I am trying to compute the distance (could be euclidean or geodesic) between two MNI coordinates in MNI space/ I tried using the connectome workbench but to no avail.

Is there an efficient and reliable way to do this. eg, the distance between Point 1 (-60 , -7, 38) and point 2 (-61 -6, 41)

X and y and z are distances in mm, which you would get by the difference in x,y,z coordinates between the points (multiplied by the size of the voxel).