Figure 3b: (a, b) Graphs show correlation between blood flow changes at CT perfusion and laser Doppler flowmetry. Results for both observers are shown for single- and multisection techniques. When the accuracy of single- and multisection CT techniques used to calculate decreases in blood flow was compared with that of laser Doppler flowmetry, good correlations were achieved for both techniques. Lines represent the relationship between the reference standard and the single- or multisection technique for each observer.