Comparison of conventional region of interest and statistical mapping method in brain single-photon emission computed tomography for prediction of hyperperfusion after carotid endarterectomy.
OBJECTIVE
Hyperperfusion after carotid endarterectomy (CEA) has been proposed as the main mechanism of intracerebral hemorrhage, which is a disastrous complication. The aim of this study was to compare the predictive value of cerebral blood flow (CBF) abnormalities for hyperperfusion after CEA with the conventional region of interest (ROI) analysis and statistical brain mapping analysis.


METHODS
For 46 patients with unilateral carotid stenosis of 70% or more, CBF and cerebral vasoreactivity were investigated with resting and acetazolamide-challenge single-photon emission computed tomography before CEA and 1 day after CEA. Three-dimensional stereotactic surface projection (3-D-SSP) analysis of CBF changes was performed by automatic quantification with a predefined template.


RESULTS
Logistic regression analysis demonstrated CBF reduction (z-score) to be the only significant variable for postoperative hyperperfusion on 3-D-SSP with thalamic normalization but no significant variable with the ROI method. Receiver operating characteristic (ROC) analysis demonstrated significant improvement in the predictive value of CBF reduction (z-score) on 3-D-SSP (area under the ROC curve = 0.93) in comparison with the ROI method (area under the ROC curve = 0.78) (P = 0.049). According to the optimal cutoff values provided by ROC analysis, patients were categorized into two groups: Type I (CBF decrease < 20%, n = 23) and Type II (CBF decrease > or = 20%, n = 23) on ROI analysis and Type A (z-score < or = 2, n = 40) and Type B (z-score > 2, n = 6) on 3-D-SSP. There was a significant difference in incidence of hyperperfusion between Type A (1 of 40) and Type B (5 of 6) on 3-D-SSP (P = 0.00003) but not between Type I (1 of 23) and Type II (5 of 23) on ROI analysis. Cerebral vasoreactivity did not show significant value in the prediction of hyperperfusion with either the ROI or the 3-D-SSP method.


CONCLUSIONS
Objective assessment of CBF status, especially baseline CBF reduction (z-score), with automatic quantification by 3-D-SSP with normalization had a higher diagnostic value than conventional ROI analysis to identify patients at risk for hyperperfusion after CEA.
Department of Neurosurgery, Hyogo Emergency Medical Center, Kobe Red Cross Hospital, Kobe, Japan. khosoda@venus.dti.ne.jp
Kohkichi
K
Hosoda
Tetsuro
T
Kawaguchi
Kazunari
K
Ishii
Satoshi
S
Minoshima
Eiji
E
Kohmura
D000086:Acetazolamide; D000368:Aged; D000369:Aged, 80 and over; D000927:Anticonvulsants; D001931:Brain Mapping; D016893:Carotid Stenosis / Q000473:pathology* / Q000628:therapy; D002543:Cerebral Hemorrhage / Q000209:etiology* / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D016894:Endarterectomy, Carotid / Q000009:adverse effects*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D015899:Tomography, Emission-Computed, Single-Photon
D000927:Anticonvulsants; D000086:Acetazolamide