Preoperative Central Benzodiazepine Receptor Binding Potential and Cerebral Blood Flow Images on SPECT Predict Development of New Cerebral Ischemic Events and Cerebral Hyperperfusion After Carotid Endarterectomy

Abstract

Risk factors for cerebrovascular complications developing during or after carotid endarterectomy (CEA) include preoperative impairments in cerebral hemodynamics, as detected by the demonstration of decreased cerebrovascular reactivity (CVR) to acetazolamide on brain perfusion SPECT. Central benzodiazepine receptor binding potential (CBRBP) and cerebral blood flow (CBF) images on SPECT provide high sensitivity and high specificity for detecting misery perfusion in patients with chronic unilateral major cerebral artery occlusive disease. The aim of the present study was to determine whether preoperative CBRBP/CBF images on SPECT could identify patients at risk for new cerebral ischemic events, including neurologic deficits and cerebral ischemic lesions on diffusionweighted MRI, or cerebral hyperperfusion after CEA and to compare the predictive accuracy of CBRBP/CBF with that of CVR to acetazolamide on SPECT. Methods: CBF, CVR, and CBRBP were assessed using N-isopropyl-p-123 I-iodoamphetamine ( 123 I-IMP) and 123 I-iomazenil SPECT before CEA in 112 patients with unilateral internal carotid artery stenosis ($70%). CBF measurement using 123 I-IMP SPECT was also performed immediately and 3 d after CEA. A region of interest was automatically placed in the middle cerebral artery territory in both cerebral hemispheres using a 3-dimensional stereotactic region-of-interest template. Diffusion-weighted MRI was performed within 3 d before and 24 h after surgery. Results: A preoperative increase in the affected side-to-contralateral side asymmetry on CBRBP/CBF value was the only significant independent predictor of postoperative new cerebral ischemic events (95% confidence intervals [CI], 1.145-1.608; P 5 0.0004) or post-CEA hyperperfusion (95% CI, 1.244-2.252; P 5 0.0007). There was no difference in the ability to predict post-CEA hyperperfusion when comparing the area under the receiver-operating-characteristic curve of the affected side-tocontralateral side asymmetry on CBRBP/CBF and that of the CVR in the affected hemisphere. However, the former value (0.924; 95% CI, 0.854-0.972) was significantly greater than the latter value (0.782; 95% CI, 0.697-0.852) for the prediction of new postoperative cerebral ischemic events (P , 0.05). Conclusion: Preoperative CBRBP/CBF images on SPECT can more accurately identify patients at risk for cerebrovascular complications occurring during or after CEA when compared with preoperative CVR to acetazolamide.

Measurement of changes in perfusion after carotid endarterectomy by 3D pseudo-continuous arterial spin labeling

“…When internal carotid plaque is removed, self-regulation of blood ow and dilation of blood vessels restore blood ow in the arterial lumen, recover intracranial blood supply and increase the cerebral perfusion pressure. Therefore, the e cacy of CEA should be evaluated on the basis of postoperative hemodynamics and cerebral perfusion recovery [16]. Our study con rmed that CEA signi cantly improved the severe preoperative reduction in intracranial perfusion.…”

Preoperative Cerebral Oxygen Extraction Fraction Imaging Generated from 7T MR Quantitative Susceptibility Mapping Predicts Development of Cerebral Hyperperfusion following Carotid Endarterectomy

“…This hypothesis is like the "normal perfusion pressure breakthrough" theory of Spetzler et al 13,15 Indeed, preoperative misery perfusion in the affected cerebral hemisphere is reportedly associated with the development of cerebral hyperperfusion following CEA or carotid stent placement for cervical ICA stenosis. 16,17 Misery perfusion is principally detected as an increased oxygen extraction fraction (OEF) on positron-emission tomography. 8 Several approaches have been attempted to measure OEF by using MR imaging techniques.…”

Intraoperative Perfusion Computed Tomography in Carotid Endarterectomy: Initial Experience in 16 Cases

“…PCT was performed at the selected level with the help of a bolus injection of contrast agent, and the PCT parameters obtained from time-density curve analysis were used to evaluate the brain perfusion. Compared to the other methods of perfusion imaging, such as positron emission tomography, single-photon emission computed tomography, xenon CT, and perfusion-weighted imaging [ 5 , 14 , 15 ], PCT was shown to have advantages of simplicity, short acquisition time, and providing a high-quality image. Therefore, PCT is widely used to diagnose acute cerebral ischemic stroke [ 16 ], to access delayed ischemia in patients with subarachnoid hemorrhage [ 17 ], to measure reserve capacity in patients with carotid occlusive disease using acetazolamide [ 18 ], to evaluate the effect of endovascular treatment and extracranial-intracranial bypass surgery [ 19 , 20 ], to predict hyperperfusion after surgery [ 21 ], and to diagnose and classify brain tumors [ 22 ].…”

“…The major complications of CEA include cerebral ischemia (due to hypoperfusion and dropped embolus) and cerebral hyperperfusion, both of which can result in intracranial hemorrhage and cognitive impairment. The intracranial hemorrhage and cognitive impairment are mainly caused by cerebral hemodynamic changes [ 5 – 7 ].…”