ObsA-Dataset1 (1st analysis) vs. ObsA-Dataset1 (2nd analysis) to determine of repeatability ObsA-Dataset1 vs. ObsA-Dataset2 to determine variability caused by repeating the procedure ObsA-Dataset2 vs. ObsB-Dataset2 to determine inter-observer variability by reading ObsA-Dataset1 vs. ObsB-Dataset2 to determine inter-observer variability caused by repeating the exam