RESUMO
Both carotid bifurcations were examined in 353 patients over a 20-month interval using a combination of real-time and pulsed Doppler ultrasound (duplex scanning). Angiographic correlation was available in 72 cases. Stenosis of the internal carotid was evaluated using a Doppler input frequency of 5 MHz and a scan angle of 60 degrees. A peak frequency shift of less than 3.5 kHz was found to be a sign of less than or equal to 30% stenosis; 3.5-4 kHz with moderate turbulence suggested 31-50% stenosis, 4-8 kHz 51-90% stenosis, and greater than 8 kHz greater than 90% stenosis. Subtotal stenosis (greater than 95%) was manifested by a frequency shift of less than 8 kHz, but the waveform was totally distorted. Overall accuracy improved from 77% for the first 6 months to 87% for the last 14 months. For stenosis greater than 50%, sensitivity improved from 82% to 97% during this period. Analysis of errors and suggestions for avoiding them are presented.
Assuntos
Doenças das Artérias Carótidas/diagnóstico , Ultrassonografia/métodos , Artérias Carótidas/diagnóstico por imagem , Artérias Carótidas/patologia , Doenças das Artérias Carótidas/diagnóstico por imagem , Artéria Carótida Interna/diagnóstico por imagem , Artéria Carótida Interna/patologia , Constrição Patológica/diagnóstico , Constrição Patológica/diagnóstico por imagem , Erros de Diagnóstico , Estudos de Avaliação como Assunto , Humanos , RadiografiaRESUMO
This article reviews the uses of arteriography, venous digital subtraction angiography, and duplex carotid sonography in the evaluation of patients with an asymptomatic carotid bruit or carotid system transient ischemic attack. It concludes with a description of the authors' guidelines for their use.