@JuliaM -
If you have an image that shows your skull & cervical spine from the back, that would give you the best view of your C-1 vertebra. If it’s sitting at an angle as opposed to lying more perfectly horizontal, that can be an indicator that it is off kilter. Bear in mind that the position of your head during the scan can give a false impression of the C-spine being misaligned. If you know you were lying perfectly aligned during your scan (i.e. your head was in neutral position as opposed to looking slightly left or right) & you see C-1 tilted in the image, there’s a greater chance it has a problem.
Here’s a link to a thread w/ a video about one of our members, @jteleia, who has big problems from her C-1 which were helped somewhat by an atlas orthogonal specialist. Still no resolution - #3 by KoolDude