Time Course of Cerebrovascular Reactivity in Patients Treated for Unruptured Intracranial Aneurysms: A One-Year Transcranial Doppler and Acetazolamide Follow-Up Study

Table 3

Blood flow velocities and cerebrovascular reactivity at baseline and follow-up.

	First exam	Follow-up	Absolute difference	Relative difference
	mean (SD)	mean (SD)
(cm/s)
Ipsilateral	59.8 (13.8)	51.2 (13.3)	−8.6	0.86	<0.001
Contralateral	57.7 (14.7)	52.0 (12.1)	−5.7	0.90	0.003
Mean	58.6 (13.2)	51.4 (11.7)	−7.2	0.88	<0.001
(cm/s)
Ipsilateral	93.6 (18.0)	84.4 (20.2)	−9.2	0.90	0.001
Contralateral	93.4 (23.3)	85.0 (20.1)	−8.4	0.91	0.009
Mean	94.3 (20.0)	84.4 (18.5)	−9.9	0.90	<0.001
ΔMFV (cm/s)
Ipsilateral	33.8 (9.2)	33.1 (9.8)	−0.7	0.98	0.43
Contralateral	35.7 (11.2)	33.0 (11.8)	−2.7	0.93	0.15
Mean	35.7 (10.2)	33.1 (9.9)	−2.7	0.93	0.09
CVR (%)
Ipsilateral	58.9 (19.3)	66.1 (18.5)	7.2	1.12	0.04
Contralateral	63.4 (17.5)	65.0 (23.6)	1.7	1.03	0.65
Mean	62.7 (17.2)	65.6 (19.4)	2.9	1.05	0.31
MV ()
Ipsilateral	7	3
Contralateral	1	1

CVR: cerebrovascular reactivity; : baseline mean blood flow velocity (before acetazolamide); : maximum mean blood flow velocity after acetazolamide; ΔMFV: absolute change in mean flow velocity after acetazolamide; MV: missing value; : value from paired -test (follow-up–first); SD: standard deviation. Note that if one side had a missing value, the mean is just the remaining value. This is why the mean is not simply the mean of ipsilateral and contralateral values. Patients with MV were excluded from the paired -test. The sample size was therefore reduced in the analyses of ipsilateral and contralateral values (ipsilateral , contralateral , mean ).