Any Attributes that refer to start and end times such as Acquisition Time (0008,0032) and Content Time (0008,0033) must be updated to reflect the new start time if the first frame is not the same as the original. This is typically the case where the multi-frame object is a "video" and where the first frame is not included. Likewise, Image Trigger Delay (0018,1067) may need to be updated.