Accuracy and prognostic consequences of ultrasonography in identifying severe XXXX . North American Symptomatic Carotid Endarterectomy Trial (NASCET) Group.

@entity1 @entity64 @entity2998 @entity850 @entity543
BACKGROUND AND PURPOSE: The accuracy of routine ultrasonography in detecting severe @entity543 was evaluated in comparison with cerebral angiography. The precision of ultrasonographic criteria in predicting the risk of @entity64 was also assessed. METHODS: A total of 1011 symptomatic carotid bifurcations were studied in @entity1 from the North American Symptomatic Carotid Endarterectomy Trial (NASCET). Given that all @entity1 were considered for entry into the trial, the chance of a verification bias affecting the analyses was minimized. The ultrasonographic data consisted of peak systolic velocities and frequency changes from both the internal and common carotid arteries. Angiographic @entity850 was calculated as in NASCET. Receiver operating characteristic (ROC) curves were constructed from the ultrasonographic data for the detection of 70% or greater @entity850 on the basis of an angiographic assessment. Kaplan-Meier @entity64 -free survival curves were used to predict the risk of @entity64 . RESULTS: The areas under the ROC curves ranged from 0.74 to 0.75 (95% confidence interval [CI], 0.69 to 0.79). The sensitivities and specificities ranged from 0.65 to 0.71. The risk of @entity64 at 18 months declined sharply as the degree of angiographically defined @entity850 declined from 99% to 70%. No pattern of decline was apparent on the basis of the ultrasonographic data. CONCLUSIONS: The results indicate that the accuracy of ultrasonography is moderate when flow parameters are used to assess the degree of @entity850 . Ultrasonography should be used as a screening tool to exclude @entity1 with no @entity2998 from further testing. Conventional angiography remains an essential investigation before assigning the risk of @entity64 and deciding appropriate treatment for extracranial @entity2998 .
