl wrote:
Hi Hai_______________________________________________
it really depends on your coil and field strength, and whether either is
motion-corrupted. For 3T 32 channel data our somewhat ad hoc opinion is
that one is better than two (due to blurring induced by interpolation),
but it's really a case-by-case decision.
sorry that there isn't an easier answer
Bruce
On Mon, 6 Jan 2014, Hai Pan wrote:
Hello, FreeSurfer experts,
We made two T1 scans for each subject at each session, will they be helpful
for better recon-all results? Shall I average them and process the averaged
T1 image? Let me know please.
Thank you,
Hai
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