Carotid Ultrasound Criteria for Detecting Intracranial Carotid Stenosis

<i>Background/Aims:</i> This study attempted to establish carotid ultrasound criteria for identifying stenosis of the intracranial internal carotid artery (ICA) and middle cerebral artery (MCA). <i>Methods:</i> Two hundred and fifty-five patients were enrolled. Ultrasound measurements for common carotid artery (CCA) and ICA were as follows: flow volume (FV), peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI) and resistance index (RI). The sensitivity and specificity of the ultrasound criteria for determining intracranial ICA or MCA ≧50% stenosis were calculated. <i>Results:</i> The criteria identified for detecting intracranial ICA ≧50% stenosis were ICA FV <159 ml/min, ICA PSV <33 cm/s and CCA PSV <42 cm/s. When ICA PSV <33 cm/s was combined with CCA PSV <42 cm/s, sensitivity increased to 82%, with 91% specificity. The criteria identified for detecting MCA ≧50% stenosis were CCA FV <285 ml/min, ICA FV <179 ml/min, ICA PSV <33 cm/s, >35% reduction in FV in the CCA, >40% reduction in FV in ICA, and >35% reduction in PSV in ICA. When these criteria were combined, sensitivity increased to 69%, with 85% specificity. <i>Conclusion:</i> This study demonstrated that ultrasound criteria are sensitive and specific for detecting intracranial ICA and MCA significant obstruction.