DETECTION OF EMBOLI AFTER SURGERY FOR INTRACEREBRAL ANEURYSMS

BACKGROUND: Neurological change after surgery for cerebral aneurysm ca used by embolic events is commonly suspected, but direct detection of emboli has not been possible in the past. Transcranial Doppler ultraso und (TCD) is able to detect emboli, and large numbers of emboli detect ed in TCD studies have been associated with radiological changes and c linical deterioration. METHODS: During a a-year period, 11 patients we re observed to have emboli during routine TCD studies after aneurysm s urgery. The computed tomographic (CT) scans of these patients were rev iewed for low-density areas, suggesting ischemia. All patients studied during al-year interval (July 1995-July 1996) served as a control gro up and were reviewed for similar CT findings, and the two groups were compared using Fisher's exact test. RESULTS: Nine of the 11 patients ( 82%) observed to have emboli developed low-density areas on their CT s cans, whereas 30 of the 123 (24%) patients without emboli developed lo w-density areas on their CT scans. The difference was significant (P < 0.001, Fisher's exact test). Credible sources for emboli were readily identified in each of the 11 patients. CONCLUSION: TCD allows detecti on of emboli after aneurysm surgery, and this detection is strongly as sociated with CT evidence of ischemia. Although detection of emboli wa s relatively rare in this study, rates of emboli occurrence may increa se if systematic monitoring is used.