sure!
1st you should know if spar are measured as 2 port or 1 port.
2nd put the spar file into a simulator, if 2 port, short to gnd the out port.
3rd plot Real and Immaginary part of input reactance vs Freq.
4th compute Q= |jX|/R
5th note that for spar measured near external Smith Circle, the accuracy of the calculated Q is poor or bad.