A 65-year-old man complains of having had slurred speech and no motor function or sensation of his right hand for 15 minutes. A left carotid bruit is heard in the neck. Which of the following diagnostic studies should be done?

C. Carotid arteriography.

D. Computed tomography (CT) of the brain.

DISCUSSION: Although a carotid duplex scan provides valuable information on the presence of significant carotid artery disease at its bifurcation, it cannot be used as the final test of the circulation to the brain in this particular case. Carotid duplex scanning has its greatest value in the assessment of asymptomatic patients who have cervical bruits. In that circumstance, it can provide information on which the decision for further workup can be based. When symptoms suggest a transient ischemic attack, no noninvasive study provides a complete evaluation and arteriography is mandatory. EEG is a valuable test for evaluating patients when seizure activity is suspected. In this patient, an EEG would be valuable only if all other diagnostic studies had been unrevealing. An arteriogram is mandatory in this patient to adequately evaluate the entire extracranial and intracranial cerebral circulation. If a duplex scan had been performed and had revealed no disease, an arteriogram would still be necessary to exclude brachiocephalic trunk disease as a source of emboli. Likewise, intracranial narrowing would also be missed by such a noninvasive study. For these reasons, duplex scanning might be considered redundant and inadequate in these circumstances. CT of the head would be imperative in the evaluation of this patient. Its primary role is to exclude cerebral infarction, even in the presence of transient symptoms. It also distinguishes an ischemic cerebral event from an intracranial hemorrhage and rules out other potential causes of the symptoms, such as a brain tumor, other space-occupying intracranial lesions, and arteriovenous malformation.