Acetazolamide Stress Brain-Perfusion SPECT Predicts the Need for Carotid Shunting During Carotid Endarterectomy

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FIGURE 1.
One-day protocol of basal and ACZ-SPECT. i.v. = intravenously.
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FIGURE 2.
Severity of reduced rCVR on ^99mTc-ECD ACZ-SPECT. Mild grade indicates reduced rCVR with abnormal distributions that fell into 1 color range from basal SPECT after ACZ administration (10%–20% change). Severe grade indicates reduced rCVR with drop of at least 2 color ranges from basal SPECT after ACZ administration (>20% change).

TABLE 2.

Prediction of Need for Carotid Shunting During Carotid Endarterectomy by Clinical Risk Factors, rCBF, and rCVR on ACZ-SPECT

Predictor of carotid shunting	No. of carotid shunts (%)	Fisher's exact test	Crude odds ratio	Logistic regression
Predictor of carotid shunting	No. of carotid shunts (%)	Fisher's exact test	Crude odds ratio	Odds ratio	P
Age (y)
<59 (n = 21)	2 (9.5)	NS	2.7	4.3	NS
≥60 (n = 54)	12 (22.2)
Sex
Female (n = 12)	1 (8.3)	NS	2.9	0.9	NS
Male (n = 63)	13 (20.6)
Minor stroke or TIA
No (n = 12)	2 (16.7)	NS	1.2	0.4	NS
Yes (n = 63)	12 (19.0)
Diabetes mellitus
No (n = 42)	6 (14.3)	NS	1.9	2.3	NS
Yes (n = 33)	8 (24.2)
Hypertension
No (n = 17)	3 (17.6)	NS	1.1	0.5	NS
Yes (n = 58)	11 (20.0)
Smoking
No (n = 30)	4 (13.3)	NS	1.9	1.7	NS
Yes (n = 45)	10 (22.2)
Contralateral ICA stenosis (%)
<70 (n = 54)	7 (13.0)	P = 0.054	3.4	2.2	NS
≥70 (n = 21)	7 (33.3)
rCBF
Normal (n = 34)	5 (14.7)	NS	1.6	1.5	NS
Reduced* (n = 41)	9 (22.0)
rCVR
Normal (n = 45)	3 (6.7)	P < 0.01	8.1	13.5	<0.01
Reduced† (n = 30)	11 (36.7)
Mild‡ (n = 22)	3 (13.6)
Severe§ (n = 8)	8 (100)

↵* <60% of normal deep ipsilateral cerebellar activity over one third of territory of middle cerebral artery on basal SPECT image.
↵† Abnormal cerebral perfusion that fell into even lower color range from basal SPECT after ACZ administration over at least one third of territory of middle cerebral artery.
↵‡ One color range from basal SPECT after ACZ administration (10%–20% change).
↵§ At least 2 color ranges after ACZ administration (>20% change).
NS = not significant (P > 0.1).

TABLE 3.

Incidence of Carotid Shunting During CEA According to Types of ^99mTc-ECD ACZ-SPECT Findings and Severity of Contralateral ICA Stenosis