Detection and monitoring of vasospasm and delayed cerebral ischemia: a review and assessment of the literature.

Delayed cerebral ischemia (DCI) after subarachnoid hemorrhage can be evaluated using clinical assessment, non-invasive and invasive techniques. An electronic literature search was conducted on English-language articles investigating DCI in human subjects with subarachnoid hemorrhage. A total of 31 relevant papers were identified evaluating the role of clinical assessment, transcranial Doppler, computed tomographic angiography, and computed tomographic perfusion. Clinical assessment by bedside evaluations is limited, especially in patients initially in poorer clinical condition or who are receiving sedative medication for whom deterioration may be more difficult to identify. Transcranial Doppler is a useful screening tool for middle cerebral artery vasospasm, with less utility in evaluating other intracranial vessels. Computed tomographic angiography correlates well with digital subtraction angiography. Computed tomographic perfusion may help predict DCI when used early or identify DCI when used later.