- We will search our imaging database from 2009 to current. Included will be all gun site MRI studies obtained at PCMC or the UOC for evaluation of rotational profile. We will exclude any study in which images are not sufficient to obtain all of the required measurements needed for our study. A preliminary review of the imaging database has identified 42 potential studies. Our power analysis calls for 15 patients to be included to obtain a 95% confidence interval.