Effect of Stenting on Cerebral CT Perfusion in Symptomatic and Asymptomatic Patients with Carotid Artery Stenosis

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Fig 1.
Manual outlining of middle cerebral artery territory on transverse CT sections, according to the maps of Damasio.²⁰
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Fig 2.
Relative CTP values measured before and after treatment in symptomatic and asymptomatic patients: rCBV (A), dMTT (B), and rCBF (C).
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Fig 3.
A, Example of symptomatic patient with a left-sided carotid artery stenosis of 99%. Before treatment, CBF and MTT show explicit differences between the right and left hemispheres with a higher CBF and a higher MTT in the right hemisphere in comparison with the left hemisphere. After CAS, both CBF and MTT show a symmetric pattern of perfusion. B, An example of a asymptomatic patient with a left-sided carotid artery stenosis of 95%. Before treatment, CBF and MTT show differences between the right and left hemisphere with a higher CBF and a higher MTT in the right hemisphere in comparison with the left hemisphere. However, this difference is not as clear as in the symptomatic patient. After CAS, both CBF and MTT show a symmetric pattern of perfusion.

Table 1:

Patient characteristics (n = 45)

Patient Demographics	Symptomatic Patients (n = 31)	Asymptomatic Patients (n= 14)	P Value^a
Age (yr) (mean) (range)	67.0 ± 10.4 (43–82)	69.6 ± 9.0 (56–82)	.43^b
Male (No.) (%)	21 (67.7)	13 (92.9)	.13^c
Carotid arteries
Left side treated (No.) (%)	15 (48.4)	9 (64.3)	.32
Stenosis grade (%), mean ± SD (range)	89.5 ± 9.4 (65–99)	88.9 ± 5.8 (75–99)	.32^b
Symptoms
Stroke (No.) (%)	11 (35.5)	None	N.A.
TIA (No.) (%)	13 (41.9)	None	N.A.
AF (No.) (%)	7 (22.6)	None	N.A.
Interval in days
Pretreatment CTP to treatment (mean) (range)	3.2 ± 6.4 (0–35)	3.5 ± 1.9 (3–10)	.03^b
Treatment to posttreatment CTP (mean) (range)	33.9 ± 4.8 (22–44)	71.9 ± 82.6 (8–263)	.84^b
Medical history
Hypertension (No.) (%)	25 (80.6)	13 (92.9)	.41^c
Diabetes mellitus (No.) (%)	3 (9.7)	3 (21.4)	.36^c
Hypercholesterolemia (No.) (%)	12 (38.7)	12 (85.7)	.008
Smoking (No.) (%)	10 (32.3)	6 (42.9)	.52^c
Previous myocardial infarction (No.) (%)	4 (12.9)	3 (21.4)	.66^c
Previous CABG (No.) (%)	2 (6.5)	1 (7.1)	1.00^c

Table 2:

Comparison of pre- and posttreatment CTP data for symptomatic and asymptomatic patients^a

Pre- and Posttreatment	rCBV (mL/100 g) (mean)	P Value	dMTT (s) (mean)	P Value	rCBF (mL/100 g/min) (mean)	P Value
Symptomatic patients before treatment (n = 31)	1.02 ± 0.13		1.29 ± 1.21		0.81 ± 0.14
Symptomatic patients after treatment (n = 31)	0.95 ± 0.14	.036^b	0.14 ± 1.08	<.001^b	0.93 ± 0.17	<.001^b
Asymptomatic patients before treatment (n = 14)	1.03 ± 0.08		0.56 ± 0.66		0.92 ± 0.12
Asymptomatic patients, after treatment (n = 14)	1.05 ± 0.13	.221	0.06 ± 0.55	0.081	1.03 ± 0.14	.026^b

↵a The significance of the difference between relative perfusion parameters was tested using the paired-samples t test in symptomatic patients and the Wilcoxon signed rank test in asymptomatic patients.
↵b Significant difference with a P value < .05.

Table 3:

Comparison between symptomatic and asymptomatic patients in pre- and posttreatment values^a

Pre- and Posttreatment	rCBV (mL/100 g) (mean)	P Value	dMTT (s) (mean)	P Value	rCBF (mL/100 g/min) (mean)	P Value
Symptomatic patients before treatment (n = 31)	1.02 ± 0.13		1.29 ± 1.21		0.81 ± 0.14
Asymptomatic patients before treatment (n = 14)	1.03 ± 0.08	.902	0.56 ± 0.66	.061	0.92 ± 0.12	.009^b
Symptomatic patients after treatment (n = 31)	0.95 ± 0.14		0.14 ± 1.08		0.93 ± 0.17
Asymptomatic patients after treatment (n = 14)	1.05 ± 0.13	.009^b	0.06 ± 0.55	.573	1.03 ± 0.14	.056

↵a The significance of the difference between relative perfusion parameters was tested using the Mann-Whitney U test.
↵b Significant difference with a P value < .05.