Was the same ultrasound machine used for both exams? Were both exams performed by the same technologist? Were the Doppler angles the same in both cases? Was the patents blood pressure similar in both cases?
I ask these questions because there are concerns about different velocity measurements on the same patient with different equipment. Also there can be technique variability between technologists in the way the exam is done. Comparing ICA/CCA velocity ratios might enable us to better appreciate a big difference in exam results.