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Positron emission tomographic evaluation of patients with head and neck cancer undergoing occlusion and removal of the carotid artery.

We used positron emission tomography (PET) to evaluate cerebral metabolic changes in five patients who underwent resection of the internal carotid artery (ICA) for malignant tumors of the head and neck. These patients received a thorough clinical neurologic examination as well as neuroradiologic evaluation, including computed tomography (CT), magnetic resonance imaging (MRI), and PET of the head, before and after balloon occlusion of the ICA. All five were free of cerebral or peripheral vascular disease. In addition, each patient was evaluated with an electroencephalogram (EEG) before and during the balloon occlusion for signs of ischemic changes. No abnormalities were noted on clinical neurologic examination, CT, MRI, or EEG, either before or after occlusion, and excision of the ICA. The PET examination showed a mean preoperative metabolic rate of 7.52 mg of glucose/min/100 gm of brain tissue and a mean postoperative rate of 6.32 mg/min/100 gm of brain tissue; these values were within the normal range of 5.00 to 9.00 mg of glucose/min/100 gm of tissue observed at this center. Only one subject showed asymmetry of glucose metabolism; this subject had received radiation treatment to one side of the brain after the initial PET evaluation. The results of this study support our clinical experience with occlusion and resection of the ICA in patients with head and neck tumors that in the past have been considered inoperable.