I am presently trying to calculate hippocampal volume for two different study groups. One study group images (MDD) was acquired on 1.5T and the other age-matched study group (Healthy controls) on 3T MRI. On doing the statistics I have significant differences in the hippocampal volume correlating with their cognitive scores between the two study groups. Do I need to take into consideration different scanner parameters when doing the statistics? How do I go about it?