TABLE 4:

PCT rCBV values for the ischemic area

GroupSampling Interval
0.5 second1 second*2 seconds3 seconds4 seconds5 seconds6 seconds
1 (30 mL)
 Mean ± SD1.0 ± 0.41.2 ± 0.51.1 ± 0.52.2 ± 0.43.7 ± 0.65.4 ± 1.512.1 ± 4.8
 Range−14.4% to +8.6%NA−10.2% to +8.5%+33.7% to +111.2%+104.2% to +335.0%+222.0% to +447.4%+630.5% to +1275.2%
P value.018NA.519<.001<.001<.001<.001
2 (40 mL)
 Mean ± SD1.1 ± 0.31.2 ± 0.41.1 ± 0.41.2 ± 0.43.2 ± 0.55.1 ± 0.910.9 ± 2.8
 Range−13.0% to +13.7%NA−10.5% to +8.1%−10.6% to +10.2%+53.0% to +220.5%+197.3% to +427.3%+510.8% to +937.3%
P value.156NA.076.765<.001<.001<.001
3 (50 mL)
 Mean ± SD0.9 ± 0.51.1 ± 0.31.0 ± 0.31.1 ± 0.62.3 ± 0.33.4 ± 0.54.3 ± 0.9
 Range−12.4% to +10.6%NA−8.1% to +8.5%−10.5% to +9.4%+33.5% to +122.3%+95.5% to +323.7%+249.7% to +435.4%
P value.021NA.033.603<.001<.001<.001
4 (60 mL)
 Mean ± SD1.0 ± 0.41.0 ± 0.50.9 ± 0.60.9 ± 0.41.1 ± 0.32.0 ± 0.32.4 ± 0.4
 Range−11.3% to +10.4%NA−7.2% to +7.2%−9.5% to +9.3%−11.8% to +12.1%+23.3% to +155.9%+97.9% to +228.1%
P value.614NA.164.172.014<.001<.001
  • Note.—No significant difference (P = .556, Kruskal-Wallis) was identified among the four groups for rCBV values obtained with an interval of 1 second. Range indicates the overestimation or underestimation compared with the reference. Values in boldface indicate the temporal sampling interval thresholds beyond which rCBV values were significantly overestimated.

  • * Reference for Wilcoxon (Mann-Whitney) tests performed in each group. NA indicates not applicable.