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Table 2 Comparison of absolute ipsilateral PET values and hemispheric ratios with TCD CO 2 -reactivity

From: Comparison of oxygen-15 PET and transcranial Doppler CO2-reactivity measurements in identifying haemodynamic compromise in patients with symptomatic occlusion of the internal carotid artery

  All patients Impaired CVR (≤20%) Normal CVR (>20%) p value Absent CVR or steal (≤0%) No absent CVR or steal (>0%) p value Test
n = 24 n = 17 n = 7 n = 6 n = 18
CO2-reactivity (%), mean ± SD 15.5 ± 15.9 7.0 ± 8.7 36.0 ± 9.0   −2.7 ± 4.8 21.6 ± 13.5   
CBF (mL/min/100 mL), mean ± SD 31.9 ± 5.6 32.3 ± 6.0 30.9 ± 4.8 0.572 30.8 ± 5.0 32.3 ± 5.9 0.598 t
CBF ratio, mean ± SD 0.88 ± 0.09 0.87 ± 0.08 0.90 ± 0.12 0.461 0.84 ± 0.09 0.89 ± 0.09 0.178 t
OEF (%), median (IQR) 45.1 (42.2 to 50.9) 45.0 (42.5 to 50.1) 47.8 (40.2 to 55.2) 0.634 47.6 (42.1 to 58.4) 45.0 (41.5 to 50.8) 0.424 U
OEF ratio, median (IQR) 1.06 (1.00 to 1.11) 1.06 (1.01 to 1.11) 1.08 (0.97 to 1.12) 0.949 1.09 (1.04 to 1.26) 1.05 (0.99 to 1.10) 0.116 U
CBV/CBF, mean ± SD 0.10 ± 0.03 0.10 ± 0.03 0.11 ± 0.03 0.563 0.09 ± 0.04 0.10 ± 0.02 0.266 t
CBV/CBF ratio, mean ± SD 1.27 ± 0.18 1.32 ± 0.15 1.15 ± 0.21 0.035 1.36 ± 0.15 1.24 ± 0.18 0.174 t
  1. CBF, cerebral blood flow; CBV, cerebral blood volume; CVR, cerebrovascular reactivity; IQR, interquartile range; OEF, oxygen extraction fraction; t, Student’s t test; U, Mann–Whitney test.