Figure 2.

A representation of the thrombus characteristics that are calculated from the histogram of Hounsfield Unit (HU) intensity values of the thrombus in NCCT (green) and CTA (red). Three TAI (Thrombus Attenuation Increase) values are calculated from the difference between the first, second, and third quartiles (Q1, Q2, and Q3) of the two histograms. TAI_MCC (maximum cross correlation) is a measure of how much the NCCT histogram should be moved to achieve the maximum cross correlation with the CTA histogram. The distribution showed with a green, dashed line is the shifted NCCT histogram. Heterogeneity is defined as the CTA and NCCT SD (Standard Deviation). Density is shown as the CTA and NCCT median. In this figure, we have assumed the two histograms are normal distributions. In case of a non-normal distribution, median values do not overlap with the second quartile, and TAI_MCC is not necessarily the exact distance between the two medians.