Sissy Spacek was originally cast as Dr. Weaver's mother, but was eventually played by Frances Fisher in episode "Just as I Am" (2005).
Dr. Mark Greene:
Doug, you have a problem?
Dr. Doug Ross: No, just call me Mr. Blue.
In episode 14.7, BLACKOUT, the show starts with Abbey and her son at the airport with a cut on the left side of her forehead, then the show goes back in time 15 hours. When we see how she gets the cut, she bumps her head on the door frame of the back door of a cab, but she hits it with the right side of her forehead, and when the show catches up with the beginning, the cut is back on the left side of her forehead.
All episodes before "The Visit" (airdate: 16 November 2000) were shot and broadcast in the standard television aspect ratio of 1.33:1. All subsequent episodes are done in the HDTV ratio of 1.78:1. However, the DVD collection has reformatted versions of all the early season episodes in 1.78:1. They went back to the original negatives and "matted" off the top and bottom parts of the screen, but gained visuals on the left ands right sides that were never seen before .