dicom tag frame of reference UID of sequential spatial-related image sets

Question

normally you can only put sequential image sets (for instance of two parts of the lower leg) in spatial relationship to each other when they have an identical frame of reference UID (dicom tag 0020,0052). But are there exceptions for differences of frame of reference UID of two different image sets for still being spatial intercomparable? for instance, can there be differences just because of; - different plane of images (axial versus sagittal images)? - distortion correction yes or no? - type of distortion correction on type of images (e.a.2D distortion correction on 2D images or 2D distortion correction on 3D images)?

Do the separate numbers in the frame of reference UID number have any meaning?

Answer 1

You've asked several questions here. I'll answer one of them. "Do the separate numbers in the frame of reference UID number have any meaning?"

No. While it's often the case that recognizable data such as date and time are incorporated as a portion of a UID, the details of how UIDs are generated are entirely at the discretion of the implementer and are subject to change at a whim. The numbers in a UID should never be interpreted as having a meaning. The DICOM standard simply requires that UIDs be globally unique, fit the specified maximum length constraint, and follow the specified format of numbers and dots.