# SNR and Number of Signal Averages

As usual, get out the SNR equation. Change NEX to 2NEX. What is the result on the SNR?

We'll get a √2 increase in SNR if NEX is doubled.

Tradeoff: Longer scan time, disproportionate to increase in SNR.

Further reading on this topic:

Books: Q&A in MRI p99, MRI The Basics p168

Online: MRItutor 1, 2