BACKGROUND AND PURPOSE: Although asymptomatic embolization can be detected in @entity1 with @entity543 , its temporal variability is unclear. An understanding of this is important in designing optimal recording protocols for future prospective studies of the predictive value of @entity887 ( @entity887 ). We determined the effect of repeating and extending recording times in @entity1 with symptomatic and asymptomatic @entity543 . METHODS: In 20 asymptomatic and 20 symptomatic subjects with > 60% @entity543 , we used transcranial Doppler ultrasound to record for @entity887 in the ipsilateral middle cerebral artery. Three 1-hour recordings were performed on three separate days, and on one occasion (not necessarily the first) the recording was extended to 2 hours. The recordings were saved onto digital tape for subsequent blinded analysis. RESULTS: Marked temporal variability was seen in symptomatic @entity1 in whom the cumulative proportion of subjects with @entity887 increased from 10 (50%) after a single hour of recording to 12 (60%) and 15 (75%) after two and three recordings, respectively. Extending the recording to 2 hours increased the yield of @entity887 -positive @entity1 from 6 (30%) to 8 (40%). In symptomatic @entity1 there was excellent agreement between whether @entity1 were positive for @entity887 during each of two consecutive 1-hour recordings (kappa = 0.78, P = 0.0003) but poor agreement between the results of two single-hour recordings performed on different days (kappa = 0.22, P = 0.27). In asymptomatic @entity1 , 4 (20%) were @entity887 positive during the first hour; this increased to 5 (25%) after the recording was repeated once, with no further increase after the third recording. Extending the recording to 2 hours increased the yield from 3 (15%) to 7 (35%). In contrast to symptomatic stenoses, in @entity1 with asymptomatic stenoses there was fair agreement between whether @entity1 were @entity887 positive on two consecutive 1-hour recordings (kappa = 0.49, P = 0.01) or two single-hour recordings performed on different days (kappa = 0.48, P = 0.02). Symptomatic subjects were more likely to have @entity887 (when @entity20288 -hour recordings were considered, 24/60 versus 10/60; P = 0.0046). @entity887 in symptomatic subjects had a higher relative intensity increase than in asymptomatic subjects (P = 0.01). CONCLUSIONS: The temporal variability of @entity887 needs to be taken into account in the design of optimal recording protocols and comparisons of results from different studies. Extending the duration of recording beyond an hour in symptomatic stenoses is of less value, but repeating the recording on a different day will often identify additional subjects with @entity887 . In intervention studies in symptomatic @entity1 , the time since last symptoms must be considered. In asymptomatic @entity850 , extending the duration of recording beyond an hour will increase the proportion of @entity1 positive for @entity887 .

Temporal variability of asymptomatic embolization in XXXX and optimal recording protocols.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity20288 :: ('100310785', 'Gene') :: ['all 1'] @entity887 :: ('MESH:D004617', 'Disease') :: ['ES', 'embolic signals'] @entity850 :: ('MESH:D003251', 'Disease') :: ['stenosis'] @entity543 :: ('MESH:D016893', 'Disease') :: ['carotid stenosis', 'carotid artery stenosis']
@entity543 :: (MESH:D016893,Disease) :: ['carotid artery stenosis']
